Publications

Selected Publications

High-resolution CMOS MEA platform to study neurons at subcellular, cellular, and network levels

Presenting measurements of neuronal preparations with a novel CMOS-based microelectrode array at high-spatiotemporal-resolution on subcellular, cellular, and network level.

J. Müller, M. Ballini, P. Livi, Y. Chen, M. Radivojevic, A. Shadmani, V. Viswam, I. L. Jones, M. Fiscella, R. Diggelmann, A. Stettler, U. Frey, D. J. Bakkum, and A. Hierlemann, “High-resolution CMOS MEA platform to study neurons at subcellular, cellular, and network levels,” Lab Chip, vol. 15, no. 13, pp. 2767–2780, May 2015.

Revealing Neuronal Function through Microelectrode Array Recordings

Reviewing the current understanding of microelectrode signals and the techniques for analyzing them, with focus on the ongoing advancements in microelectrode technology (in vivo and in vitro) and recent advanced microelectrode array measurement methods that facilitate the understanding of single neurons and network function.

M. E. J. Obien, K. Deligkaris, T. Bullmann, D. J. Bakkum, and U. Frey, “Revealing Neuronal Function through Microelectrode Array Recordings,” Front. Neurosci., 8:423, Jan 2015.

A 1024-Channel CMOS Microelectrode Array With 26,400 Electrodes for Recording and Stimulation of Electrogenic Cells In Vitro

A high-resolution CMOS-based microelectrode array featuring 1,024 low-noise readout channels, 26,400 electrodes at a density of 3,265 electrodes per mm², including on-chip 10bit ADCs and consuming only 75 mW.

M. Ballini, J. Muller, P. Livi, Y. Chen, U. Frey, A. Stettler, A. Shadmani, V. Viswam, I. L. Jones, D. Jackel, M. Radivojevic, M. K. Lewandowska, W. Gong, M. Fiscella, D. J. Bakkum, F. Heer, and A. Hierlemann, “A 1024-Channel CMOS Microelectrode Array With 26,400 Electrodes for Recording and Stimulation of Electrogenic Cells In Vitro,” IEEE Journal of Solid-State Circuits, vol. 49, no. 11, pp. 2705-2719, 2014.

Tracking axonal action potential propagation on a high-density microelectrode array across hundreds of sites

Demonstrating a method to electrically visualize action potential propagation on axons and revealing
large variations in velocity.

D. J. Bakkum, U. Frey, M. Radivojevic, T. L. Russell, J. Muller, M. Fiscella, H. Takahashi, and A. Hierlemann, “Tracking axonal action potential propagation on a high-density microelectrode array across hundreds of sites,” Nature Communications, 4:2181, Jul 2013.

Microelectronic System for High-Resolution Mapping of Extracellular Electric Fields Applied to Brain Slices

Recording and modeling extracellular action potentials of Purkinje cells at subcellular resolution.

U. Frey, U. Egert, F. Heer, S. Hafizovic, and A. Hierlemann, “Microelectronic System for High-Resolution Mapping of Extracellular Electric Fields Applied to Brain Slices,” Biosensors and Bioelectronics, vol. 24, no. 7, pp. 2191-2198, 2009.

Modulation of Cardiomyocyte Electrical Properties Using Regulated Bone Morphogenetic Protein-2 Expression

Controlling BMP-2 expression to modulate the electrophysiological properties of cardiomyocytes using an HD-MEA for detailed monitoring.

C. D. Sanchez-Bustamante, U. Frey, J. M. Kelm, A. Hierlemann, and M. Fussenegger,
“Modulation of Cardiomyocyte Electrical Properties Using Regulated Bone Morphogenetic Protein-2 Expression,” Tissue Engineering Part A, vol. 14, no. 12, pp. 1969-1988, 2008.

All Publications

235 entries « ‹ 4 of 12 › »

61.	Duru, Jens; Rüfenacht, Arielle; Löhle, Josephine; Pozzi, Marcello; Forró, Csaba; Ledermann, Linus; Bernardi, Aeneas; Matter, Michael; Renia, André; Simona, Benjamin; Tringides, Christina M; Bernhard, Stéphane; Ihle, Stephan J; Hengsteler, Julian; Maurer, Benedikt; Zhanga, Xinyu; Nakatsuka, Nako: Driving electrochemical reactions at the microscale using CMOS microelectrode arrays. In: Lab on a Chip, 2023, ISSN: 1473-0189. (Type: Journal Article \| Abstract \| Links \| BibTeX) @article{Duru2023c, title = {Driving electrochemical reactions at the microscale using CMOS microelectrode arrays}, author = {Jens Duru and Arielle Rüfenacht and Josephine Löhle and Marcello Pozzi and Csaba Forró and Linus Ledermann and Aeneas Bernardi and Michael Matter and André Renia and Benjamin Simona and Christina M. Tringides and Stéphane Bernhard and Stephan J. Ihle and Julian Hengsteler and Benedikt Maurer and Xinyu Zhanga and Nako Nakatsuka}, url = {https://pubs.rsc.org/en/content/articlelanding/2023/lc/d3lc00630a}, doi = {10.1039/D3LC00630A}, issn = {1473-0189}, year = {2023}, date = {2023-10-30}, journal = {Lab on a Chip}, abstract = {Precise control of pH values at electrode interfaces enables the systematic investigation of pH-dependent processes by electrochemical means. In this work, we employed high-density complementary metal-oxide-semiconductor (CMOS) microelectrode arrays (MEAs) as miniaturized systems to induce and confine electrochemical reactions in areas corresponding to the pitch of single electrodes (17.5 μm). First, we present a strategy for generating localized pH patterns on the surface of the CMOS MEA with unprecedented spatial resolution. Leveraging the versatile routing capabilities of the switch matrix beneath the CMOS MEA, we created arbitrary combinations of anodic and cathodic electrodes and hence pH patterns. Moreover, we utilized the system to produce polymeric surface patterns by additive and subtractive methods. For additive patterning, we controlled the in situ formation of polydopamine at the microelectrode surface through oxidation of free dopamine above a threshold pH > 8.5. For subtractive patterning, we removed cell-adhesive poly-L-lysine from the electrode surface and backfilled the voids with antifouling polymers. Such polymers were chosen to provide a proof-of-concept application of controlling neuronal growth via electrochemically-induced patterns on the CMOS MEA surface. Importantly, our platform is compatible with commercially available high-density MEAs and requires no custom equipment, rendering the findings generalizable and accessible.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Close Precise control of pH values at electrode interfaces enables the systematic investigation of pH-dependent processes by electrochemical means. In this work, we employed high-density complementary metal-oxide-semiconductor (CMOS) microelectrode arrays (MEAs) as miniaturized systems to induce and confine electrochemical reactions in areas corresponding to the pitch of single electrodes (17.5 μm). First, we present a strategy for generating localized pH patterns on the surface of the CMOS MEA with unprecedented spatial resolution. Leveraging the versatile routing capabilities of the switch matrix beneath the CMOS MEA, we created arbitrary combinations of anodic and cathodic electrodes and hence pH patterns. Moreover, we utilized the system to produce polymeric surface patterns by additive and subtractive methods. For additive patterning, we controlled the in situ formation of polydopamine at the microelectrode surface through oxidation of free dopamine above a threshold pH > 8.5. For subtractive patterning, we removed cell-adhesive poly-L-lysine from the electrode surface and backfilled the voids with antifouling polymers. Such polymers were chosen to provide a proof-of-concept application of controlling neuronal growth via electrochemically-induced patterns on the CMOS MEA surface. Importantly, our platform is compatible with commercially available high-density MEAs and requires no custom equipment, rendering the findings generalizable and accessible. Close https://pubs.rsc.org/en/content/articlelanding/2023/lc/d3lc00630a doi:10.1039/D3LC00630A Close
62.	hiya Lv,; He, Enhui; Luo, Jinping; Liu, Yaoyao; Liang, Wei; Xu, Shihong; Zhang, Kui; Yang, Yan; Wang, Mixia; Song, Yilin; Wu, Yirong; Cai, Xinxia: Using Human-Induced Pluripotent Stem Cell Derived Neurons on Microelectrode Arrays to Model Neurological Disease: A Review. In: Advanced Science, 2023. (Type: Journal Article \| Abstract \| Links \| BibTeX) @article{Lv2023, title = {Using Human-Induced Pluripotent Stem Cell Derived Neurons on Microelectrode Arrays to Model Neurological Disease: A Review}, author = {hiya Lv and Enhui He and Jinping Luo and Yaoyao Liu and Wei Liang and Shihong Xu and Kui Zhang and Yan Yang and Mixia Wang and Yilin Song and Yirong Wu and Xinxia Cai}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/advs.202301828}, doi = {10.1002/advs.202301828}, year = {2023}, date = {2023-10-23}, journal = {Advanced Science}, abstract = {In situ physiological signals of in vitro neural disease models are essential for studying pathogenesis and drug screening. Currently, an increasing number of in vitro neural disease models are established using human-induced pluripotent stem cell (hiPSC) derived neurons (hiPSC-DNs) to overcome interspecific gene expression differences. Microelectrode arrays (MEAs) can be readily interfaced with two-dimensional (2D), and more recently, three-dimensional (3D) neural stem cell-derived in vitro models of the human brain to monitor their physiological activity in real time. Therefore, MEAs are emerging and useful tools to model neurological disorders and disease in vitro using human iPSCs. This is enabling a real-time window into neuronal signaling at the network scale from patient derived. This paper provides a comprehensive review of MEA’s role in analyzing neural disease models established by hiPSC-DNs. It covers the significance of MEA fabrication, surface structure and modification schemes for hiPSC-DNs culturing and signal detection. Additionally, this review discusses advances in the development and use of MEA technology to study in vitro neural disease models, including epilepsy, autism spectrum developmental disorder (ASD), and others established using hiPSC-DNs. The paper also highlights the application of MEAs combined with hiPSC-DNs in detecting in vitro neurotoxic substances. Finally, the future development and outlook of multifunctional and integrated devices for in vitro medical diagnostics and treatment are discussed.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Close In situ physiological signals of in vitro neural disease models are essential for studying pathogenesis and drug screening. Currently, an increasing number of in vitro neural disease models are established using human-induced pluripotent stem cell (hiPSC) derived neurons (hiPSC-DNs) to overcome interspecific gene expression differences. Microelectrode arrays (MEAs) can be readily interfaced with two-dimensional (2D), and more recently, three-dimensional (3D) neural stem cell-derived in vitro models of the human brain to monitor their physiological activity in real time. Therefore, MEAs are emerging and useful tools to model neurological disorders and disease in vitro using human iPSCs. This is enabling a real-time window into neuronal signaling at the network scale from patient derived. This paper provides a comprehensive review of MEA’s role in analyzing neural disease models established by hiPSC-DNs. It covers the significance of MEA fabrication, surface structure and modification schemes for hiPSC-DNs culturing and signal detection. Additionally, this review discusses advances in the development and use of MEA technology to study in vitro neural disease models, including epilepsy, autism spectrum developmental disorder (ASD), and others established using hiPSC-DNs. The paper also highlights the application of MEAs combined with hiPSC-DNs in detecting in vitro neurotoxic substances. Finally, the future development and outlook of multifunctional and integrated devices for in vitro medical diagnostics and treatment are discussed. Close https://onlinelibrary.wiley.com/doi/abs/10.1002/advs.202301828 doi:10.1002/advs.202301828 Close
63.	Kelley, Matt R; Chipman, Laura B; Asano, Shoh; Knott, Matthew; Howard, Samantha T; Berg, Allison P: Potentiating NaV1.1 in Dravet syndrome patient iPSC-derived GABAergic neurons increases neuronal firing frequency and decreases network synchrony. In: bioRxiv, 2023. (Type: Journal Article \| Abstract \| Links \| BibTeX) @article{Kelley2023, title = {Potentiating NaV1.1 in Dravet syndrome patient iPSC-derived GABAergic neurons increases neuronal firing frequency and decreases network synchrony}, author = {Matt R Kelley and Laura B Chipman and Shoh Asano and Matthew Knott and Samantha T Howard and Allison P Berg}, url = {https://www.biorxiv.org/content/10.1101/2023.09.28.559990v1}, doi = {10.1101/2023.09.28.559990}, year = {2023}, date = {2023-09-29}, journal = {bioRxiv}, abstract = {Dravet syndrome is a developmental and epileptic encephalopathy characterized by seizures, behavioral abnormalities, developmental deficits, and elevated risk of sudden unexpected death in epilepsy (SUDEP). Most patient cases are caused by de novo loss-of-function mutations in the gene SCN1A, causing a haploinsufficiency of the alpha subunit of the voltage-gated sodium channel NaV1.1. Within the brain, NaV1.1 is primarily localized to the axons of inhibitory neurons, and decreased NaV1.1 function is hypothesized to reduce GABAergic inhibitory neurotransmission within the brain, driving neuronal network hyperexcitability and subsequent pathology. We have developed a human in vitro model of Dravet syndrome using differentiated neurons derived from patient iPSC and enriched for GABA expressing neurons. Neurons were plated on high definition multielectrode arrays (HD-MEAs), permitting recordings from the same cultures over the 7-weeks duration of study at the network, single cell, and subcellular resolution. Using this capability, we characterized the features of axonal morphology and physiology. Neurons developed increased spiking activity and synchronous network bursting. Recordings were processed through a spike sorting pipeline for curation of single unit activity and to assess the effects of pharmacological treatments. At 7-weeks, the application of the GABAAR receptor agonist muscimol eliminated network bursting, indicating the presence of GABAergic neurotransmission. To identify the role of NaV1.1 on neuronal and network activity, cultures were treated with a dose-response of the NaV1.1 potentiator δ-theraphotoxin-Hm1a. This resulted in a strong increase in firing rates of putative GABAergic neurons, an increase in the intraburst firing rate, and eliminated network bursting. These results validate that potentiation of NaV1.1 in Dravet patient iPSC-derived neurons results in decreased firing synchrony in neuronal networks through increased GABAergic neuron activity and support the use of human neurons and HD-MEAs as viable high-throughput electrophysiological platform to enable therapeutic discovery.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Close Dravet syndrome is a developmental and epileptic encephalopathy characterized by seizures, behavioral abnormalities, developmental deficits, and elevated risk of sudden unexpected death in epilepsy (SUDEP). Most patient cases are caused by de novo loss-of-function mutations in the gene SCN1A, causing a haploinsufficiency of the alpha subunit of the voltage-gated sodium channel NaV1.1. Within the brain, NaV1.1 is primarily localized to the axons of inhibitory neurons, and decreased NaV1.1 function is hypothesized to reduce GABAergic inhibitory neurotransmission within the brain, driving neuronal network hyperexcitability and subsequent pathology. We have developed a human in vitro model of Dravet syndrome using differentiated neurons derived from patient iPSC and enriched for GABA expressing neurons. Neurons were plated on high definition multielectrode arrays (HD-MEAs), permitting recordings from the same cultures over the 7-weeks duration of study at the network, single cell, and subcellular resolution. Using this capability, we characterized the features of axonal morphology and physiology. Neurons developed increased spiking activity and synchronous network bursting. Recordings were processed through a spike sorting pipeline for curation of single unit activity and to assess the effects of pharmacological treatments. At 7-weeks, the application of the GABAAR receptor agonist muscimol eliminated network bursting, indicating the presence of GABAergic neurotransmission. To identify the role of NaV1.1 on neuronal and network activity, cultures were treated with a dose-response of the NaV1.1 potentiator δ-theraphotoxin-Hm1a. This resulted in a strong increase in firing rates of putative GABAergic neurons, an increase in the intraburst firing rate, and eliminated network bursting. These results validate that potentiation of NaV1.1 in Dravet patient iPSC-derived neurons results in decreased firing synchrony in neuronal networks through increased GABAergic neuron activity and support the use of human neurons and HD-MEAs as viable high-throughput electrophysiological platform to enable therapeutic discovery. Close https://www.biorxiv.org/content/10.1101/2023.09.28.559990v1 doi:10.1101/2023.09.28.559990 Close
64.	Metto, Abigael C; Telgkamp, Petra; McLane-Svoboda, Autumn K; Gilad, Assaf A; Pelled, Galit: Closed-loop neurostimulation via expression of magnetogenetics-sensitive protein in inhibitory neurons leads to reduction of seizure activity in a rat model of epilepsy. In: Brain Research, 2023. (Type: Journal Article \| Abstract \| Links \| BibTeX) @article{Metto2023, title = {Closed-loop neurostimulation via expression of magnetogenetics-sensitive protein in inhibitory neurons leads to reduction of seizure activity in a rat model of epilepsy}, author = {Abigael C. Metto and Petra Telgkamp and Autumn K. McLane-Svoboda and Assaf A. Gilad and Galit Pelled}, url = {https://www.sciencedirect.com/science/article/pii/S0006899323003621}, doi = {https://doi.org/10.1016/j.brainres.2023.148591}, year = {2023}, date = {2023-09-24}, journal = {Brain Research}, abstract = {On-demand neurostimulation has shown success in epilepsy patients with pharmacoresistant seizures. Seizures produce magnetic fields that can be recorded using magnetoencephalography. We developed a new closed-loop approach to control seizure activity based on magnetogenetics using the electromagnetic perceptive gene (EPG) that encodes a protein that responds to magnetic fields. The EPG transgene was expressed in inhibitory interneurons under the hDlx promoter and kainic acid was used to induce acute seizures. In vivo electrophysiological signals were recorded. We found that hDlx EPG rats exhibited a significant delay in the onset of first seizure (1142.72 ± 186.35 s) compared to controls (644.03 ± 15.06 s) and significantly less seizures (4.11 ± 1.03) compared to controls (8.33 ± 1.58). These preliminary findings suggest that on-demand activation of EPG expressed in inhibitory interneurons suppresses seizure activity, and magnetogenetics via EPG may be an effective strategy to alleviate seizure severity in a closed-loop, and cell-specific fashion.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Close On-demand neurostimulation has shown success in epilepsy patients with pharmacoresistant seizures. Seizures produce magnetic fields that can be recorded using magnetoencephalography. We developed a new closed-loop approach to control seizure activity based on magnetogenetics using the electromagnetic perceptive gene (EPG) that encodes a protein that responds to magnetic fields. The EPG transgene was expressed in inhibitory interneurons under the hDlx promoter and kainic acid was used to induce acute seizures. In vivo electrophysiological signals were recorded. We found that hDlx EPG rats exhibited a significant delay in the onset of first seizure (1142.72 ± 186.35 s) compared to controls (644.03 ± 15.06 s) and significantly less seizures (4.11 ± 1.03) compared to controls (8.33 ± 1.58). These preliminary findings suggest that on-demand activation of EPG expressed in inhibitory interneurons suppresses seizure activity, and magnetogenetics via EPG may be an effective strategy to alleviate seizure severity in a closed-loop, and cell-specific fashion. Close https://www.sciencedirect.com/science/article/pii/S0006899323003621 doi:https://doi.org/10.1016/j.brainres.2023.148591 Close
65.	Levi, Timothee; Beaubois, Romain; Cheslet, Jérémy; Duenki, Tomoya; Khoyratee, Farad; Branchereau, Pascal; Ikeuchi, Yoshiho: BiœmuS: A new tool for neurological disorders studies through real-time emulation and hybridization using biomimetic Spiking Neural Network. In: Research Square, 2023. (Type: Journal Article \| Abstract \| Links \| BibTeX) @article{Levi2023, title = {BiœmuS: A new tool for neurological disorders studies through real-time emulation and hybridization using biomimetic Spiking Neural Network}, author = {Timothee Levi and Romain Beaubois and Jérémy Cheslet and Tomoya Duenki and Farad Khoyratee and Pascal Branchereau and Yoshiho Ikeuchi}, url = {https://www.researchsquare.com}, doi = {10.21203/rs.3.rs-3191285/v1}, year = {2023}, date = {2023-09-15}, journal = {Research Square}, abstract = {Characterization and modeling of biological neural networks is a field opening to major advances in our understanding of the mechanisms governing the functioning of the brain and the different pathologies that can affect it. Recent researches in bioelectronics and neuromorphic engineering lead to the design of the new generation of neuroprosthesis. Here we show a novel real-time, biomimetic and energy-efficient neural network for bio-hybrid experiments and parallel emulation. This novel system is used to investigate and reproduce neural network dynamics. The setup is running on a digital platform using a System on Chip (SoC) featuring both Programmable Logic (PL) and processors in a Processing System (PS) part. The FPGA part is computing the biomimetic and real-time electrical activities of Hodgkin-Huxley neural network while the processors handle monitoring and communication. New methods of resource and power optimization has been applied to the FPGA to allow detailed neuron modeling with synapses showing short term plasticity. The system is validated by comparison with biological data and model. We also demonstrate the feasibility of bio-hybrid experiments with different bio-physical interface and different biological cells. The complete setup achieves communication with a fully flexible real-time device thus constituting a step towards neuromorphic-based neuroprosthesis for bioelectrical therapeutics.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Close Characterization and modeling of biological neural networks is a field opening to major advances in our understanding of the mechanisms governing the functioning of the brain and the different pathologies that can affect it. Recent researches in bioelectronics and neuromorphic engineering lead to the design of the new generation of neuroprosthesis. Here we show a novel real-time, biomimetic and energy-efficient neural network for bio-hybrid experiments and parallel emulation. This novel system is used to investigate and reproduce neural network dynamics. The setup is running on a digital platform using a System on Chip (SoC) featuring both Programmable Logic (PL) and processors in a Processing System (PS) part. The FPGA part is computing the biomimetic and real-time electrical activities of Hodgkin-Huxley neural network while the processors handle monitoring and communication. New methods of resource and power optimization has been applied to the FPGA to allow detailed neuron modeling with synapses showing short term plasticity. The system is validated by comparison with biological data and model. We also demonstrate the feasibility of bio-hybrid experiments with different bio-physical interface and different biological cells. The complete setup achieves communication with a fully flexible real-time device thus constituting a step towards neuromorphic-based neuroprosthesis for bioelectrical therapeutics. Close https://www.researchsquare.com doi:10.21203/rs.3.rs-3191285/v1 Close
66.	Silverman, Jill L; Fenton, Timothy; Haouchine, Olivia; Hallam, Elizabeth; Smith, Emily; Jackson, Kiya; Rahbarian, Darlene; Canales, Cesar; Adhikari, Anna; Nord, Alex; Ben-Shalom, Roy: Hyperexcitability and translational phenotypes in a preclinical model of SYNGAP1mutations. In: Research Square, 2023. (Type: Journal Article \| Abstract \| Links \| BibTeX) @article{Silverman2023, title = {Hyperexcitability and translational phenotypes in a preclinical model of SYNGAP1mutations}, author = {Jill L. Silverman and Timothy Fenton and Olivia Haouchine and Elizabeth Hallam and Emily Smith and Kiya Jackson and Darlene Rahbarian and Cesar Canales and Anna Adhikari and Alex Nord and Roy Ben-Shalom}, url = {https://www.researchsquare.com/article/rs-3246655/v1}, doi = {https://doi.org/10.21203/rs.3.rs-3246655/v1}, year = {2023}, date = {2023-09-13}, journal = {Research Square}, abstract = {SYNGAP1is a critical gene for neuronal development, synaptic structure, and function. Although rare, the disruption of SYNGAP1directly causes a genetically identi able neurodevelopmental disorder (NDD) called SYNGAP1-related intellectual disability. Without functional SynGAP1 protein, patients present with intellectual disability, motor impairments, and epilepsy. Previous work using mouse models with a variety of germline and conditional mutations has helped delineate SynGAP1’s critical roles in neuronal structure and function, as well as key biochemical signaling pathways essential to synapse integrity. Homozygous loss of SYNGAP1is embryonically lethal. Heterozygous mutations of SynGAP1result in a broad range of phenotypes including increased locomotor activity, impaired working spatial memory, impaired cued fear memory, and increased stereotypic behavior. Ourinvivofunctional data, using the original germline mutation mouse line from the Huganir laboratory, corroborated robust hyperactivity and learning and memory de cits. Here, we describe impairments in the translational biomarker domain of sleep, characterized using neurophysiological data collected with wireless telemetric electroencephalography (EEG). We discoveredSyngap1+/− mice exhibited elevated spike trains in both number and duration, in addition to elevated power, most notably in the delta power band. Primary neurons fromSyngap1+/− mice displayed increased network ring activity, greater spikes per burst, and shorter inter-burst intervals between peaks using high density micro-electrode arrays (HD-MEA). This work is translational, innovative, and highly signi cant as it outlines functional impairments in Syngap1mutant mice. Simultaneously, the work utilized untethered, wireless neurophysiology that can discover potential biomarkers of Syngap1RID, for clinical trials, as it has done with other NDDs. Our work is substantial forward progress toward translational work for SynGAP1R-ID as it bridges in-vitroelectrophysiological neuronal activity and function with invivoneurophysiological brain activity and function. These data elucidate multiple quantitative, translational biomarkers invivoand invitrofor the development of treatments for SYNGAP1-related intellectual disability.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Close SYNGAP1is a critical gene for neuronal development, synaptic structure, and function. Although rare, the disruption of SYNGAP1directly causes a genetically identi able neurodevelopmental disorder (NDD) called SYNGAP1-related intellectual disability. Without functional SynGAP1 protein, patients present with intellectual disability, motor impairments, and epilepsy. Previous work using mouse models with a variety of germline and conditional mutations has helped delineate SynGAP1’s critical roles in neuronal structure and function, as well as key biochemical signaling pathways essential to synapse integrity. Homozygous loss of SYNGAP1is embryonically lethal. Heterozygous mutations of SynGAP1result in a broad range of phenotypes including increased locomotor activity, impaired working spatial memory, impaired cued fear memory, and increased stereotypic behavior. Ourinvivofunctional data, using the original germline mutation mouse line from the Huganir laboratory, corroborated robust hyperactivity and learning and memory de cits. Here, we describe impairments in the translational biomarker domain of sleep, characterized using neurophysiological data collected with wireless telemetric electroencephalography (EEG). We discoveredSyngap1+/− mice exhibited elevated spike trains in both number and duration, in addition to elevated power, most notably in the delta power band. Primary neurons fromSyngap1+/− mice displayed increased network ring activity, greater spikes per burst, and shorter inter-burst intervals between peaks using high density micro-electrode arrays (HD-MEA). This work is translational, innovative, and highly signi cant as it outlines functional impairments in Syngap1mutant mice. Simultaneously, the work utilized untethered, wireless neurophysiology that can discover potential biomarkers of Syngap1RID, for clinical trials, as it has done with other NDDs. Our work is substantial forward progress toward translational work for SynGAP1R-ID as it bridges in-vitroelectrophysiological neuronal activity and function with invivoneurophysiological brain activity and function. These data elucidate multiple quantitative, translational biomarkers invivoand invitrofor the development of treatments for SYNGAP1-related intellectual disability. Close https://www.researchsquare.com/article/rs-3246655/v1 doi:https://doi.org/10.21203/rs.3.rs-3246655/v1 Close
67.	Habibollahi, Forough; Kagan, Brett J; Burkitt, Anthony N; French, Chris: Critical dynamics arise during structured information presentation within embodied in vitro neuronal networks. In: Nature Communications, 2023. (Type: Journal Article \| Abstract \| Links \| BibTeX) @article{Habibollahi2023, title = {Critical dynamics arise during structured information presentation within embodied in vitro neuronal networks}, author = {Forough Habibollahi and Brett J. Kagan and Anthony N. Burkitt and Chris French }, url = {https://www.nature.com/articles/s41467-023-41020-3}, doi = {https://doi.org/10.1038/s41467-023-41020-3}, year = {2023}, date = {2023-08-30}, journal = {Nature Communications}, abstract = {Understanding how brains process information is an incredibly difficult task. Amongst the metrics characterising information processing in the brain, observations of dynamic near-critical states have generated significant interest. However, theoretical and experimental limitations associated with human and animal models have precluded a definite answer about when and why neural criticality arises with links from attention, to cognition, and even to consciousness. To explore this topic, we used an in vitro neural network of cortical neurons that was trained to play a simplified game of ‘Pong’ to demonstrate Synthetic Biological Intelligence (SBI). We demonstrate that critical dynamics emerge when neural networks receive task-related structured sensory input, reorganizing the system to a near-critical state. Additionally, better task performance correlated with proximity to critical dynamics. However, criticality alone is insufficient for a neuronal network to demonstrate learning in the absence of additional information regarding the consequences of previous actions. These findings offer compelling support that neural criticality arises as a base feature of incoming structured information processing without the need for higher order cognition.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Close Understanding how brains process information is an incredibly difficult task. Amongst the metrics characterising information processing in the brain, observations of dynamic near-critical states have generated significant interest. However, theoretical and experimental limitations associated with human and animal models have precluded a definite answer about when and why neural criticality arises with links from attention, to cognition, and even to consciousness. To explore this topic, we used an in vitro neural network of cortical neurons that was trained to play a simplified game of ‘Pong’ to demonstrate Synthetic Biological Intelligence (SBI). We demonstrate that critical dynamics emerge when neural networks receive task-related structured sensory input, reorganizing the system to a near-critical state. Additionally, better task performance correlated with proximity to critical dynamics. However, criticality alone is insufficient for a neuronal network to demonstrate learning in the absence of additional information regarding the consequences of previous actions. These findings offer compelling support that neural criticality arises as a base feature of incoming structured information processing without the need for higher order cognition. Close https://www.nature.com/articles/s41467-023-41020-3 doi:https://doi.org/10.1038/s41467-023-41020-3 Close
68.	Radivojevic, Milos; Punga, Anna Rostedt: Functional imaging of conduction dynamics in cortical and spinal axons. In: eLife, 2023. (Type: Journal Article \| Abstract \| Links \| BibTeX) @article{Radivojevic2023_2, title = {Functional imaging of conduction dynamics in cortical and spinal axons}, author = {Milos Radivojevic and Anna Rostedt Punga}, url = {https://elifesciences.org/articles/86512}, doi = {https://doi.org/10.7554/eLife.86512}, year = {2023}, date = {2023-08-22}, journal = {eLife}, abstract = {Mammalian axons are specialized for transmitting action potentials to targets within the central and peripheral nervous system. A growing body of evidence suggests that, besides signal conduction, axons play essential roles in neural information processing, and their malfunctions are common hallmarks of neurodegenerative diseases. The technologies available to study axonal function and structure integrally limit the comprehension of axon neurobiology. High-density microelectrode arrays (HD-MEAs) allow for accessing axonal action potentials at high spatiotemporal resolution, but provide no insights on axonal morphology. Here, we demonstrate a method for electrical visualization of axonal morphologies based on extracellular action potentials recorded from cortical and motor neurons using HD-MEAs. The method enabled us to reconstruct up to 5-cm-long axonal arbors and directly monitor axonal conduction across thousands of recording sites. We reconstructed 1.86 m of cortical and spinal axons in total and found specific features in their structure and function.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Close Mammalian axons are specialized for transmitting action potentials to targets within the central and peripheral nervous system. A growing body of evidence suggests that, besides signal conduction, axons play essential roles in neural information processing, and their malfunctions are common hallmarks of neurodegenerative diseases. The technologies available to study axonal function and structure integrally limit the comprehension of axon neurobiology. High-density microelectrode arrays (HD-MEAs) allow for accessing axonal action potentials at high spatiotemporal resolution, but provide no insights on axonal morphology. Here, we demonstrate a method for electrical visualization of axonal morphologies based on extracellular action potentials recorded from cortical and motor neurons using HD-MEAs. The method enabled us to reconstruct up to 5-cm-long axonal arbors and directly monitor axonal conduction across thousands of recording sites. We reconstructed 1.86 m of cortical and spinal axons in total and found specific features in their structure and function. Close https://elifesciences.org/articles/86512 doi:https://doi.org/10.7554/eLife.86512 Close
69.	Duru, Jens; Maurer, Benedikt; Doran, Ciara Giles; Jelitto, Robert; Küchler, Joël; Ihle, Stephan J; Ruff, Tobias; John, Robert; Genocchi, Barbara; Vörös, János: Investigation of the input-output relationship of engineered neural networks using high-density microelectrode arrays. In: Biosensors and Bioelectronics, 2023. (Type: Journal Article \| Abstract \| Links \| BibTeX) @article{Duru2023b, title = {Investigation of the input-output relationship of engineered neural networks using high-density microelectrode arrays}, author = {Jens Duru and Benedikt Maurer and Ciara Giles Doran and Robert Jelitto and Joël Küchler and Stephan J. Ihle and Tobias Ruff and Robert John and Barbara Genocchi and János Vörös }, url = {https://www.sciencedirect.com/science/article/pii/S095656632300533X?via%3Dihub}, doi = {https://doi.org/10.1016/j.bios.2023.115591}, year = {2023}, date = {2023-08-18}, journal = {Biosensors and Bioelectronics}, abstract = {Bottom-up neuroscience utilizes small, engineered biological neural networks to study neuronal activity in systems of reduced complexity. We present a platform that establishes up to six independent networks formed by primary rat neurons on planar complementary metal–oxide–semiconductor (CMOS) microelectrode arrays (MEAs). We introduce an approach that allows repetitive stimulation and recording of network activity at any of the over 700 electrodes underlying a network. We demonstrate that the continuous application of a repetitive super-threshold stimulus yields a reproducible network answer within a 15 ms post-stimulus window. This response can be tracked with high spatiotemporal resolution across the whole extent of the network. Moreover, we show that the location of the stimulation plays a significant role in the networks' early response to the stimulus. By applying a stimulation pattern to all network-underlying electrodes in sequence, the sensitivity of the whole network to the stimulus can be visualized. We demonstrate that microchannels reduce the voltage stimulation threshold and induce the strongest network response. By varying the stimulation amplitude and frequency we reveal discrete network transition points. Finally, we introduce vector fields to follow stimulation-induced spike propagation pathways within the network. Overall we show that our defined neural networks on CMOS MEAs enable us to elicit highly reproducible activity patterns that can be precisely modulated by stimulation amplitude, stimulation frequency and the site of stimulation.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Close Bottom-up neuroscience utilizes small, engineered biological neural networks to study neuronal activity in systems of reduced complexity. We present a platform that establishes up to six independent networks formed by primary rat neurons on planar complementary metal–oxide–semiconductor (CMOS) microelectrode arrays (MEAs). We introduce an approach that allows repetitive stimulation and recording of network activity at any of the over 700 electrodes underlying a network. We demonstrate that the continuous application of a repetitive super-threshold stimulus yields a reproducible network answer within a 15 ms post-stimulus window. This response can be tracked with high spatiotemporal resolution across the whole extent of the network. Moreover, we show that the location of the stimulation plays a significant role in the networks' early response to the stimulus. By applying a stimulation pattern to all network-underlying electrodes in sequence, the sensitivity of the whole network to the stimulus can be visualized. We demonstrate that microchannels reduce the voltage stimulation threshold and induce the strongest network response. By varying the stimulation amplitude and frequency we reveal discrete network transition points. Finally, we introduce vector fields to follow stimulation-induced spike propagation pathways within the network. Overall we show that our defined neural networks on CMOS MEAs enable us to elicit highly reproducible activity patterns that can be precisely modulated by stimulation amplitude, stimulation frequency and the site of stimulation. Close https://www.sciencedirect.com/science/article/pii/S095656632300533X?via%3Dihub doi:https://doi.org/10.1016/j.bios.2023.115591 Close
70.	Ulusan, Hasan; Diggelmann, Roland; Bartram, Julian; Magnan, Chloe; Kumar, Sreedhar; Hierlemann, Andreas: Multi-Functional HD-MEA Platform for High-Resolution Impedance Imaging and Electrophysiological Recordings of Brain Slices. 2023 IEEE BioSensors Conference (BioSensors), IEEE, 2023, ISBN: 9798350346046. (Type: Conference \| Abstract \| Links \| BibTeX) @conference{Ulusan2023, title = {Multi-Functional HD-MEA Platform for High-Resolution Impedance Imaging and Electrophysiological Recordings of Brain Slices}, author = {Hasan Ulusan and Roland Diggelmann and Julian Bartram and Chloe Magnan and Sreedhar Kumar and Andreas Hierlemann}, url = {https://ieeexplore.ieee.org/document/10280868/}, doi = {10.1109/BioSensors58001.2023.10280868}, isbn = {9798350346046}, year = {2023}, date = {2023-07-30}, booktitle = {2023 IEEE BioSensors Conference (BioSensors)}, pages = {1-4}, publisher = {IEEE}, abstract = {We present a high-resolution impedance imaging and electrophysiological recording platform and demonstrate its capabilities with brain slices. The platform is easy to operate featuring an efficient data acquisition system and user-friendly software that runs on a host computer. The data acquisi tion platform relies on an FPGA system that enable s bidirectional communication between the host computer and the high-density microelectrode array (HD-MEA). The software on the host computer helps to record and online visuali ze the HD -MEA data. Moreover, online filtering (and spike detection ) features rapid visual feedback t hat enables the experimenter to reconfigure the HD -MEA. The platform includes a custom designed pressing device to affix the brain slice on the HD-MEA and maintain good electrode-tissue contact. We validated the system with mouse acute cerebellar brain slices; high-resolution impedance imaging and electrophysiological recordings yielded data that were consistent with optical imaging. Moreover, the platform enabled the selection of highly active regions for recordings with high-density configuration s and monitor multiple neurons in the same area at single-cell resolution.}, keywords = {}, pubstate = {published}, tppubtype = {conference} } Close We present a high-resolution impedance imaging and electrophysiological recording platform and demonstrate its capabilities with brain slices. The platform is easy to operate featuring an efficient data acquisition system and user-friendly software that runs on a host computer. The data acquisi tion platform relies on an FPGA system that enable s bidirectional communication between the host computer and the high-density microelectrode array (HD-MEA). The software on the host computer helps to record and online visuali ze the HD -MEA data. Moreover, online filtering (and spike detection ) features rapid visual feedback t hat enables the experimenter to reconfigure the HD -MEA. The platform includes a custom designed pressing device to affix the brain slice on the HD-MEA and maintain good electrode-tissue contact. We validated the system with mouse acute cerebellar brain slices; high-resolution impedance imaging and electrophysiological recordings yielded data that were consistent with optical imaging. Moreover, the platform enabled the selection of highly active regions for recordings with high-density configuration s and monitor multiple neurons in the same area at single-cell resolution. Close https://ieeexplore.ieee.org/document/10280868/ doi:10.1109/BioSensors58001.2023.10280868 Close
71.	Miyahara, Yuki; Shimba, Kenta; Kotani, Kiyoshi; Jimbo, Yasuhiko: Development of a Hypersensitivity Evaluation Method for Cultured Sensory Neurons Using Electrical Activity Recording. IEEE EMBC 2023 2023. (Type: Conference \| Abstract \| Links \| BibTeX) @conference{Miyahara2023, title = {Development of a Hypersensitivity Evaluation Method for Cultured Sensory Neurons Using Electrical Activity Recording}, author = {Yuki Miyahara and Kenta Shimba and Kiyoshi Kotani and Yasuhiko Jimbo}, url = {https://arinex.com.au/EMBC/pdf/full-paper_363.pdf}, year = {2023}, date = {2023-07-27}, organization = {IEEE EMBC 2023}, abstract = {Investigation of hypersensitivity caused by peripheral sensitization progression is important for developing novel pain treatments. Existing methods cannot record plastic changes in neuronal activity because they occur over a few days. We aimed to establish an efficient method to evaluate neuronal activity alterations caused by peripheral sensitization on highdensity microelectrode arrays (HD-MEAs) which can record neuronal activity for a long time. Rat dorsal root ganglion (DRG) neurons were dissected from rat embryos and cultured on HDMEAs. DRG neurons were labeled with NeuO, live staining dye. Neurons were detected with the fluorescence signal and electrodes were selected with the fluorescence images. The number of DRG neurons, whose activity were recorded, detected based on fluorescence observation was five times greater than that based on neuronal activity. Analysis of changes in neuronal activity observed in pharmacological stimulation experiments suggested that substance P induced peripheral sensitization and enhanced capsaicin sensitivity. In addition, results of immunofluorescence staining suggested that peripheral sensitization occurred mostly in neurons that co-expressed transient receptor potential vanilloid 1 (TRPV1) and neurokinin 1 receptor (NK1R). In conclusion, we established an efficient method for assessing the effects of peripheral sensitization on DRG neurons cultured on HD-MEAs.}, keywords = {}, pubstate = {published}, tppubtype = {conference} } Close Investigation of hypersensitivity caused by peripheral sensitization progression is important for developing novel pain treatments. Existing methods cannot record plastic changes in neuronal activity because they occur over a few days. We aimed to establish an efficient method to evaluate neuronal activity alterations caused by peripheral sensitization on highdensity microelectrode arrays (HD-MEAs) which can record neuronal activity for a long time. Rat dorsal root ganglion (DRG) neurons were dissected from rat embryos and cultured on HDMEAs. DRG neurons were labeled with NeuO, live staining dye. Neurons were detected with the fluorescence signal and electrodes were selected with the fluorescence images. The number of DRG neurons, whose activity were recorded, detected based on fluorescence observation was five times greater than that based on neuronal activity. Analysis of changes in neuronal activity observed in pharmacological stimulation experiments suggested that substance P induced peripheral sensitization and enhanced capsaicin sensitivity. In addition, results of immunofluorescence staining suggested that peripheral sensitization occurred mostly in neurons that co-expressed transient receptor potential vanilloid 1 (TRPV1) and neurokinin 1 receptor (NK1R). In conclusion, we established an efficient method for assessing the effects of peripheral sensitization on DRG neurons cultured on HD-MEAs. Close https://arinex.com.au/EMBC/pdf/full-paper_363.pdf Close
72.	Akita, Dai; Suwa, Eisuke; Ikeda, Narumitsu; Takahashi, Hirokazu: Neural Activity and Information Processing Capacity of Neuronal Culture. IEEE EMBC 2023 2023. (Type: Conference \| Abstract \| Links \| BibTeX) @conference{Akita2023, title = {Neural Activity and Information Processing Capacity of Neuronal Culture}, author = {Dai Akita and Eisuke Suwa and Narumitsu Ikeda and Hirokazu Takahashi}, url = {https://arinex.com.au/EMBC/pdf/full-paper_654.pdf}, year = {2023}, date = {2023-07-27}, organization = {IEEE EMBC 2023}, abstract = {Whether artificial or living, neural networks perform tremendously diverse kinds of information processing, such as visual feature extraction, speech recognition, motor control, and so on. Some studies have evaluated the computational ability of living neural networks based on the performances of specific tasks, yet could not comprehensively grasp the versatile ability. In this study, we investigated dissociated culture of neurons as a physical reservoir, which generates diverse outputs through linear regression, or readout, of the dynamical states. Based on the theory of reservoir computing, the potential computational capabilities of neuronal culture were evaluated by the information processing capacity (IPC), which indicates how a target function can be achieved from the given dynamics. As a result, we found that the neuronal culture exhibited significant IPC and that IPC varied with the inter-step interval (ISI), the time step of reservoir computing. The cultures exhibited a memory capacity of 10 time steps for computation, and this memory capacity decayed at an ISI of 5 ms or shorter. In addition, the IPC had a significant positive correlation with the intensity of the evoked response relative to spontaneous activity. The multiple regression model with evoked response and ISI showed the positive effect of evoked response and 30 ms as the best ISI for IPC. These results suggest that the distinct evoked response and the optimal time step to interact with the neuronal culture are key factors to uncover computational resources from the neuronal system.}, keywords = {}, pubstate = {published}, tppubtype = {conference} } Close Whether artificial or living, neural networks perform tremendously diverse kinds of information processing, such as visual feature extraction, speech recognition, motor control, and so on. Some studies have evaluated the computational ability of living neural networks based on the performances of specific tasks, yet could not comprehensively grasp the versatile ability. In this study, we investigated dissociated culture of neurons as a physical reservoir, which generates diverse outputs through linear regression, or readout, of the dynamical states. Based on the theory of reservoir computing, the potential computational capabilities of neuronal culture were evaluated by the information processing capacity (IPC), which indicates how a target function can be achieved from the given dynamics. As a result, we found that the neuronal culture exhibited significant IPC and that IPC varied with the inter-step interval (ISI), the time step of reservoir computing. The cultures exhibited a memory capacity of 10 time steps for computation, and this memory capacity decayed at an ISI of 5 ms or shorter. In addition, the IPC had a significant positive correlation with the intensity of the evoked response relative to spontaneous activity. The multiple regression model with evoked response and ISI showed the positive effect of evoked response and 30 ms as the best ISI for IPC. These results suggest that the distinct evoked response and the optimal time step to interact with the neuronal culture are key factors to uncover computational resources from the neuronal system. Close https://arinex.com.au/EMBC/pdf/full-paper_654.pdf Close
73.	Yamamoto, Hideaki; Hirano-Iwata, Ayumi; Sato, Shigeo: Microfluidic technologies for reconstituting neuronal network functions in vitro. In: JSAP Review, 2023. (Type: Journal Article \| Abstract \| Links \| BibTeX) @article{Yamamoto2023, title = {Microfluidic technologies for reconstituting neuronal network functions in vitro}, author = {Hideaki Yamamoto and Ayumi Hirano-Iwata and Shigeo Sato}, url = {https://www.jstage.jst.go.jp/article/oubutsu/92/5/92_278/_article/-char/en}, doi = {10.11470/oubutsu.92.5_278}, year = {2023}, date = {2023-07-06}, journal = {JSAP Review}, abstract = {The structure and function of complex neuronal networks in the brain can be partially reconstituted in vitro by integrating cell culture and microfluidic device technologies. In this report, we review our recent studies on developing microfluidic devices to reconstitute small neuronal networks bearing a modular structure, which is a canonical structure found in the nervous systems of animals. We also describe the process of recording functional activity from the reconstituted neuronal networks. These fundamental technologies offer novel tools for investigating structure–function relationships in living neuronal networks and exploring the physical basis of biological computing in the brain.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Close The structure and function of complex neuronal networks in the brain can be partially reconstituted in vitro by integrating cell culture and microfluidic device technologies. In this report, we review our recent studies on developing microfluidic devices to reconstitute small neuronal networks bearing a modular structure, which is a canonical structure found in the nervous systems of animals. We also describe the process of recording functional activity from the reconstituted neuronal networks. These fundamental technologies offer novel tools for investigating structure–function relationships in living neuronal networks and exploring the physical basis of biological computing in the brain. Close https://www.jstage.jst.go.jp/article/oubutsu/92/5/92_278/_article/-char/en doi:10.11470/oubutsu.92.5_278 Close
74.	McSweeney, Danny; English, Jay; Howell, Ethan; Ribbe, Fumiko; Pak, ChangHui: Measuring Neuronal Network Activity Using Human Induced Neuronal Cells - Stem Cell-Based Neural Model Systems for Brain Disorders. In: Methods in Molecular Biology, 2023. (Type: Book Chapter \| Abstract \| Links \| BibTeX) @inbook{McSweeney2023, title = {Measuring Neuronal Network Activity Using Human Induced Neuronal Cells - Stem Cell-Based Neural Model Systems for Brain Disorders}, author = {Danny McSweeney and Jay English and Ethan Howell and Fumiko Ribbe and ChangHui Pak}, url = {https://link.springer.com/protocol/10.1007/978-1-0716-3287-1_19}, year = {2023}, date = {2023-06-11}, publisher = {Methods in Molecular Biology}, abstract = {Synchronous firing of neurons, often referred to as “network activity” or “network bursting,” is an indication of a mature and synaptically connected network of neurons. We previously reported this phenomenon in 2D human neuronal in vitro models (McSweeney et al. iScience 25:105187, 2022). Using induced neurons (iNs) differentiated from human pluripotent stem cells (hPSCs) coupled with high-density microelectrodes arrays (HD-MEAs), we probed the underlying patterns of neuronal activity and found irregularities in network signaling across mutant states (McSweeney et al. iScience 25:105187, 2022). Here, we describe methods for plating cortical excitatory iNs differentiated from hPSCs on top of HD-MEAs and culturing iNs to maturity, examples of representative human wild-type Ngn2-iN data, and troubleshooting tips and tricks for the experimenter interested in integrating HD-MEAs into one’s research approach.}, keywords = {}, pubstate = {published}, tppubtype = {inbook} } Close Synchronous firing of neurons, often referred to as “network activity” or “network bursting,” is an indication of a mature and synaptically connected network of neurons. We previously reported this phenomenon in 2D human neuronal in vitro models (McSweeney et al. iScience 25:105187, 2022). Using induced neurons (iNs) differentiated from human pluripotent stem cells (hPSCs) coupled with high-density microelectrodes arrays (HD-MEAs), we probed the underlying patterns of neuronal activity and found irregularities in network signaling across mutant states (McSweeney et al. iScience 25:105187, 2022). Here, we describe methods for plating cortical excitatory iNs differentiated from hPSCs on top of HD-MEAs and culturing iNs to maturity, examples of representative human wild-type Ngn2-iN data, and troubleshooting tips and tricks for the experimenter interested in integrating HD-MEAs into one’s research approach. Close https://link.springer.com/protocol/10.1007/978-1-0716-3287-1_19 Close
75.	Zhao, Eric T; Hull, Jacob M; Hemed, Nofar Mintz; Ulusan, Hasan; Bartram, Julian; Zhang, Anqi; Wang, Pingyu; Pham, Albert; Silvia Ronchi, John Huguenard R; Hierlemann, Andreas; Melosh, Nicholas A: A CMOS-based highly scalable flexible neural electrode interface. In: Science Advances, 2023. (Type: Journal Article \| Abstract \| Links \| BibTeX) @article{Zhao2023, title = {A CMOS-based highly scalable flexible neural electrode interface}, author = {Eric T. Zhao and Jacob M. Hull and Nofar Mintz Hemed and Hasan Ulusan and Julian Bartram and Anqi Zhang and Pingyu Wang and Albert Pham and Silvia Ronchi, John R. Huguenard and Andreas Hierlemann and Nicholas A. Melosh}, url = {https://www.science.org/doi/10.1126/sciadv.adf9524}, doi = {DOI: 10.1126/sciadv.adf9524}, year = {2023}, date = {2023-06-07}, journal = {Science Advances}, abstract = {Perception, thoughts, and actions are encoded by the coordinated activity of large neuronal populations spread over large areas. However, existing electrophysiological devices are limited by their scalability in capturing this cortex-wide activity. Here, we developed an electrode connector based on an ultra-conformable thin-film electrode array that self-assembles onto silicon microelectrode arrays enabling multithousand channel counts at a millimeter scale. The interconnects are formed using microfabricated electrode pads suspended by thin support arms, termed Flex2Chip. Capillary-assisted assembly drives the pads to deform toward the chip surface, and van der Waals forces maintain this deformation, establishing Ohmic contact. Flex2Chip arrays successfully measured extracellular action potentials ex vivo and resolved micrometer scale seizure propagation trajectories in epileptic mice. We find that seizure dynamics in absence epilepsy in the Scn8a+/− model do not have constant propagation trajectories.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Close Perception, thoughts, and actions are encoded by the coordinated activity of large neuronal populations spread over large areas. However, existing electrophysiological devices are limited by their scalability in capturing this cortex-wide activity. Here, we developed an electrode connector based on an ultra-conformable thin-film electrode array that self-assembles onto silicon microelectrode arrays enabling multithousand channel counts at a millimeter scale. The interconnects are formed using microfabricated electrode pads suspended by thin support arms, termed Flex2Chip. Capillary-assisted assembly drives the pads to deform toward the chip surface, and van der Waals forces maintain this deformation, establishing Ohmic contact. Flex2Chip arrays successfully measured extracellular action potentials ex vivo and resolved micrometer scale seizure propagation trajectories in epileptic mice. We find that seizure dynamics in absence epilepsy in the Scn8a+/− model do not have constant propagation trajectories. Close https://www.science.org/doi/10.1126/sciadv.adf9524 doi:DOI: 10.1126/sciadv.adf9524 Close
76.	Girardi, Gregory; Zumpano, Danielle; Goshi, Noah; Raybould, Helen; Seker, Erkin: Cultured Vagal Afferent Neurons as Sensors for Intestinal Effector Molecules. In: biosensors, 2023. (Type: Journal Article \| Abstract \| Links \| BibTeX) @article{Girardi2023, title = {Cultured Vagal Afferent Neurons as Sensors for Intestinal Effector Molecules}, author = {Gregory Girardi and Danielle Zumpano and Noah Goshi and Helen Raybould and Erkin Seker}, url = {https://www.mdpi.com/2079-6374/13/6/601}, doi = {10.3390/bios13060601}, year = {2023}, date = {2023-05-31}, journal = {biosensors}, abstract = {The gut–brain axis embodies the bi-directional communication between the gastrointestinal tract and the central nervous system (CNS), where vagal afferent neurons (VANs) serve as sensors for a variety of gut-derived signals. The gut is colonized by a large and diverse population of microorganisms that communicate via small (effector) molecules, which also act on the VAN terminals situated in the gut viscera and consequently influence many CNS processes. However, the convoluted in vivo environment makes it difficult to study the causative impact of the effector molecules on VAN activation or desensitization. Here, we report on a VAN culture and its proof-of-principle demonstration as a cell-based sensor to monitor the influence of gastrointestinal effector molecules on neuronal behavior. We initially compared the effect of surface coatings (poly-L-lysine vs. Matrigel) and culture media composition (serum vs. growth factor supplement) on neurite growth as a surrogate of VAN regeneration following tissue harvesting, where the Matrigel coating, but not the media composition, played a significant role in the increased neurite growth. We then used both live-cell calcium imaging and extracellular electrophysiological recordings to show that the VANs responded to classical effector molecules of endogenous and exogenous origin (cholecystokinin serotonin and capsaicin) in a complex fashion. We expect this study to enable platforms for screening various effector molecules and their influence on VAN activity, assessed by their information-rich electrophysiological fingerprints.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Close The gut–brain axis embodies the bi-directional communication between the gastrointestinal tract and the central nervous system (CNS), where vagal afferent neurons (VANs) serve as sensors for a variety of gut-derived signals. The gut is colonized by a large and diverse population of microorganisms that communicate via small (effector) molecules, which also act on the VAN terminals situated in the gut viscera and consequently influence many CNS processes. However, the convoluted in vivo environment makes it difficult to study the causative impact of the effector molecules on VAN activation or desensitization. Here, we report on a VAN culture and its proof-of-principle demonstration as a cell-based sensor to monitor the influence of gastrointestinal effector molecules on neuronal behavior. We initially compared the effect of surface coatings (poly-L-lysine vs. Matrigel) and culture media composition (serum vs. growth factor supplement) on neurite growth as a surrogate of VAN regeneration following tissue harvesting, where the Matrigel coating, but not the media composition, played a significant role in the increased neurite growth. We then used both live-cell calcium imaging and extracellular electrophysiological recordings to show that the VANs responded to classical effector molecules of endogenous and exogenous origin (cholecystokinin serotonin and capsaicin) in a complex fashion. We expect this study to enable platforms for screening various effector molecules and their influence on VAN activity, assessed by their information-rich electrophysiological fingerprints. Close https://www.mdpi.com/2079-6374/13/6/601 doi:10.3390/bios13060601 Close
77.	Bartram, Julian; Franke, Felix; Kumar, Sreedhar Saseendran; Buccino, Alessio Paolo; Xue, Xiaohan; Gänswein, Tobias; Schröter, Manuel; Kim, Taehoon; Kasuba, Krishna Chaitanya; Hierlemann, Andreas: Parallel reconstruction of the excitatory and inhibitory inputs received by single neurons reveals the synaptic basis of recurrent spiking. In: eLife, 2023. (Type: Journal Article \| Abstract \| Links \| BibTeX) @article{Bartram2023b, title = {Parallel reconstruction of the excitatory and inhibitory inputs received by single neurons reveals the synaptic basis of recurrent spiking}, author = {Julian Bartram and Felix Franke and Sreedhar Saseendran Kumar and Alessio Paolo Buccino and Xiaohan Xue and Tobias Gänswein and Manuel Schröter and Taehoon Kim and Krishna Chaitanya Kasuba and Andreas Hierlemann}, url = {https://elifesciences.org/reviewed-preprints/86820}, doi = {10.7554/eLife.86820}, year = {2023}, date = {2023-05-17}, journal = {eLife}, abstract = {Self-sustained recurrent activity in cortical networks is thought to be important for multiple crucial processes, including circuit development and homeostasis. Yet, the precise relationship between the synaptic input patterns and the spiking output of individual neurons remains largely unresolved. Here, we developed, validated and applied a novel in vitro experimental platform and analytical procedures that provide – for individual neurons – simultaneous excitatory and inhibitory synaptic activity estimates during recurrent network activity. Our approach combines whole-network high-density microelectrode array (HD-MEA) recordings from rat neuronal cultures with patch clamping and enables a comprehensive mapping and characterization of active incoming connections to single postsynaptic neurons. We found that, during network states with excitation(E)-inhibition(I) balance, postsynaptic spiking coincided precisely with the maxima of fast fluctuations in the input E/I ratio. These spike-associated E/I ratio escalations were largely due to a rapid bidirectional change in synaptic inhibition that was modulated by the network-activity level. Our approach also uncovered the underlying circuit architecture and we show that individual neurons received a few key inhibitory connections – often from special hub neurons – that were instrumental in controlling postsynaptic spiking. Balanced network theory predicts dynamical regimes governed by small and rapid input fluctuation and featuring a fast neuronal responsiveness. Our findings – obtained in self-organized neuronal cultures – suggest that the emergence of these favorable regimes and associated network architectures is an inherent property of cortical networks in general.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Close Self-sustained recurrent activity in cortical networks is thought to be important for multiple crucial processes, including circuit development and homeostasis. Yet, the precise relationship between the synaptic input patterns and the spiking output of individual neurons remains largely unresolved. Here, we developed, validated and applied a novel in vitro experimental platform and analytical procedures that provide – for individual neurons – simultaneous excitatory and inhibitory synaptic activity estimates during recurrent network activity. Our approach combines whole-network high-density microelectrode array (HD-MEA) recordings from rat neuronal cultures with patch clamping and enables a comprehensive mapping and characterization of active incoming connections to single postsynaptic neurons. We found that, during network states with excitation(E)-inhibition(I) balance, postsynaptic spiking coincided precisely with the maxima of fast fluctuations in the input E/I ratio. These spike-associated E/I ratio escalations were largely due to a rapid bidirectional change in synaptic inhibition that was modulated by the network-activity level. Our approach also uncovered the underlying circuit architecture and we show that individual neurons received a few key inhibitory connections – often from special hub neurons – that were instrumental in controlling postsynaptic spiking. Balanced network theory predicts dynamical regimes governed by small and rapid input fluctuation and featuring a fast neuronal responsiveness. Our findings – obtained in self-organized neuronal cultures – suggest that the emergence of these favorable regimes and associated network architectures is an inherent property of cortical networks in general. Close https://elifesciences.org/reviewed-preprints/86820 doi:10.7554/eLife.86820 Close
78.	Duru, Jens; Maurer, Benedikt; Doran, Ciara Giles; Jelitto, Robert; Küchler, Joël; Ihle, Stephan J; Ruff, Tobias; John, Robert; Genocchi, Barbara; Vörös, János: Investigation of the input-output relationship of engineered neural networks using high-density microelectrode arrays. In: SSRN, 2023. (Type: Journal Article \| Abstract \| Links \| BibTeX) @article{Duru2023, title = {Investigation of the input-output relationship of engineered neural networks using high-density microelectrode arrays}, author = {Jens Duru and Benedikt Maurer and Ciara Giles Doran and Robert Jelitto and Joël Küchler and Stephan J. Ihle and Tobias Ruff and Robert John and Barbara Genocchi and János Vörös}, url = {https://www.ssrn.com/abstract=4427959}, doi = {DOI: 10.2139/ssrn.4427959}, year = {2023}, date = {2023-04-24}, journal = {SSRN}, abstract = {Bottom-up neuroscience utilizes small, engineered biological neural networks to study neuronal activity in systems of reduced complexity. We present a platform that establishes up to six independent networks formed by primary rat neurons on planar complementary metal–oxide–semiconductor (CMOS) microelectrode arrays (MEAs). We introduce an approach that allows repetitive stimulation and recording of network activity at any of the over 700 electrodes underlying a network. We demonstrate that the continuous application of a repetitive super-threshold stimulus yields a reproducible network answer within a 15 ms post-stimulus window. This response can be tracked with high spatiotemporal resolution across the whole extent of the network. Moreover, we show that the location of the stimulation plays a significant role in the networks’ early response to the stimulus. By applying a stimulation pattern to all network-underlying electrodes in sequence, the sensitivity of the whole network to the stimulus can be visualized. We demonstrate that microchannels reduce the voltage stimulation threshold and induce the strongest network response. By varying the stimulation amplitude and frequency we reveal discrete network transition points. Finally, we introduce vector fields to follow stimulation-induced spike propagation pathways within the network. Overall we show that our defined neural networks on CMOS MEAs enable us to elicit highly reproducible activity patterns that can be precisely modulated by stimulation amplitude, stimulation frequency and the site of stimulation.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Close Bottom-up neuroscience utilizes small, engineered biological neural networks to study neuronal activity in systems of reduced complexity. We present a platform that establishes up to six independent networks formed by primary rat neurons on planar complementary metal–oxide–semiconductor (CMOS) microelectrode arrays (MEAs). We introduce an approach that allows repetitive stimulation and recording of network activity at any of the over 700 electrodes underlying a network. We demonstrate that the continuous application of a repetitive super-threshold stimulus yields a reproducible network answer within a 15 ms post-stimulus window. This response can be tracked with high spatiotemporal resolution across the whole extent of the network. Moreover, we show that the location of the stimulation plays a significant role in the networks’ early response to the stimulus. By applying a stimulation pattern to all network-underlying electrodes in sequence, the sensitivity of the whole network to the stimulus can be visualized. We demonstrate that microchannels reduce the voltage stimulation threshold and induce the strongest network response. By varying the stimulation amplitude and frequency we reveal discrete network transition points. Finally, we introduce vector fields to follow stimulation-induced spike propagation pathways within the network. Overall we show that our defined neural networks on CMOS MEAs enable us to elicit highly reproducible activity patterns that can be precisely modulated by stimulation amplitude, stimulation frequency and the site of stimulation. Close https://www.ssrn.com/abstract=4427959 doi:DOI: 10.2139/ssrn.4427959 Close
79.	Cerina, Marta; Piastra, Maria Carla; Frega, Monica: The potential of in vitro neuronal networks cultured on Micro Electrode Arrays for biomedical research. In: Progress in Biomedical Engineering, 2023. (Type: Journal Article \| Abstract \| Links \| BibTeX) @article{Cerina2023, title = {The potential of in vitro neuronal networks cultured on Micro Electrode Arrays for biomedical research}, author = {Marta Cerina and Maria Carla Piastra and Monica Frega}, url = {https://iopscience.iop.org/article/10.1088/2516-1091/acce12}, doi = {10.1088/2516-1091/acce12}, year = {2023}, date = {2023-04-18}, journal = {Progress in Biomedical Engineering}, abstract = {In vitro neuronal models have become an important tool to study healthy and diseased neuronal circuits. The growing interest of neuroscientists to explore the dynamics of neuronal systems and the increasing need to observe, measure and manipulate not only single neurons but populations of cells pushed for technological advancement. In this sense, Micro-Electrode Arrays (MEAs) emerged as a promising technique, made of cell culture dishes with embedded micro-electrodes allowing non-invasive and relatively simple measurement of the activity of neuronal cultures at the network level. In the past decade, MEAs popularity has rapidly grown. MEA devices have been extensively used to measure the activity of neuronal cultures mainly derived from rodents. Rodent neuronal cultures on MEAs have been employed to investigate physiological mechanisms, study the effect of chemicals in neurotoxicity screenings, and model the electrophysiological phenotype of neuronal networks in different pathological conditions. With the advancements in human induced pluripotent stem cells (hiPSCs) technology, the differentiation of human neurons from the cells of adult donors became possible. hiPSCsderived neuronal networks on MEAs have been employed to develop patient-specific in vitro platforms to characterize the pathophysiological phenotype and to test drugs, paving the way towards personalized medicine. In this review, we first describe MEA technology and the information that can be obtained from MEA recordings. Then, we give an overview of studies in which MEAs have been used in combination with different neuronal systems (i.e., rodent 2D and 3D neuronal cultures, organotypic brain slices, hiPSCs-derived 2D and 3D neuronal cultures, and brain organoids) for biomedical research, including physiology studies, neurotoxicity screenings, disease modeling, and drug testing. We end by discussing potential, challenges and future perspectives of MEA technology, and providing some guidance for the choice of the neuronal model and MEA device, experimental design, data analysis and reporting for scientific publications.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Close In vitro neuronal models have become an important tool to study healthy and diseased neuronal circuits. The growing interest of neuroscientists to explore the dynamics of neuronal systems and the increasing need to observe, measure and manipulate not only single neurons but populations of cells pushed for technological advancement. In this sense, Micro-Electrode Arrays (MEAs) emerged as a promising technique, made of cell culture dishes with embedded micro-electrodes allowing non-invasive and relatively simple measurement of the activity of neuronal cultures at the network level. In the past decade, MEAs popularity has rapidly grown. MEA devices have been extensively used to measure the activity of neuronal cultures mainly derived from rodents. Rodent neuronal cultures on MEAs have been employed to investigate physiological mechanisms, study the effect of chemicals in neurotoxicity screenings, and model the electrophysiological phenotype of neuronal networks in different pathological conditions. With the advancements in human induced pluripotent stem cells (hiPSCs) technology, the differentiation of human neurons from the cells of adult donors became possible. hiPSCsderived neuronal networks on MEAs have been employed to develop patient-specific in vitro platforms to characterize the pathophysiological phenotype and to test drugs, paving the way towards personalized medicine. In this review, we first describe MEA technology and the information that can be obtained from MEA recordings. Then, we give an overview of studies in which MEAs have been used in combination with different neuronal systems (i.e., rodent 2D and 3D neuronal cultures, organotypic brain slices, hiPSCs-derived 2D and 3D neuronal cultures, and brain organoids) for biomedical research, including physiology studies, neurotoxicity screenings, disease modeling, and drug testing. We end by discussing potential, challenges and future perspectives of MEA technology, and providing some guidance for the choice of the neuronal model and MEA device, experimental design, data analysis and reporting for scientific publications. Close https://iopscience.iop.org/article/10.1088/2516-1091/acce12 doi:10.1088/2516-1091/acce12 Close
80.	Xu, He Jax; Yao, Yao; Yao, Fenyong; Chen, Jiehui; Li, Meishi; Yang, Xianfa; Li, Sheng; Lu, Fangru; Hu, Ping; He, Shuijin; Peng, Guangdun; Jing, Naihe: Generation of functional posterior spinal motor neurons from hPSCs-derived human spinal cord neural progenitor cells. In: Cell Regeneration, 2023. (Type: Journal Article \| Abstract \| Links \| BibTeX) @article{Xu2023, title = {Generation of functional posterior spinal motor neurons from hPSCs-derived human spinal cord neural progenitor cells}, author = {He Jax Xu and Yao Yao and Fenyong Yao and Jiehui Chen and Meishi Li and Xianfa Yang and Sheng Li and Fangru Lu and Ping Hu and Shuijin He and Guangdun Peng and Naihe Jing}, url = {https://cellregeneration.springeropen.com/articles/10.1186/s13619-023-00159-6}, doi = {10.1186/s13619-023-00159-6}, year = {2023}, date = {2023-03-23}, journal = {Cell Regeneration}, abstract = {Spinal motor neurons deficiency results in a series of devastating disorders such as amyotrophic lateral sclerosis (ALS), spinal muscular atrophy (SMA) and spinal cord injury (SCI). These disorders are currently incurable, while human pluripotent stem cells (hPSCs)-derived spinal motor neurons are promising but suffered from inappropriate regional identity and functional immaturity for the study and treatment of posterior spinal cord related injuries. In this study, we have established human spinal cord neural progenitor cells (hSCNPCs) via hPSCs differentiated neuromesodermal progenitors (NMPs) and demonstrated the hSCNPCs can be continuously expanded up to 40 passages. hSCNPCs can be rapidly differentiated into posterior spinal motor neurons with high efficiency. The functional maturity has been examined in detail. Moreover, a co-culture scheme which is compatible for both neural and muscular differentiation is developed to mimic the neuromuscular junction (NMJ) formation in vitro. Together, these studies highlight the potential avenues for generating clinically relevant spinal motor neurons and modeling neuromuscular diseases through our defined hSCNPCs.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Close Spinal motor neurons deficiency results in a series of devastating disorders such as amyotrophic lateral sclerosis (ALS), spinal muscular atrophy (SMA) and spinal cord injury (SCI). These disorders are currently incurable, while human pluripotent stem cells (hPSCs)-derived spinal motor neurons are promising but suffered from inappropriate regional identity and functional immaturity for the study and treatment of posterior spinal cord related injuries. In this study, we have established human spinal cord neural progenitor cells (hSCNPCs) via hPSCs differentiated neuromesodermal progenitors (NMPs) and demonstrated the hSCNPCs can be continuously expanded up to 40 passages. hSCNPCs can be rapidly differentiated into posterior spinal motor neurons with high efficiency. The functional maturity has been examined in detail. Moreover, a co-culture scheme which is compatible for both neural and muscular differentiation is developed to mimic the neuromuscular junction (NMJ) formation in vitro. Together, these studies highlight the potential avenues for generating clinically relevant spinal motor neurons and modeling neuromuscular diseases through our defined hSCNPCs. Close https://cellregeneration.springeropen.com/articles/10.1186/s13619-023-00159-6 doi:10.1186/s13619-023-00159-6 Close

235 entries « ‹ 4 of 12 › »

235 entries « ‹ 4 of 5 › »

2019
	Russell, Thomas L; Zhang, Jichang; Okoniewksi, Michal; Franke, Felix; Bichet, Sandrine; Hierlemann, Andreas Medullary Respiratory Circuit Is Reorganized by a Seasonally-Induced Program in Preparation for Hibernation Journal Article Frontiers in Neuroscience , 13 , 2019, ISSN: 1662-453X. Abstract \| Links \| BibTeX \| タグ: Respiratory Circuit @article{Russell2019, title = {Medullary Respiratory Circuit Is Reorganized by a Seasonally-Induced Program in Preparation for Hibernation }, author = {Thomas L. Russell and Jichang Zhang and Michal Okoniewksi and Felix Franke and Sandrine Bichet and Andreas Hierlemann}, url = {https://www.frontiersin.org/article/10.3389/fnins.2019.00376}, doi = {10.3389/fnins.2019.00376 }, issn = {1662-453X}, year = {2019}, date = {2019-04-26}, journal = {Frontiers in Neuroscience }, volume = {13}, abstract = {Deep hibernators go through several cycles of profound drops in body temperature during the winter season, with core temperatures sometimes reaching near freezing. Yet unlike non-hibernating mammals, they can sustain breathing rhythms. The physiological processes that make this possible are still not understood. In this study, we focused on the medullary Ventral Respiratory Column of a facultative hibernator, the Syrian hamster. Using shortened day-lengths, we induced a "winter-adapted" physiological state, which is a prerequisite for hibernation. When recording electrophysiological signals from acute slices in the winter-adapted pre-Bötzinger complex, spike trains showed higher spike rates, amplitudes, complexity, as well as higher temperature sensitivity, suggesting an increase in connectivity and/or synaptic strength during the winter season. We further examined action potential waveforms and found that the depolarization integral, as measured by the area under the curve, is selectively enhanced in winter-adapted animals. This suggests that a shift in the ion handling kinetics is also being induced by the winter-adaptation program. RNA sequencing of respiratory pre-motor neurons, followed by gene set enrichment analysis, revealed differential regulation and splicing in structural, synaptic, and ion handling genes. Splice junction analysis suggested that differential exon usage is occurring in a select subset of ion handling subunits (ATP1A3, KCNC3, SCN1B), and synaptic structure genes (SNCB, SNCG, RAB3A). Our findings show that the hamster respiratory center undergoes a seasonally-cued alteration in electrophysiological properties, likely protecting against respiratory failure at low temperatures.}, keywords = {Respiratory Circuit}, pubstate = {published}, tppubtype = {article} } Close Deep hibernators go through several cycles of profound drops in body temperature during the winter season, with core temperatures sometimes reaching near freezing. Yet unlike non-hibernating mammals, they can sustain breathing rhythms. The physiological processes that make this possible are still not understood. In this study, we focused on the medullary Ventral Respiratory Column of a facultative hibernator, the Syrian hamster. Using shortened day-lengths, we induced a "winter-adapted" physiological state, which is a prerequisite for hibernation. When recording electrophysiological signals from acute slices in the winter-adapted pre-Bötzinger complex, spike trains showed higher spike rates, amplitudes, complexity, as well as higher temperature sensitivity, suggesting an increase in connectivity and/or synaptic strength during the winter season. We further examined action potential waveforms and found that the depolarization integral, as measured by the area under the curve, is selectively enhanced in winter-adapted animals. This suggests that a shift in the ion handling kinetics is also being induced by the winter-adaptation program. RNA sequencing of respiratory pre-motor neurons, followed by gene set enrichment analysis, revealed differential regulation and splicing in structural, synaptic, and ion handling genes. Splice junction analysis suggested that differential exon usage is occurring in a select subset of ion handling subunits (ATP1A3, KCNC3, SCN1B), and synaptic structure genes (SNCB, SNCG, RAB3A). Our findings show that the hamster respiratory center undergoes a seasonally-cued alteration in electrophysiological properties, likely protecting against respiratory failure at low temperatures. Close https://www.frontiersin.org/article/10.3389/fnins.2019.00376 doi:10.3389/fnins.2019.00376 Close
	Ronchi, Silvia; Fiscella, Michele; Marchetti, Camilla; Viswam, Vijay; Muller, Jan; Frey, Urs; Hierlemann, Andreas Single-Cell Electrical Stimulation Using CMOS-Based High-Density Microelectrode Arrays Journal Article Frontiers in Neuroscience, 13 , 2019, ISSN: 1662-453X . Abstract \| Links \| BibTeX \| タグ: ETH-CMOS-MEA, Stimulation @article{Ronchi2019, title = {Single-Cell Electrical Stimulation Using CMOS-Based High-Density Microelectrode Arrays}, author = {Silvia Ronchi and Michele Fiscella and Camilla Marchetti and Vijay Viswam and Jan Muller and Urs Frey and Andreas Hierlemann}, url = {https://www.frontiersin.org/article/10.3389/fnins.2019.00208 }, doi = {10.3389/fnins.2019.00208 }, issn = {1662-453X }, year = {2019}, date = {2019-03-13}, journal = {Frontiers in Neuroscience}, volume = {13}, abstract = {Non-invasive electrical stimulation can be used to study and control neural activity in the brain or to alleviate somatosensory dysfunctions. One intriguing prospect is to precisely stimulate individual targeted neurons. Here, we investigated single-neuron current and voltage stimulation in vitro using high-density microelectrode arrays featuring 26’400 bidirectional electrodes at a pitch of 17.5 µm and an electrode area of 5 × 9 µm². We determined optimal waveforms, amplitudes and durations for both stimulation modes. Owing to the high spatial resolution of our arrays and the close proximity of the electrodes to the respective neurons, we were able to stimulate the axon initial segments (AIS) with charges of less than 2 picoCoulombs. This resulted in minimal artifact production and reliable readout of stimulation efficiency directly at the soma of the stimulated cell. Stimulation signals as low as 70 mV or 100 nA,with pulse durations as short as 18 µs, yielded measurable action potential initiation and propagation. We found that the required stimulation signal amplitudes decreased with cell growth and development and that stimulation efficiency did not improve at higher electric fields generated by simultaneous multi-electrode stimulation.}, keywords = {ETH-CMOS-MEA, Stimulation}, pubstate = {published}, tppubtype = {article} } Close Non-invasive electrical stimulation can be used to study and control neural activity in the brain or to alleviate somatosensory dysfunctions. One intriguing prospect is to precisely stimulate individual targeted neurons. Here, we investigated single-neuron current and voltage stimulation in vitro using high-density microelectrode arrays featuring 26’400 bidirectional electrodes at a pitch of 17.5 µm and an electrode area of 5 × 9 µm². We determined optimal waveforms, amplitudes and durations for both stimulation modes. Owing to the high spatial resolution of our arrays and the close proximity of the electrodes to the respective neurons, we were able to stimulate the axon initial segments (AIS) with charges of less than 2 picoCoulombs. This resulted in minimal artifact production and reliable readout of stimulation efficiency directly at the soma of the stimulated cell. Stimulation signals as low as 70 mV or 100 nA,with pulse durations as short as 18 µs, yielded measurable action potential initiation and propagation. We found that the required stimulation signal amplitudes decreased with cell growth and development and that stimulation efficiency did not improve at higher electric fields generated by simultaneous multi-electrode stimulation. Close https://www.frontiersin.org/article/10.3389/fnins.2019.00208 doi:10.3389/fnins.2019.00208 Close
	Obien, Marie Engelene J; Hierlemann, Andreas; Frey, Urs Accurate signal-source localization in brain slices by means of high-density microelectrode arrays Journal Article Scientific Reports, 9 (788), 2019. Abstract \| Links \| BibTeX \| タグ: Brain Slice @article{Obien2019, title = {Accurate signal-source localization in brain slices by means of high-density microelectrode arrays}, author = {Marie Engelene J. Obien and Andreas Hierlemann and Urs Frey}, url = {https://www.nature.com/articles/s41598-018-36895-y}, doi = {10.1038/s41598-018-36895-y}, year = {2019}, date = {2019-01-28}, journal = {Scientific Reports}, volume = {9}, number = {788}, abstract = {Extracellular recordings by means of high-density microelectrode arrays (HD-MEAs) have become a powerful tool to resolve subcellular details of single neurons in active networks grown from dissociated cells. To extend the application of this technology to slice preparations, we developed models describing how extracellular signals, produced by neuronal cells in slices, are detected by microelectrode arrays. The models help to analyze and understand the electrical-potential landscape in an in vitro HD-MEA-recording scenario based on point-current sources. We employed two modeling schemes, (i) a simple analytical approach, based on the method of images (MoI), and (ii) an approach, based on finite-element methods (FEM). We compared and validated the models with large-scale, high-spatiotemporal-resolution recordings of slice preparations by means of HD-MEAs. We then developed a model-based localization algorithm and compared the performance of MoI and FEM models. Both models provided accurate localization results and a comparable and negligible systematic error, when the point source was in saline, a condition similar to cell-culture experiments. Moreover, the relative random error in the x-y-z-localization amounted only up to 4.3% for z-distances up to 200 μm from the HD-MEA surface. In tissue, the systematic errors of both, MoI and FEM models were significantly higher, and a pre-calibration was required. Nevertheless, the FEM values proved to be closer to the tissue experimental results, yielding 5.2 μm systematic mean error, compared to 22.0 μm obtained with MoI. These results suggest that the medium volume or “saline height”, the brain slice thickness and anisotropy, and the location of the reference electrode, which were included in the FEM model, considerably affect the extracellular signal and localization performance, when the signal source is at larger distance to the array. After pre-calibration, the relative random error of the z-localization in tissue was only 3% for z-distances up to 200 μm. We then applied the model and related detailed understanding of extracellular recordings to achieve an electrically-guided navigation of a stimulating micropipette, solely based on the measured HD-MEA signals, and managed to target spontaneously active neurons in an acute brain slice for electroporation.}, keywords = {Brain Slice}, pubstate = {published}, tppubtype = {article} } Close Extracellular recordings by means of high-density microelectrode arrays (HD-MEAs) have become a powerful tool to resolve subcellular details of single neurons in active networks grown from dissociated cells. To extend the application of this technology to slice preparations, we developed models describing how extracellular signals, produced by neuronal cells in slices, are detected by microelectrode arrays. The models help to analyze and understand the electrical-potential landscape in an in vitro HD-MEA-recording scenario based on point-current sources. We employed two modeling schemes, (i) a simple analytical approach, based on the method of images (MoI), and (ii) an approach, based on finite-element methods (FEM). We compared and validated the models with large-scale, high-spatiotemporal-resolution recordings of slice preparations by means of HD-MEAs. We then developed a model-based localization algorithm and compared the performance of MoI and FEM models. Both models provided accurate localization results and a comparable and negligible systematic error, when the point source was in saline, a condition similar to cell-culture experiments. Moreover, the relative random error in the x-y-z-localization amounted only up to 4.3% for z-distances up to 200 μm from the HD-MEA surface. In tissue, the systematic errors of both, MoI and FEM models were significantly higher, and a pre-calibration was required. Nevertheless, the FEM values proved to be closer to the tissue experimental results, yielding 5.2 μm systematic mean error, compared to 22.0 μm obtained with MoI. These results suggest that the medium volume or “saline height”, the brain slice thickness and anisotropy, and the location of the reference electrode, which were included in the FEM model, considerably affect the extracellular signal and localization performance, when the signal source is at larger distance to the array. After pre-calibration, the relative random error of the z-localization in tissue was only 3% for z-distances up to 200 μm. We then applied the model and related detailed understanding of extracellular recordings to achieve an electrically-guided navigation of a stimulating micropipette, solely based on the measured HD-MEA signals, and managed to target spontaneously active neurons in an acute brain slice for electroporation. Close https://www.nature.com/articles/s41598-018-36895-y doi:10.1038/s41598-018-36895-y Close
	Dudina, Alexandra; Seichepine, Florent; Chen, Yihui; and Stettler, Alexander; Hierlemann, Andreas; and Frey, Urs Monolithic CMOS sensor platform featuring an array of 9’216 carbon-nanotube-sensor elements and low-noise, wide-bandwidth and wide-dynamic-range readout circuitry Journal Article Sensors and Actuators B: Chemical, 279 , pp. 255-266, 2019. Abstract \| Links \| BibTeX \| タグ: ETH-CMOS-MEA @article{Dudina2019, title = {Monolithic CMOS sensor platform featuring an array of 9’216 carbon-nanotube-sensor elements and low-noise, wide-bandwidth and wide-dynamic-range readout circuitry}, author = {Alexandra Dudina and Florent Seichepine and Yihui Chen and and Alexander Stettler and Andreas Hierlemann and and Urs Frey}, url = {https://www.sciencedirect.com/science/article/pii/S0925400518317672?via%3Dihub}, doi = {10.1016/j.snb.2018.10.004}, year = {2019}, date = {2019-01-15}, journal = {Sensors and Actuators B: Chemical}, volume = {279}, pages = {255-266}, abstract = {We present the design and characterization of a monolithic complementary metal–oxide–semiconductor (CMOS) biosensor platform comprising of a switch-matrix-based array of 9′216 carbon nanotube field-effect transistors (CNTFETs) and associated readout circuitry. The switch-matrix allows for flexible selection and simultaneous routing of 96 sensor elements to the corresponding readout channels. A low-noise, wide-bandwidth, wide-dynamic-range transimpedance continuous-time amplifier architecture has been implemented to facilitate resistance measurements in the range between 50 kΩ and 1 GΩ at a bandwidth of up to 1 MHz. The achieved accuracy of the resistance measurements over the whole range is 4%. The system has been successfully fabricated and tested and shows a noise performance equal to 2.14 pArms at a bandwidth of 1 kHz and 0.84 nArms at a bandwidth of 1 MHz. A batch integration of the CNTFETs has been achieved by using a dielectrophoresis (DEP)–based manipulation technique. The current-voltage curves of CNTFETs have been acquired, and the sensing capabilities of the system have been demonstrated by recording resistance changes of CNTFETs upon exposure to solutions with different pH values and different concentrations of NaCl. The smallest resolvable concentrations for the respective analytes were estimated to amount to 0.025 pH-units and 4 mM NaCl.}, keywords = {ETH-CMOS-MEA}, pubstate = {published}, tppubtype = {article} } Close We present the design and characterization of a monolithic complementary metal–oxide–semiconductor (CMOS) biosensor platform comprising of a switch-matrix-based array of 9′216 carbon nanotube field-effect transistors (CNTFETs) and associated readout circuitry. The switch-matrix allows for flexible selection and simultaneous routing of 96 sensor elements to the corresponding readout channels. A low-noise, wide-bandwidth, wide-dynamic-range transimpedance continuous-time amplifier architecture has been implemented to facilitate resistance measurements in the range between 50 kΩ and 1 GΩ at a bandwidth of up to 1 MHz. The achieved accuracy of the resistance measurements over the whole range is 4%. The system has been successfully fabricated and tested and shows a noise performance equal to 2.14 pArms at a bandwidth of 1 kHz and 0.84 nArms at a bandwidth of 1 MHz. A batch integration of the CNTFETs has been achieved by using a dielectrophoresis (DEP)–based manipulation technique. The current-voltage curves of CNTFETs have been acquired, and the sensing capabilities of the system have been demonstrated by recording resistance changes of CNTFETs upon exposure to solutions with different pH values and different concentrations of NaCl. The smallest resolvable concentrations for the respective analytes were estimated to amount to 0.025 pH-units and 4 mM NaCl. Close https://www.sciencedirect.com/science/article/pii/S0925400518317672?via%3Dihub doi:10.1016/j.snb.2018.10.004 Close
	Shadmani, Amir; Viswam, Vijay; Chen, Yihui; Bounik, Raziyeh; Dragas, Jelena; Radivojevic, Milos; Geissler, Sydney; Sitnikov, Sergey; Muller, Jan; Hierlemann, Andreas Stimulation and Artifact-suppression Techniques for in-vitro High-density Microelectrode Array Systems. Journal Article IEEE Transactions on Biomedical Engineering, 2019. Abstract \| Links \| BibTeX \| タグ: ETH-CMOS-MEA @article{Shadmani2019b, title = {Stimulation and Artifact-suppression Techniques for in-vitro High-density Microelectrode Array Systems.}, author = {Amir Shadmani and Vijay Viswam and Yihui Chen and Raziyeh Bounik and Jelena Dragas and Milos Radivojevic and Sydney Geissler and Sergey Sitnikov and Jan Muller and Andreas Hierlemann }, url = {https://ieeexplore.ieee.org/document/8599003}, doi = {10.1109/TBME.2018.2890530}, year = {2019}, date = {2019-01-01}, journal = {IEEE Transactions on Biomedical Engineering}, abstract = {We present novel voltage stimulation buffers with controlled output current, along with recording circuits featuring adjustable high-pass cut-off filtering to perform efficient stimulation while actively suppressing stimulation artifacts in high-density microelectrode arrays. Owing to the dense packing and close proximity of the electrodes in such systems, a stimulation through one electrode can cause large electrical artifacts on neighboring electrodes that easily saturate the corresponding recording amplifiers. To suppress such artifacts, the high-pass corner frequencies of all available 2048 recording channels can be raised from several Hz to several kHz by applying a "soft-reset" or pole-shifting technique. With the implemented artifact suppression technique, the saturation time of the recording circuits, connected to electrodes in immediate vicinity to the stimulation site, could be reduced to less than 150μs. For the stimulation buffer, we developed a circuit, which can operate in two modes: either control of only the stimulation voltage, or control of current and voltage during stimulation. The voltage-only controlled mode employs a local common-mode feedback operational transconductance amplifier with a near rail-to-rail input/output range, suitable for driving high capacitive loads. The current/voltage controlled mode is based on a positive current conveyor generating adjustable output currents, while its upper and lower output voltages are limited by two feedback loops. The current/voltage controlled circuit can generate stimulation pulses up to 30 μA with less than ±0.1% linearity error in the low-current mode, and up to 300 μA with less than ±0.2% linearity error in the high-current mode.}, keywords = {ETH-CMOS-MEA}, pubstate = {published}, tppubtype = {article} } Close We present novel voltage stimulation buffers with controlled output current, along with recording circuits featuring adjustable high-pass cut-off filtering to perform efficient stimulation while actively suppressing stimulation artifacts in high-density microelectrode arrays. Owing to the dense packing and close proximity of the electrodes in such systems, a stimulation through one electrode can cause large electrical artifacts on neighboring electrodes that easily saturate the corresponding recording amplifiers. To suppress such artifacts, the high-pass corner frequencies of all available 2048 recording channels can be raised from several Hz to several kHz by applying a "soft-reset" or pole-shifting technique. With the implemented artifact suppression technique, the saturation time of the recording circuits, connected to electrodes in immediate vicinity to the stimulation site, could be reduced to less than 150μs. For the stimulation buffer, we developed a circuit, which can operate in two modes: either control of only the stimulation voltage, or control of current and voltage during stimulation. The voltage-only controlled mode employs a local common-mode feedback operational transconductance amplifier with a near rail-to-rail input/output range, suitable for driving high capacitive loads. The current/voltage controlled mode is based on a positive current conveyor generating adjustable output currents, while its upper and lower output voltages are limited by two feedback loops. The current/voltage controlled circuit can generate stimulation pulses up to 30 μA with less than ±0.1% linearity error in the low-current mode, and up to 300 μA with less than ±0.2% linearity error in the high-current mode. Close https://ieeexplore.ieee.org/document/8599003 doi:10.1109/TBME.2018.2890530 Close
2018
	Bakkum, Douglas J; Obien, Marie Engelene J; Radivojevic, Milos; Jäckel, David; Frey, Urs; Takahashi, Hirokazu; Hierlemann, Andreas The Axon Initial Segment is the Dominant Contributor to the Neuron's Extracellular Electrical Potential Landscape Journal Article Advanced Biosystems, 2018. Abstract \| Links \| BibTeX \| タグ: ETH-CMOS-MEA @article{Bakkum2018b, title = {The Axon Initial Segment is the Dominant Contributor to the Neuron's Extracellular Electrical Potential Landscape}, author = {Douglas J. Bakkum and Marie Engelene J. Obien and Milos Radivojevic and David Jäckel and Urs Frey and Hirokazu Takahashi and Andreas Hierlemann}, url = {https://onlinelibrary.wiley.com/doi/full/10.1002/adbi.201800308}, doi = {10.1002/adbi.201800308}, year = {2018}, date = {2018-11-29}, journal = {Advanced Biosystems}, abstract = {Extracellular voltage fields, produced by a neuron's action potentials, provide a widely used means for studying neuronal and neuronal‐network function. The neuron's soma and dendrites are thought to drive the extracellular action potential (EAP) landscape, while the axon's contribution is usually considered less important. However, by recording voltages of single neurons in dissociated rat cortical cultures and Purkinje cells in acute mouse cerebellar slices through hundreds of densely packed electrodes, it is found, instead, that the axon initial segment dominates the measured EAP landscape, and, surprisingly, the soma only contributes to a minor extent. As expected, the recorded dominant signal has negative polarity (charge entering the cell) and initiates at the distal end. Interestingly, signals with positive polarity (charge exiting the cell) occur near some but not all dendritic branches and occur after a delay. Such basic knowledge about which neuronal compartments contribute to the extracellular voltage landscape is important for interpreting results from all electrical readout schemes. Finally, initiation of the electrical activity at the distal end of the axon initial segment (AIS) and subsequent spreading into the axon proper and backward through the proximal AIS toward the soma are confirmed. The corresponding extracellular waveforms across different neuronal compartments could be tracked.}, keywords = {ETH-CMOS-MEA}, pubstate = {published}, tppubtype = {article} } Close Extracellular voltage fields, produced by a neuron's action potentials, provide a widely used means for studying neuronal and neuronal‐network function. The neuron's soma and dendrites are thought to drive the extracellular action potential (EAP) landscape, while the axon's contribution is usually considered less important. However, by recording voltages of single neurons in dissociated rat cortical cultures and Purkinje cells in acute mouse cerebellar slices through hundreds of densely packed electrodes, it is found, instead, that the axon initial segment dominates the measured EAP landscape, and, surprisingly, the soma only contributes to a minor extent. As expected, the recorded dominant signal has negative polarity (charge entering the cell) and initiates at the distal end. Interestingly, signals with positive polarity (charge exiting the cell) occur near some but not all dendritic branches and occur after a delay. Such basic knowledge about which neuronal compartments contribute to the extracellular voltage landscape is important for interpreting results from all electrical readout schemes. Finally, initiation of the electrical activity at the distal end of the axon initial segment (AIS) and subsequent spreading into the axon proper and backward through the proximal AIS toward the soma are confirmed. The corresponding extracellular waveforms across different neuronal compartments could be tracked. Close https://onlinelibrary.wiley.com/doi/full/10.1002/adbi.201800308 doi:10.1002/adbi.201800308 Close
	Viswam, Vijay; Bounik, Raziyeh; Shadmani, Amir; Dragas, Jelena; Urwyler, Cedar; Boos, Julia Alicia; Obien, Marie Engelene J; Muller, Jan; Chen, Yihui; Hierlemann, Andreas Impedance Spectroscopy and Electrophysiological Imaging of Cells With a High-Density CMOS Microelectrode Array System Journal Article IEEE Transactions on Biomedical Circuits and Systems, 12 (6), pp. 1356-1368, 2018, ISSN: 1932-4545. Abstract \| Links \| BibTeX \| タグ: HD-MEA @article{Viswam2018, title = {Impedance Spectroscopy and Electrophysiological Imaging of Cells With a High-Density CMOS Microelectrode Array System}, author = {Vijay Viswam and Raziyeh Bounik and Amir Shadmani and Jelena Dragas and Cedar Urwyler and Julia Alicia Boos and Marie Engelene J. Obien and Jan Muller and Yihui Chen and Andreas Hierlemann}, url = {https://ieeexplore.ieee.org/document/8532304}, doi = {10.1109/TBCAS.2018.2881044}, issn = {1932-4545}, year = {2018}, date = {2018-11-12}, journal = {IEEE Transactions on Biomedical Circuits and Systems}, volume = {12}, number = {6}, pages = {1356-1368}, abstract = {A monolithic multi-functional CMOS microelectrode array system was developed that enables label-free electrochemical impedance spectroscopy of cells in vitro at high spatiotemporal resolution. The electrode array includes 59,760 platinum microelectrodes, densely packed within a 4.5 mm × 2.5 mm sensing region at a pitch of 13.5 μm. A total of 32 on-chip lock-in amplifiers can be used to measure the impedance of any arbitrarily chosen subset of electrodes in the array. A sinusoidal voltage, generated by an on-chip waveform generator with a frequency range from 1 Hz to 1 MHz, was applied to the reference electrode. The sensing currents through the selected recording electrodes were amplified, demodulated, filtered, and digitized to obtain the magnitude and phase information of the respective impedances. The circuitry consumes only 412 μW at 3.3 V supply voltage and occupies only 0.1 mm 2 , for each channel. The system also included 2048 extracellular action-potential recording channels on the same chip. Proof of concept measurements of electrical impedance imaging and electrophysiology recording of cardiac cells and brain slices are demonstrated in this paper. Optical and impedance images showed a strong correlation.}, keywords = {HD-MEA}, pubstate = {published}, tppubtype = {article} } Close A monolithic multi-functional CMOS microelectrode array system was developed that enables label-free electrochemical impedance spectroscopy of cells in vitro at high spatiotemporal resolution. The electrode array includes 59,760 platinum microelectrodes, densely packed within a 4.5 mm × 2.5 mm sensing region at a pitch of 13.5 μm. A total of 32 on-chip lock-in amplifiers can be used to measure the impedance of any arbitrarily chosen subset of electrodes in the array. A sinusoidal voltage, generated by an on-chip waveform generator with a frequency range from 1 Hz to 1 MHz, was applied to the reference electrode. The sensing currents through the selected recording electrodes were amplified, demodulated, filtered, and digitized to obtain the magnitude and phase information of the respective impedances. The circuitry consumes only 412 μW at 3.3 V supply voltage and occupies only 0.1 mm 2 , for each channel. The system also included 2048 extracellular action-potential recording channels on the same chip. Proof of concept measurements of electrical impedance imaging and electrophysiology recording of cardiac cells and brain slices are demonstrated in this paper. Optical and impedance images showed a strong correlation. Close https://ieeexplore.ieee.org/document/8532304 doi:10.1109/TBCAS.2018.2881044 Close
	Lewandowska, Marta K; Bogatikov, Evgenii; Hierlemann, Andreas; Punga, Anna Rostedt Long-term high-density extracellular recordings enable studies of muscle cell physiology and pathology Conference Contribution 700.13 , Society for Neuroscience (SfN) Meeting San Diego, CA, USA, 2018. Abstract \| Links \| BibTeX \| タグ: ETH-CMOS-MEA, Physiology @conference{Lewandowska2018c, title = {Long-term high-density extracellular recordings enable studies of muscle cell physiology and pathology}, author = {Marta K. Lewandowska and Evgenii Bogatikov and Andreas Hierlemann and Anna Rostedt Punga}, url = {https://abstractsonline.com/pp8/#!/4649/presentation/24936}, year = {2018}, date = {2018-11-07}, volume = {Contribution 700.13}, address = {San Diego, CA, USA}, organization = {Society for Neuroscience (SfN) Meeting}, abstract = {Skeletal (voluntary) muscle is the most abundant tissue in the body, thus making it an important biomedical research subject. Studies of neuromuscular transmission, including disorders of defective ion channels or receptors in autoimmune or genetic neuromuscular disorders, require high spatial resolution and an ability to acquire repeated recordings over time in order to track pharmacological interventions. Preclinical techniques for studying diseases of neuromuscular transmission can be enhanced by physiologic ex vivo models of tissue-tissue and cell-cell interactions. We present a method, which we used to follow the development of primary skeletal muscle cells from myoblasts into mature contracting myofibers over more than two months. In contrast to most previous studies, the muscles do not detach from the surface but instead form functional networks between the myofibers, whose electrical signals we observed over the entire culturing period. Primary cultures of mouse myoblasts differentiated into contracting myofibers on a chip that contains an array of 26,400 platinum electrodes at a density of 3,265 electrodes per mm2. Our ability to track extracellular action potentials at subcellular resolution enables discovery of the origin of possible failure mechanisms in muscle diseases. This system in turn enables creation of a novel electrophysiological platform for establishing ex vivo disease models.}, keywords = {ETH-CMOS-MEA, Physiology}, pubstate = {published}, tppubtype = {conference} } Close Skeletal (voluntary) muscle is the most abundant tissue in the body, thus making it an important biomedical research subject. Studies of neuromuscular transmission, including disorders of defective ion channels or receptors in autoimmune or genetic neuromuscular disorders, require high spatial resolution and an ability to acquire repeated recordings over time in order to track pharmacological interventions. Preclinical techniques for studying diseases of neuromuscular transmission can be enhanced by physiologic ex vivo models of tissue-tissue and cell-cell interactions. We present a method, which we used to follow the development of primary skeletal muscle cells from myoblasts into mature contracting myofibers over more than two months. In contrast to most previous studies, the muscles do not detach from the surface but instead form functional networks between the myofibers, whose electrical signals we observed over the entire culturing period. Primary cultures of mouse myoblasts differentiated into contracting myofibers on a chip that contains an array of 26,400 platinum electrodes at a density of 3,265 electrodes per mm2. Our ability to track extracellular action potentials at subcellular resolution enables discovery of the origin of possible failure mechanisms in muscle diseases. This system in turn enables creation of a novel electrophysiological platform for establishing ex vivo disease models. Close https://abstractsonline.com/pp8/#!/4649/presentation/24936 Close
	Fiscella, Michele; Leary, Noelle; Ronchi, Silvia; Hierlemann, Andreas Electrophysiological phenotype characterization of human iPSC-derived dopaminergic neuronal lines by means of high-resolution microelectrode array Conference Contribution 700.13 , Society for Neuroscience (SfN) Meeting San Diego, CA, USA, 2018. Abstract \| Links \| BibTeX \| タグ: HD-MEA, IPSC @conference{Fiscella2018, title = {Electrophysiological phenotype characterization of human iPSC-derived dopaminergic neuronal lines by means of high-resolution microelectrode array}, author = {Michele Fiscella and Noelle Leary and Silvia Ronchi and Andreas Hierlemann }, url = {https://www.abstractsonline.com/pp8/#!/4649/presentation/24924}, year = {2018}, date = {2018-11-07}, volume = {Contribution 700.13}, address = {San Diego, CA, USA}, organization = {Society for Neuroscience (SfN) Meeting}, abstract = {High-resolution-microelectrode-array (HD-MEA) technology enables to study neuronal dynamics at different scales, ranging from axonal physiology to network connectivity [1]. We have used this HD-MEA technology to characterize and compare the electrical phenotypes of commercially available human dopaminergic neurons (iCell DopaNeurons, MyCell DopaNeurons A53T α-synuclein, Cellular Dynamics International, Madison, WI, US). Furthermore, we have studied the effect of human astrocytes (iCell Astrocytes, Cellular Dynamics International, Madison, WI, US) on neural-culture development. Astrocyte/neuron co-cultures showed higher signal amplitudes and higher firing rates than neural cultures without astrocytes. Adding astrocytes to neural cultures changed the whole culture morphology by promoting cell clustering. Interestingly, astrocyte/neuron co-cultures showed a lower sample-to-sample variability across multiple HD-MEA recordings compared to neural cultures without astrocytes. We compared action potential propagation velocities along axons between dopaminergic A53T α-synuclein neurons and the wild-type isogenic control cell line. We found that in both, wild-type and disease-model neurons, axonal action potential propagation velocities were lower than in rat primary cortical neurons [2]. Furthermore, we found different axonal-action-potential-velocity-development profiles of A53T α-synuclein dopaminergic neurons and the wild-type counterpart. Finally, we were able to precisely evoke action potentials in individual single human neurons by subcellular-resolution electrical stimulation. HD-MEA systems enable to access novel electrophysiological parameters of iPSC-derived neurons, which can be potentially used as biomarkers for phenotype screening and drug testing.}, keywords = {HD-MEA, IPSC}, pubstate = {published}, tppubtype = {conference} } Close High-resolution-microelectrode-array (HD-MEA) technology enables to study neuronal dynamics at different scales, ranging from axonal physiology to network connectivity [1]. We have used this HD-MEA technology to characterize and compare the electrical phenotypes of commercially available human dopaminergic neurons (iCell DopaNeurons, MyCell DopaNeurons A53T α-synuclein, Cellular Dynamics International, Madison, WI, US). Furthermore, we have studied the effect of human astrocytes (iCell Astrocytes, Cellular Dynamics International, Madison, WI, US) on neural-culture development. Astrocyte/neuron co-cultures showed higher signal amplitudes and higher firing rates than neural cultures without astrocytes. Adding astrocytes to neural cultures changed the whole culture morphology by promoting cell clustering. Interestingly, astrocyte/neuron co-cultures showed a lower sample-to-sample variability across multiple HD-MEA recordings compared to neural cultures without astrocytes. We compared action potential propagation velocities along axons between dopaminergic A53T α-synuclein neurons and the wild-type isogenic control cell line. We found that in both, wild-type and disease-model neurons, axonal action potential propagation velocities were lower than in rat primary cortical neurons [2]. Furthermore, we found different axonal-action-potential-velocity-development profiles of A53T α-synuclein dopaminergic neurons and the wild-type counterpart. Finally, we were able to precisely evoke action potentials in individual single human neurons by subcellular-resolution electrical stimulation. HD-MEA systems enable to access novel electrophysiological parameters of iPSC-derived neurons, which can be potentially used as biomarkers for phenotype screening and drug testing. Close https://www.abstractsonline.com/pp8/#!/4649/presentation/24924 Close
	Emmenegger, Vishalini; Bartram, Julian; Sitnikov, Sergey; Hierlemann, Andreas Investigating the analog modulation of action-potential waveforms in axonal arbors of cortical neurons using whole-cell patch-clamp recordings and high-density microelectrode arrays Conference Contribution 203.05 , Society for Neuroscience (SfN) Meeting, San Diego, CA, USA, 2018. Abstract \| Links \| BibTeX \| タグ: ETH-CMOS-MEA @conference{Emmenegger2018, title = {Investigating the analog modulation of action-potential waveforms in axonal arbors of cortical neurons using whole-cell patch-clamp recordings and high-density microelectrode arrays}, author = {Vishalini Emmenegger and Julian Bartram and Sergey Sitnikov and Andreas Hierlemann}, url = {https://abstractsonline.com/pp8/#!/4649/presentation/9323}, year = {2018}, date = {2018-11-04}, volume = {Contribution 203.05}, publisher = {Society for Neuroscience (SfN) Meeting}, address = {San Diego, CA, USA}, abstract = {Analog-digital facilitation (ADF) is a type of short-term plasticity, where the subthreshold membrane potential in the presynaptic element enhances the spike-evoked synaptic response. Most cases of ADF have been induced by long (0.3-10 s) subthreshold depolarization of the soma, while in few cases, transient (15-200 ms) hyperpolarization has been evoked immediately before the action potential (AP). In both cases, somatic membrane fluctuations modulate the biophysical properties of voltage-gated ion channels causing changes in the AP waveform, which result in larger release of neurotransmitters. However, it is still unknown, whether the modulation of the AP waveform changes with increasing distance from the soma and differs in different axonal arbors, and whether such modulation affects the velocity of AP propagation. Here, we used CMOS-based high-density microelectrode arrays (HD-MEA) with 26,400 microelectrodes, which enabled unprecedented high-resolution access to investigating axonal signaling at multiple sites simultaneously, thus providing in-depth information on the propagation of AP. The subthreshold depolarization and hyperpolarization of the presynaptic cell was performed using whole-cell patch-clamp recordings from cells in low-density cortical cultures, plated on a HD-MEA that allowed to trace the effects of such manipulations on AP propagation characteristics. Array-wide spike-triggered average signals were computed, and their spatiotemporal distribution was reconstructed. In order to study the changes in extracellular AP waveforms, we first induced pharmacological modulations using dendrotoxin and carbamazepine, which increased AP width and amplitude. As a next step, we evoked AP broadening and amplitude changes by subthreshold depolarization and hyperpolarization. We detected the extracellular AP waveforms directly under the soma and traced them throughout the axon during various time spans and for different holding potentials. We found that changes in AP propagation velocity were correlated to the detected AP broadening. Our preliminary data evidenced changes in AP waveforms with increasing distance from the soma along the axon, but further experiments on synaptically coupled neurons using paired recordings will be performed to better understand the influence of AP modulation on ADF. Information encoding in neuronal circuits is probably contingent on both, temporal spike patterns and spike waveforms. In the light of the latter being typically disregarded in computational models, the study of the analog modulation of AP waveforms will contribute to a better understanding of neuronal information processing.}, keywords = {ETH-CMOS-MEA}, pubstate = {published}, tppubtype = {conference} } Close Analog-digital facilitation (ADF) is a type of short-term plasticity, where the subthreshold membrane potential in the presynaptic element enhances the spike-evoked synaptic response. Most cases of ADF have been induced by long (0.3-10 s) subthreshold depolarization of the soma, while in few cases, transient (15-200 ms) hyperpolarization has been evoked immediately before the action potential (AP). In both cases, somatic membrane fluctuations modulate the biophysical properties of voltage-gated ion channels causing changes in the AP waveform, which result in larger release of neurotransmitters. However, it is still unknown, whether the modulation of the AP waveform changes with increasing distance from the soma and differs in different axonal arbors, and whether such modulation affects the velocity of AP propagation. Here, we used CMOS-based high-density microelectrode arrays (HD-MEA) with 26,400 microelectrodes, which enabled unprecedented high-resolution access to investigating axonal signaling at multiple sites simultaneously, thus providing in-depth information on the propagation of AP. The subthreshold depolarization and hyperpolarization of the presynaptic cell was performed using whole-cell patch-clamp recordings from cells in low-density cortical cultures, plated on a HD-MEA that allowed to trace the effects of such manipulations on AP propagation characteristics. Array-wide spike-triggered average signals were computed, and their spatiotemporal distribution was reconstructed. In order to study the changes in extracellular AP waveforms, we first induced pharmacological modulations using dendrotoxin and carbamazepine, which increased AP width and amplitude. As a next step, we evoked AP broadening and amplitude changes by subthreshold depolarization and hyperpolarization. We detected the extracellular AP waveforms directly under the soma and traced them throughout the axon during various time spans and for different holding potentials. We found that changes in AP propagation velocity were correlated to the detected AP broadening. Our preliminary data evidenced changes in AP waveforms with increasing distance from the soma along the axon, but further experiments on synaptically coupled neurons using paired recordings will be performed to better understand the influence of AP modulation on ADF. Information encoding in neuronal circuits is probably contingent on both, temporal spike patterns and spike waveforms. In the light of the latter being typically disregarded in computational models, the study of the analog modulation of AP waveforms will contribute to a better understanding of neuronal information processing. Close https://abstractsonline.com/pp8/#!/4649/presentation/9323 Close
	Ronchi, Silvia; Fiscella, Michele; Marchetti, Camilla; Viswam, Vijay; Müller, Jan; Frey, Urs; Hierlemann, Andreas Single-neuron sub-cellular-resolution electrical stimulation with high-density microelectrode arrays Conference Contribution 174.05 , Society for Neuroscience (SfN) Meeting San Diego, CA, USA, 2018. Abstract \| Links \| BibTeX \| タグ: ETH-CMOS-MEA, Stimulation @conference{Ronchi2018, title = {Single-neuron sub-cellular-resolution electrical stimulation with high-density microelectrode arrays}, author = {Silvia Ronchi and Michele Fiscella and Camilla Marchetti and Vijay Viswam and Jan Müller and Urs Frey and Andreas Hierlemann}, url = {https://abstractsonline.com/pp8/#!/4649/presentation/24382}, year = {2018}, date = {2018-11-04}, volume = {Contribution 174.05}, address = {San Diego, CA, USA}, organization = {Society for Neuroscience (SfN) Meeting}, abstract = {Non-invasive electrical stimulation is a consolidated technique to study and control neural activity in the brain and peripheral nervous system. It is used, e.g., for controlling Parkinson's disease or to induce sensation in paralyzed patients (Armenta Salas et al., 2018), as well as for attempts to restore vision (Fan et al., 2018; Grosberg et al., 2017) and hearing (Wilson & Dorman, 2008). A common requirement in electrical stimulation is the precise and controlled stimulation of individual targeted neurons. For achieving this purpose, it is necessary that electrodes can stimulate and record extracellular signals at sub-cellular resolution. Furthermore, it is important to design efficient stimulation pulses to be delivered to the neurons. In the present work we used an CMOS-based high-density microelectrode array (HD-MEA) (Ballini et al., 2014), featuring 26’400 bidirectional electrodes with a pitch of 17.5 µm, which was designed for in-vitro applications. This high-resolution was used to test electrical stimulation parameters in vitro, which then could potentially be adapted to elicit single-cell action potentials in vivo. In this work we used different stimulation parameters, such as waveforms, amplitudes and durations (Grosberg et al., 2017; Wagenaar, Pine, & Potter, 2004), using 5x9 µm² electrodes to target sub-cellular structures in single neurons. E-18 Wistar rat cortical neurons were stimulated at days-in-vitro 10, 15, 20 and 25 using randomized voltage and current stimulation modalities. Axon initial segments of individual neurons (Radivojevic et al., 2016) were targeted for stimulation, enabled by the HD-MEA device. We found that voltage biphasic anodic-cathodic waveforms were less efficient than biphasic cathodic-anodic waveforms in eliciting action potentials in a single neuron. Moreover, it was possible to detect action potentials directly at the cell soma, which ensured a reliable confirmation of successful neuron stimulation. Finally, HD-MEA technology enabled to elicit action potentials in single-neurons embedded in high-density cell cultures. The obtained results can be used to optimize in vivo single-cell targeting for stimulation and read-out.}, keywords = {ETH-CMOS-MEA, Stimulation}, pubstate = {published}, tppubtype = {conference} } Close Non-invasive electrical stimulation is a consolidated technique to study and control neural activity in the brain and peripheral nervous system. It is used, e.g., for controlling Parkinson's disease or to induce sensation in paralyzed patients (Armenta Salas et al., 2018), as well as for attempts to restore vision (Fan et al., 2018; Grosberg et al., 2017) and hearing (Wilson & Dorman, 2008). A common requirement in electrical stimulation is the precise and controlled stimulation of individual targeted neurons. For achieving this purpose, it is necessary that electrodes can stimulate and record extracellular signals at sub-cellular resolution. Furthermore, it is important to design efficient stimulation pulses to be delivered to the neurons. In the present work we used an CMOS-based high-density microelectrode array (HD-MEA) (Ballini et al., 2014), featuring 26’400 bidirectional electrodes with a pitch of 17.5 µm, which was designed for in-vitro applications. This high-resolution was used to test electrical stimulation parameters in vitro, which then could potentially be adapted to elicit single-cell action potentials in vivo. In this work we used different stimulation parameters, such as waveforms, amplitudes and durations (Grosberg et al., 2017; Wagenaar, Pine, & Potter, 2004), using 5x9 µm² electrodes to target sub-cellular structures in single neurons. E-18 Wistar rat cortical neurons were stimulated at days-in-vitro 10, 15, 20 and 25 using randomized voltage and current stimulation modalities. Axon initial segments of individual neurons (Radivojevic et al., 2016) were targeted for stimulation, enabled by the HD-MEA device. We found that voltage biphasic anodic-cathodic waveforms were less efficient than biphasic cathodic-anodic waveforms in eliciting action potentials in a single neuron. Moreover, it was possible to detect action potentials directly at the cell soma, which ensured a reliable confirmation of successful neuron stimulation. Finally, HD-MEA technology enabled to elicit action potentials in single-neurons embedded in high-density cell cultures. The obtained results can be used to optimize in vivo single-cell targeting for stimulation and read-out. Close https://abstractsonline.com/pp8/#!/4649/presentation/24382 Close
	Bartram, Julian; Schroter, Manuel; Ronchi, Silvia; Emmenegger, Vishalini; Muller, Jan; Hierlemann, Andreas Mechanisms of homeostatic synaptic plasticity Conference Contribution 037.11 , Society for Neuroscience (SfN) Meeting San Diego, CA, USA, 2018. Abstract \| Links \| BibTeX \| タグ: HD-MEA @conference{Bartram2018, title = {Mechanisms of homeostatic synaptic plasticity}, author = {Julian Bartram and Manuel Schroter and Silvia Ronchi and Vishalini Emmenegger and Jan Muller and Andreas Hierlemann}, url = {https://www.abstractsonline.com/pp8/#!/4649/presentation/3968}, year = {2018}, date = {2018-11-03}, volume = {Contribution 037.11}, address = {San Diego, CA, USA}, organization = {Society for Neuroscience (SfN) Meeting}, abstract = {Homeostatic plasticity is a crucial set of mechanisms acting at typically slow temporal scales in order to stabilize neuronal spike rates. Despite the functional significance of such processes, revealing the precise induction mechanisms has proven to be difficult, as the roles of postsynaptic spiking and synaptic activity are still debated. For a clearer picture of the induction process to emerge, information about synaptic efficacies of multiple inputs needs to be combined with accurate information about spiking activities of the respective presynaptic cells and the postsynaptic cell during the induction of homeostatic plasticity. In this study, we were able to achieve such measurements by performing combined high-density microelectrode array (HD-MEA) and whole-cell patch-clamp recordings in cultures of primary cortical neurons. Homeostatic plasticity was induced by pharmacological alteration of global network spiking and synaptic transmission with TTX or CNQX. Monosynaptic connections between neurons - here with a focus on excitatory connections between pyramidal cells - were identified by correlating presynaptic spiking activity (HD-MEA recordings) with postsynaptic subthreshold responses (patch current-clamp recordings). Presynaptic spiking was spontaneously observed or could be induced via the stimulation capabilities of the HD-MEA system. This experimental approach enabled us to link changes in synaptic efficacy with the respective pre- and postsynaptic spike patterns, recorded during the induction phase, which sheds new light on the rules and mechanisms of homeostatic synaptic plasticity at excitatory synapses. Financial support through the ERC Advanced Grant 694829 “neuroXscales” is gratefully acknowledged.}, keywords = {HD-MEA}, pubstate = {published}, tppubtype = {conference} } Close Homeostatic plasticity is a crucial set of mechanisms acting at typically slow temporal scales in order to stabilize neuronal spike rates. Despite the functional significance of such processes, revealing the precise induction mechanisms has proven to be difficult, as the roles of postsynaptic spiking and synaptic activity are still debated. For a clearer picture of the induction process to emerge, information about synaptic efficacies of multiple inputs needs to be combined with accurate information about spiking activities of the respective presynaptic cells and the postsynaptic cell during the induction of homeostatic plasticity. In this study, we were able to achieve such measurements by performing combined high-density microelectrode array (HD-MEA) and whole-cell patch-clamp recordings in cultures of primary cortical neurons. Homeostatic plasticity was induced by pharmacological alteration of global network spiking and synaptic transmission with TTX or CNQX. Monosynaptic connections between neurons - here with a focus on excitatory connections between pyramidal cells - were identified by correlating presynaptic spiking activity (HD-MEA recordings) with postsynaptic subthreshold responses (patch current-clamp recordings). Presynaptic spiking was spontaneously observed or could be induced via the stimulation capabilities of the HD-MEA system. This experimental approach enabled us to link changes in synaptic efficacy with the respective pre- and postsynaptic spike patterns, recorded during the induction phase, which sheds new light on the rules and mechanisms of homeostatic synaptic plasticity at excitatory synapses. Financial support through the ERC Advanced Grant 694829 “neuroXscales” is gratefully acknowledged. Close https://www.abstractsonline.com/pp8/#!/4649/presentation/3968 Close
	Yuan, Xinyue; Emmenegger, Vishalini; Obien, Marie Engelene J; Hierlemann, Andreas; Frey, Urs Dual-Mode Microelectrode Array Featuring 20k Electrodes and High SNR for Extracellular Recording of Neural Networks Conference paper 6065 , IEEE Biomedical Circuits and Systems Conference (BioCAS) Cleveland, Ohio, USA, 2018. Abstract \| Links \| BibTeX \| タグ: ETH-CMOS-MEA @conference{Yuan2018b, title = {Dual-Mode Microelectrode Array Featuring 20k Electrodes and High SNR for Extracellular Recording of Neural Networks}, author = {Xinyue Yuan and Vishalini Emmenegger and Marie Engelene J. Obien and Andreas Hierlemann and Urs Frey}, url = {https://www.epapers.org/biocas2018/ESR/paper_details.php?PHPSESSID=ok076vdjtkiu7kett65d8hk0g0&paper_id=6056}, year = {2018}, date = {2018-10-17}, volume = {paper 6065}, address = {Cleveland, Ohio, USA}, organization = {IEEE Biomedical Circuits and Systems Conference (BioCAS)}, abstract = {In recent electrophysiological studies, CMOS-based high-density microelectrode arrays (HD-MEA) have been widely used for studies of both in-vitro and in-vivo neuronal signals and network behavior. Yet, an open issue in MEA design concerns the tradeoff between signal-to-noise ratio (SNR) and number of readout channels. Here we present a new HD-MEA design in 0.18 μm CMOS technology, consisting of 19,584 electrodes at a pitch of 18.0 μm. By combing two readout structures,namely active-pixel-sensor (APS) and switch-matrix (SM) on a single chip, the dual-mode HD-MEA is capable of recording simultaneously from the entire array and achieving high signal-to-noise-ratio recordings on a subset of electrodes. The APS readout circuits feature a noise level of 10.9 μVrms for the action potential band (300 Hz - 5 kHz), while the noise level for the switch-matrix readout is 3.1 μVrms. }, keywords = {ETH-CMOS-MEA}, pubstate = {published}, tppubtype = {conference} } Close In recent electrophysiological studies, CMOS-based high-density microelectrode arrays (HD-MEA) have been widely used for studies of both in-vitro and in-vivo neuronal signals and network behavior. Yet, an open issue in MEA design concerns the tradeoff between signal-to-noise ratio (SNR) and number of readout channels. Here we present a new HD-MEA design in 0.18 μm CMOS technology, consisting of 19,584 electrodes at a pitch of 18.0 μm. By combing two readout structures,namely active-pixel-sensor (APS) and switch-matrix (SM) on a single chip, the dual-mode HD-MEA is capable of recording simultaneously from the entire array and achieving high signal-to-noise-ratio recordings on a subset of electrodes. The APS readout circuits feature a noise level of 10.9 μVrms for the action potential band (300 Hz - 5 kHz), while the noise level for the switch-matrix readout is 3.1 μVrms. Close https://www.epapers.org/biocas2018/ESR/paper_details.php?PHPSESSID=ok076vdjtkiu7[...] Close
	Lewandowska, Marta K; Bogatikov, Evgenii; Hierlemann, Andreas; Punga, Anna Rostedt Long-Term High-Density Extracellular Recordings Enable Studies of Muscle Cell Physiology Journal Article Frontiers in Physiology, 9 , 2018. Abstract \| Links \| BibTeX \| タグ: ETH-CMOS-MEA, Muscle @article{Lewandowska2018cb, title = {Long-Term High-Density Extracellular Recordings Enable Studies of Muscle Cell Physiology }, author = {Marta K. Lewandowska and Evgenii Bogatikov and Andreas Hierlemann and Anna Rostedt Punga}, url = {https://www.frontiersin.org/article/10.3389/fphys.2018.01424 }, doi = {10.3389/fphys.2018.01424}, year = {2018}, date = {2018-10-09}, journal = {Frontiers in Physiology}, volume = {9}, abstract = {Skeletal (voluntary) muscle is the most abundant tissue in the body, thus making it an important biomedical research subject. Studies of neuromuscular transmission, including disorders of ion channels or receptors in autoimmune or genetic neuromuscular disorders, require high-spatial-resolution measurement techniques and an ability to acquire repeated recordings over time in order to track pharmacological interventions. Preclinical techniques for studying diseases of neuromuscular transmission can be enhanced by physiologic ex vivo models of tissue-tissue and cell-cell interactions. Here, we present a method, which allows tracking the development of primary skeletal muscle cells from myoblasts into mature contracting myotubes over more than 2 months. In contrast to most previous studies, the myotubes did not detach from the surface but instead formed functional networks between the myotubes, whose electrical signals were observed over the entire culturing period. Primary cultures of mouse myoblasts differentiated into contracting myotubes on a chip that contained an array of 26,400 platinum electrodes at a density of 3,265 electrodes per mm2. Our ability to track extracellular action potentials at subcellular resolution enabled study of skeletal muscle development and kinetics, modes of spiking and spatio-temporal relationships between muscles. The developed system in turn enables creation of a novel electrophysiological platform for establishing ex vivo disease models. }, keywords = {ETH-CMOS-MEA, Muscle}, pubstate = {published}, tppubtype = {article} } Close Skeletal (voluntary) muscle is the most abundant tissue in the body, thus making it an important biomedical research subject. Studies of neuromuscular transmission, including disorders of ion channels or receptors in autoimmune or genetic neuromuscular disorders, require high-spatial-resolution measurement techniques and an ability to acquire repeated recordings over time in order to track pharmacological interventions. Preclinical techniques for studying diseases of neuromuscular transmission can be enhanced by physiologic ex vivo models of tissue-tissue and cell-cell interactions. Here, we present a method, which allows tracking the development of primary skeletal muscle cells from myoblasts into mature contracting myotubes over more than 2 months. In contrast to most previous studies, the myotubes did not detach from the surface but instead formed functional networks between the myotubes, whose electrical signals were observed over the entire culturing period. Primary cultures of mouse myoblasts differentiated into contracting myotubes on a chip that contained an array of 26,400 platinum electrodes at a density of 3,265 electrodes per mm2. Our ability to track extracellular action potentials at subcellular resolution enabled study of skeletal muscle development and kinetics, modes of spiking and spatio-temporal relationships between muscles. The developed system in turn enables creation of a novel electrophysiological platform for establishing ex vivo disease models. Close https://www.frontiersin.org/article/10.3389/fphys.2018.01424 doi:10.3389/fphys.2018.01424 Close
	Diggelmann, Roland; Fiscella, Michele; Hierlemann, Andreas; Franke, Felix Automatic Spike Sorting Algorithm for High-Density Microelectrode Arrays Journal Article Journal of Neurophysiology, 120 (4), 2018. Abstract \| Links \| BibTeX \| タグ: MEA Technology @article{Diggelmann2018, title = {Automatic Spike Sorting Algorithm for High-Density Microelectrode Arrays}, author = {Roland Diggelmann and Michele Fiscella and Andreas Hierlemann and Felix Franke}, url = {https://www.physiology.org/doi/pdf/10.1152/jn.00803.2017}, doi = {10.1152/jn.00803.2017}, year = {2018}, date = {2018-09-12}, journal = {Journal of Neurophysiology}, volume = {120}, number = {4}, abstract = {High-density microelectrode arrays (HD-MEAs) can be used to record extracellular action potentials from hundreds to thousands of neurons simultaneously. Efficient spike-sorters have to be developed to cope with such large data volumes. Most existing spike sorting methods for single electrodes or small multi-electrodes, however, suffer from the "curse of dimensionality", and cannot be directly applied to recordings with hundreds of electrodes. This holds particularly true for the standard reference spike sorting algorithm, principal-component-analysis-based feature extraction, followed by k-means or expectation maximization clustering, against which most spike-sorters are evaluated. We present a spike sorting algorithm that circumvents the dimensionality problem by sorting local groups of electrodes independently using classical spike sorting approaches. It is scalable to any number of recording electrodes and well suited for parallel computing. The combination of data pre-whitening before the principal-component-analysis-based extraction and a parameter-free clustering algorithm obviated the need for parameter adjustments. We evaluated its performance using surrogate data in which we systematically varied spike amplitudes and spike rates and which were generated by inserting template spikes into the voltage traces of real recordings. In a direct comparison, our algorithm could compete with existing state-of-the-art spike sorters in terms of sensitivity and precision, while parameter adjustment or manual cluster curation were not required.}, keywords = {MEA Technology}, pubstate = {published}, tppubtype = {article} } Close High-density microelectrode arrays (HD-MEAs) can be used to record extracellular action potentials from hundreds to thousands of neurons simultaneously. Efficient spike-sorters have to be developed to cope with such large data volumes. Most existing spike sorting methods for single electrodes or small multi-electrodes, however, suffer from the "curse of dimensionality", and cannot be directly applied to recordings with hundreds of electrodes. This holds particularly true for the standard reference spike sorting algorithm, principal-component-analysis-based feature extraction, followed by k-means or expectation maximization clustering, against which most spike-sorters are evaluated. We present a spike sorting algorithm that circumvents the dimensionality problem by sorting local groups of electrodes independently using classical spike sorting approaches. It is scalable to any number of recording electrodes and well suited for parallel computing. The combination of data pre-whitening before the principal-component-analysis-based extraction and a parameter-free clustering algorithm obviated the need for parameter adjustments. We evaluated its performance using surrogate data in which we systematically varied spike amplitudes and spike rates and which were generated by inserting template spikes into the voltage traces of real recordings. In a direct comparison, our algorithm could compete with existing state-of-the-art spike sorters in terms of sensitivity and precision, while parameter adjustment or manual cluster curation were not required. Close https://www.physiology.org/doi/pdf/10.1152/jn.00803.2017 doi:10.1152/jn.00803.2017 Close
	Ronchi, Silvia; Fiscella, Michele; Muller, Jan; Viswam, Vijay; Frey, Urs; Hierlemann, Andreas Single-cell electrical stimulation with CMOS-based high-density microelectrode arrays Conference 11th International Meeting on Substrate Integrated Microelectrode Arrays (MEA Meeting) Reutlingen, Germany, 2018. Abstract \| Links \| BibTeX \| タグ: ETH-CMOS-MEA, Stimulation @conference{Ronchi2018b, title = {Single-cell electrical stimulation with CMOS-based high-density microelectrode arrays}, author = {Silvia Ronchi and Michele Fiscella and Jan Muller and Vijay Viswam and Urs Frey and Andreas Hierlemann}, url = {https://www.frontiersin.org/10.3389/conf.fncel.2018.38.00086/event_abstract}, doi = {10.3389/conf.fncel.2018.38.00086}, year = {2018}, date = {2018-07-04}, address = {Reutlingen, Germany}, organization = {11th International Meeting on Substrate Integrated Microelectrode Arrays (MEA Meeting)}, abstract = {The main goal of this work was to explore electrical stimulation parameters that reproducibly and precisely elicit action potentials in single neurons (Wagenaar et al. 2004). We compared voltage and current modalities’ and their efficacy in activating single neurons; we also studied the related stimulation artifacts. For our studies, we used a CMOS-based MEA featuring 26400 electrodes at 17.5 µm pitch (Ballini et al. 2014). }, keywords = {ETH-CMOS-MEA, Stimulation}, pubstate = {published}, tppubtype = {conference} } Close The main goal of this work was to explore electrical stimulation parameters that reproducibly and precisely elicit action potentials in single neurons (Wagenaar et al. 2004). We compared voltage and current modalities’ and their efficacy in activating single neurons; we also studied the related stimulation artifacts. For our studies, we used a CMOS-based MEA featuring 26400 electrodes at 17.5 µm pitch (Ballini et al. 2014). Close https://www.frontiersin.org/10.3389/conf.fncel.2018.38.00086/event_abstract doi:10.3389/conf.fncel.2018.38.00086 Close
	Obien, Marie Engelene J; Zorzi, Giulio; Fiscella, Michele; Leary, Noelle; Hierlemann, Andreas Comparison of axonal-conduction velocity in developing primary cells and human iPSC-derived neurons Conference 11th International Meeting on Substrate Integrated Microelectrode Arrays (MEA Meeting) Reutlingen, Germany, 2018. Abstract \| Links \| BibTeX \| タグ: ETH-CMOS-MEA, MaxOne @conference{Obien2018, title = {Comparison of axonal-conduction velocity in developing primary cells and human iPSC-derived neurons}, author = {Marie Engelene J. Obien and Giulio Zorzi and Michele Fiscella and Noelle Leary and Andreas Hierlemann}, url = {https://www.frontiersin.org/10.3389/conf.fncel.2018.38.00095/event_abstract}, doi = {10.3389/conf.fncel.2018.38.00095}, year = {2018}, date = {2018-07-04}, address = {Reutlingen, Germany}, organization = {11th International Meeting on Substrate Integrated Microelectrode Arrays (MEA Meeting)}, abstract = {Neurons communicate through action potentials propagating along axons. In developing cell cultures, axonal arbor outgrowth indicates the formation of synaptic connections between neurons, which form networks. As axons regulate the transfer of information, we hypothesize that axonal conduction characteristics, e.g., axonal action potential amplitude and propagation velocity, may be indicative of the maturation state of cells and the strength of interneuronal connections.}, keywords = {ETH-CMOS-MEA, MaxOne}, pubstate = {published}, tppubtype = {conference} } Close Neurons communicate through action potentials propagating along axons. In developing cell cultures, axonal arbor outgrowth indicates the formation of synaptic connections between neurons, which form networks. As axons regulate the transfer of information, we hypothesize that axonal conduction characteristics, e.g., axonal action potential amplitude and propagation velocity, may be indicative of the maturation state of cells and the strength of interneuronal connections. Close https://www.frontiersin.org/10.3389/conf.fncel.2018.38.00095/event_abstract doi:10.3389/conf.fncel.2018.38.00095 Close
	Zorzi, Giulio; Obien, Marie Engelene J; Fiscella, Michele; Leary, Noelle; Hierlemann, Andreas Automatic extraction of axonal arbor morphology applied to h-iPSC-derived neurons Conference 11th International Meeting on Substrate Integrated Microelectrode Arrays (MEA Meeting) Reutlingen, Germany, 2018. Abstract \| Links \| BibTeX \| タグ: ETH-CMOS-MEA, MaxOne @conference{Zorzi2018, title = {Automatic extraction of axonal arbor morphology applied to h-iPSC-derived neurons}, author = {Giulio Zorzi and Marie Engelene J. Obien and Michele Fiscella and Noelle Leary and Andreas Hierlemann}, url = {https://www.frontiersin.org/10.3389/conf.fncel.2018.38.00049/event_abstract}, doi = {10.3389/conf.fncel.2018.38.00049}, year = {2018}, date = {2018-07-04}, address = {Reutlingen, Germany}, organization = {11th International Meeting on Substrate Integrated Microelectrode Arrays (MEA Meeting)}, abstract = {Neurons derived from human induced pluripotent stem cells (h-iPSCs) offer tremendous opportunities to investigate the mechanisms involved in brain function and to model neurodegenerative diseases. Analyzing the behavior of h-iPSC-derived neurons that represent the phenotypes of human neurological disorders paves the way for the development of physiologically-relevant models and assays for drug discovery. In this framework, we utilize a CMOS-based high-density microelectrode array (HD-MEA, MaxWell Biosystems) to investigate h-iPSC neurons at sub-cellular resolution. Recording extracellular action potentials (EAPs or spikes) of cultured neurons through microelectrode arrays (MEAs) is a well-established technique for extracting valuable features of neuronal function and network connectivity (Obien et al., Frontiers in Neuroscience, 2015). }, keywords = {ETH-CMOS-MEA, MaxOne}, pubstate = {published}, tppubtype = {conference} } Close Neurons derived from human induced pluripotent stem cells (h-iPSCs) offer tremendous opportunities to investigate the mechanisms involved in brain function and to model neurodegenerative diseases. Analyzing the behavior of h-iPSC-derived neurons that represent the phenotypes of human neurological disorders paves the way for the development of physiologically-relevant models and assays for drug discovery. In this framework, we utilize a CMOS-based high-density microelectrode array (HD-MEA, MaxWell Biosystems) to investigate h-iPSC neurons at sub-cellular resolution. Recording extracellular action potentials (EAPs or spikes) of cultured neurons through microelectrode arrays (MEAs) is a well-established technique for extracting valuable features of neuronal function and network connectivity (Obien et al., Frontiers in Neuroscience, 2015). Close https://www.frontiersin.org/10.3389/conf.fncel.2018.38.00049/event_abstract doi:10.3389/conf.fncel.2018.38.00049 Close
	Bounik, Raziyeh; Gusmaroli, Massimiliano; Viswam, Vijay; Modena, Mario M; Hierlemann, Andreas COMSOL modeling of an integrated impedance sensor in a hanging-drop platform Conference 11th International Meeting on Substrate Integrated Microelectrode Arrays (MEA Meeting) Reutlingen, Germany, 2018. Abstract \| Links \| BibTeX \| タグ: ETH-CMOS-MEA, Microtissue @conference{Bounik2018, title = {COMSOL modeling of an integrated impedance sensor in a hanging-drop platform}, author = {Raziyeh Bounik and Massimiliano Gusmaroli and Vijay Viswam and Mario M. Modena and Andreas Hierlemann}, url = {https://www.frontiersin.org/10.3389/conf.fncel.2018.38.00083/event_abstract}, doi = {10.3389/conf.fncel.2018.38.00083}, year = {2018}, date = {2018-07-04}, address = {Reutlingen, Germany}, organization = {11th International Meeting on Substrate Integrated Microelectrode Arrays (MEA Meeting)}, abstract = {Traditional dish-based, two-dimensional cell cultures have limited prediction capability for drug testing, whereas three-dimensional spherical microtissues (spheroids) and organoids much more accurately replicate physiological conditions of cells in the respective tissue [1,2]. Such spheroids can be formed and cultured in microphysiological multi-tissue formats by using the hanging-drop technology as depicted in Fig. 1 [3]. Like most other microfluidic platforms, the hanging-drop platform still requires a microscope for visual inspection and considerable time for doing off-line measurements, as the spheroids/media have to be harvested from the microfluidic device for labeling and chemical analysis. It would be beneficial to have an integrated on-line multi-functional sensor as an additional readout, located directly at the tissue sites in the hanging-drop platform, so that measurements can be performed in situ and without harvesting medium or the tissue and without interrupting the overall culturing process. }, keywords = {ETH-CMOS-MEA, Microtissue}, pubstate = {published}, tppubtype = {conference} } Close Traditional dish-based, two-dimensional cell cultures have limited prediction capability for drug testing, whereas three-dimensional spherical microtissues (spheroids) and organoids much more accurately replicate physiological conditions of cells in the respective tissue [1,2]. Such spheroids can be formed and cultured in microphysiological multi-tissue formats by using the hanging-drop technology as depicted in Fig. 1 [3]. Like most other microfluidic platforms, the hanging-drop platform still requires a microscope for visual inspection and considerable time for doing off-line measurements, as the spheroids/media have to be harvested from the microfluidic device for labeling and chemical analysis. It would be beneficial to have an integrated on-line multi-functional sensor as an additional readout, located directly at the tissue sites in the hanging-drop platform, so that measurements can be performed in situ and without harvesting medium or the tissue and without interrupting the overall culturing process. Close https://www.frontiersin.org/10.3389/conf.fncel.2018.38.00083/event_abstract doi:10.3389/conf.fncel.2018.38.00083 Close
	Yuan, Xinyue; Hierlemann, Andreas; Frey, Urs Dual-mode Microelectrode Array with 20k-electrodes and High SNR for High-Throughput Extracellular Recording and Stimulation Conference 11th International Meeting on Substrate Integrated Microelectrode Arrays (MEA Meeting) Reutlingen, Germany, 2018. Abstract \| Links \| BibTeX \| タグ: ETH-CMOS-MEA, Stimulation @conference{Yuan2018, title = {Dual-mode Microelectrode Array with 20k-electrodes and High SNR for High-Throughput Extracellular Recording and Stimulation}, author = {Xinyue Yuan and Andreas Hierlemann and Urs Frey}, url = {https://https://www.frontiersin.org/Community/AbstractDetails.aspx?ABS_DOI=10.3389/conf.fncel.2018.38.00088&eid=5473&sname=MEA_Meeting_2018_%7C_11th_International_Meeting_on_Substrate_Integrated_Microelectrode_Arrays}, doi = {10.3389/conf.fncel.2018.38.00088}, year = {2018}, date = {2018-07-04}, address = {Reutlingen, Germany}, organization = {11th International Meeting on Substrate Integrated Microelectrode Arrays (MEA Meeting)}, abstract = {Recording and analysis of neuronal signals can provide much insight into how neurons process information and communicate with each other. Recent advancements of microelectrode-array (MEA) technology provide unprecedented means to study neuronal signals and network behavior in in vitro and in vivo applications [1], [2]. The trade-off between noise performance, power consumption and electrode density, however, remains a major challenge in MEA design. To balance this tradeoff, we designed a Dual-mode (DM) MEA that combines two major types of readout schemes, i.e., the active-pixel-sensor (APS) and switch-matrix (SM) schemes, in order to achieve high electrode density and high signal-to-noise ratio (SNR) at the same time. Based on a previous prototype [3], the new DM-MEA has shown to be a useful tool for in-vitro neuroscience studies, especially for network studies}, keywords = {ETH-CMOS-MEA, Stimulation}, pubstate = {published}, tppubtype = {conference} } Close Recording and analysis of neuronal signals can provide much insight into how neurons process information and communicate with each other. Recent advancements of microelectrode-array (MEA) technology provide unprecedented means to study neuronal signals and network behavior in in vitro and in vivo applications [1], [2]. The trade-off between noise performance, power consumption and electrode density, however, remains a major challenge in MEA design. To balance this tradeoff, we designed a Dual-mode (DM) MEA that combines two major types of readout schemes, i.e., the active-pixel-sensor (APS) and switch-matrix (SM) schemes, in order to achieve high electrode density and high signal-to-noise ratio (SNR) at the same time. Based on a previous prototype [3], the new DM-MEA has shown to be a useful tool for in-vitro neuroscience studies, especially for network studies Close https://https://www.frontiersin.org/Community/AbstractDetails.aspx?ABS_DOI=10.33[...] doi:10.3389/conf.fncel.2018.38.00088 Close
	Fiscella, Michele; Leary, Noelle; Ronchi, Silvia; Hierlemann, Andreas Electrophysiological phenotype characterization of human iPSC-derived dopaminergic neuronal lines by means of high-resolution microelelectrode arrays Conference 11th International Meeting on Substrate Integrated Microelectrode Arrays (MEA Meeting) Reutlingen, Germany, 2018. Abstract \| Links \| BibTeX \| タグ: HD-MEA, IPSC @conference{Fiscella2018c, title = {Electrophysiological phenotype characterization of human iPSC-derived dopaminergic neuronal lines by means of high-resolution microelelectrode arrays}, author = {Michele Fiscella and Noelle Leary and Silvia Ronchi and Andreas Hierlemann}, url = {https://www.frontiersin.org/Community/AbstractDetails.aspx?ABS_DOI=10.3389/conf.fncel.2018.38.00014&eid=5473&sname=MEA_Meeting_2018_%7C_11th_International_Meeting_on_Substrate_Integrated_Microelectrode_Arrays}, doi = {10.3389/conf.fncel.2018.38.00014}, year = {2018}, date = {2018-07-04}, address = {Reutlingen, Germany}, organization = {11th International Meeting on Substrate Integrated Microelectrode Arrays (MEA Meeting)}, abstract = {High-resolution-microelectrode-array (MEA) technology enables to study neuronal dynamics at different scales, ranging from axonal physiology to network connectivity (Müller et. al, Lab on a Chip, 2015). We have used this MEA technology to characterize and compare the electrical phenotypes of commercially available human dopaminergic neurons (iCell DopaNeurons, MyCell DopaNeurons A53T α-synuclein, Cellular Dynamics International, Madison, WI, US). Furthermore, we have studied the effect of human astrocytes (iCell Astrocytes, Cellular Dynamics International, Madison, WI, US) on neural culture development. Astrocyte/neuron co-cultures showed higher signal amplitudes and higher firing rates than neural cultures without astrocytes. Adding astrocytes to neural cultures changed the whole culture morphology by promoting cell clustering. Interestingly, astrocyte/neuron co-cultures showed a lower sample-to-sample variability across multiple MEA recording sessions compared to neural cultures without astrocytes. We compared velocities of action potential propagation along axons between dopaminergic A53T α-synuclein neurons and the wild-type isogenic control cell line. We found that in both, wild-type and disease-model neurons, axonal action potential propagation velocities were lower than, for example, in rat primary cortical neurons (Bakkum et. al, Nature Communications, 2013). Furthermore, we found different axonal action-potential-velocity development profiles of A53T α-synuclein dopaminergic neurons and the wild-typecell line. Finally, we were able to precisely and reproducibly evoke action potentials in individual single human IPSC-derived neurons through subcellular-resolution electrical stimulation. High-resolution MEA systems enable to access novel electrophysiological parameters of iPSC-derived neurons, which can be potentially used as biomarkers for phenotype screening and drug testing.}, keywords = {HD-MEA, IPSC}, pubstate = {published}, tppubtype = {conference} } Close High-resolution-microelectrode-array (MEA) technology enables to study neuronal dynamics at different scales, ranging from axonal physiology to network connectivity (Müller et. al, Lab on a Chip, 2015). We have used this MEA technology to characterize and compare the electrical phenotypes of commercially available human dopaminergic neurons (iCell DopaNeurons, MyCell DopaNeurons A53T α-synuclein, Cellular Dynamics International, Madison, WI, US). Furthermore, we have studied the effect of human astrocytes (iCell Astrocytes, Cellular Dynamics International, Madison, WI, US) on neural culture development. Astrocyte/neuron co-cultures showed higher signal amplitudes and higher firing rates than neural cultures without astrocytes. Adding astrocytes to neural cultures changed the whole culture morphology by promoting cell clustering. Interestingly, astrocyte/neuron co-cultures showed a lower sample-to-sample variability across multiple MEA recording sessions compared to neural cultures without astrocytes. We compared velocities of action potential propagation along axons between dopaminergic A53T α-synuclein neurons and the wild-type isogenic control cell line. We found that in both, wild-type and disease-model neurons, axonal action potential propagation velocities were lower than, for example, in rat primary cortical neurons (Bakkum et. al, Nature Communications, 2013). Furthermore, we found different axonal action-potential-velocity development profiles of A53T α-synuclein dopaminergic neurons and the wild-typecell line. Finally, we were able to precisely and reproducibly evoke action potentials in individual single human IPSC-derived neurons through subcellular-resolution electrical stimulation. High-resolution MEA systems enable to access novel electrophysiological parameters of iPSC-derived neurons, which can be potentially used as biomarkers for phenotype screening and drug testing. Close https://www.frontiersin.org/Community/AbstractDetails.aspx?ABS_DOI=10.3389/conf.[...] doi:10.3389/conf.fncel.2018.38.00014 Close
	Urwyler, Cedar; Bounik, Raziyeh; Viswam, Vijay; Hierlemann, Andreas Electrical impedance tomography on high-density microelectrode arrays Conference 11th International Meeting on Substrate Integrated Microelectrode Arrays (MEA Meeting) Reutlingen, Germany, 2018. Abstract \| Links \| BibTeX \| タグ: HD-MEA @conference{Urwyler2018, title = {Electrical impedance tomography on high-density microelectrode arrays}, author = {Cedar Urwyler and Raziyeh Bounik and Vijay Viswam and Andreas Hierlemann }, url = {https://www.frontiersin.org/10.3389/conf.fncel.2018.38.00084/event_abstract}, doi = {10.3389/conf.fncel.2018.38.00084}, year = {2018}, date = {2018-07-04}, address = {Reutlingen, Germany}, organization = {11th International Meeting on Substrate Integrated Microelectrode Arrays (MEA Meeting)}, abstract = {Electrical impedance tomography (EIT) is a non-invasive, label-free imaging technique that enables to reconstruct the conductivity distribution in a body from a series of impedance measurements. Impedance measurements can be used to determine the position, morphology, and growth of cells or tissues, as well as pathological signs, e.g., precancerous tissue conditions (Gersing 1999). The newest high-density microelectrode array (MEA) system developed in our group features 59,760 integrated electrodes (Dragas et al. 2017). The chip features a variety of electrophysiological functions: Action-potential recording (2048 channels), cyclic voltammetry (28 channels), local-field-potential recording (32 channels) and extracellular stimulation (16 channels) [Fig 1A]. The chip can also measure impedance through 32 channels, which enables EIT measurements. We were able to establish a proof of concept for EIT (Viswam et al. 2017). The current goal of this project is to develop an impedance measurement protocol and an appropriate reconstruction algorithm that allow for single-cell-resolution impedance imaging.}, keywords = {HD-MEA}, pubstate = {published}, tppubtype = {conference} } Close Electrical impedance tomography (EIT) is a non-invasive, label-free imaging technique that enables to reconstruct the conductivity distribution in a body from a series of impedance measurements. Impedance measurements can be used to determine the position, morphology, and growth of cells or tissues, as well as pathological signs, e.g., precancerous tissue conditions (Gersing 1999). The newest high-density microelectrode array (MEA) system developed in our group features 59,760 integrated electrodes (Dragas et al. 2017). The chip features a variety of electrophysiological functions: Action-potential recording (2048 channels), cyclic voltammetry (28 channels), local-field-potential recording (32 channels) and extracellular stimulation (16 channels) [Fig 1A]. The chip can also measure impedance through 32 channels, which enables EIT measurements. We were able to establish a proof of concept for EIT (Viswam et al. 2017). The current goal of this project is to develop an impedance measurement protocol and an appropriate reconstruction algorithm that allow for single-cell-resolution impedance imaging. Close https://www.frontiersin.org/10.3389/conf.fncel.2018.38.00084/event_abstract doi:10.3389/conf.fncel.2018.38.00084 Close
	Schroter, Manuel; Girr, Monika; Boos, Julia Alicia; Renner, Magdalena; Gazorpak, Mahshid; Gong, Wei; Bartram, Julian; Muller, Jan; Hierlemann, Andreas Mapping neuronal network dynamics in developing cerebral organoids Conference 11th International Meeting on Substrate Integrated Microelectrode Arrays (MEA Meeting) Reutlingen, Germany, 2018. Abstract \| Links \| BibTeX \| タグ: Neuronal Networks, Organoids @conference{Schroter2018, title = {Mapping neuronal network dynamics in developing cerebral organoids}, author = {Manuel Schroter and Monika Girr and Julia Alicia Boos and Magdalena Renner and Mahshid Gazorpak and Wei Gong and Julian Bartram and Jan Muller and Andreas Hierlemann}, url = {https://www.frontiersin.org/10.3389/conf.fncel.2018.38.00066/event_abstract}, doi = {10.3389/conf.fncel.2018.38.00066}, year = {2018}, date = {2018-07-04}, address = {Reutlingen, Germany}, organization = {11th International Meeting on Substrate Integrated Microelectrode Arrays (MEA Meeting)}, abstract = {Cerebral organoids represent an attractive, novel model system to study early brain development in vitro (Di Lullo and Kriegstein, 2017). Although recent evidence shows that cerebral organoids do recapitulate fundamental milestones of early brain morphogenesis (Lancaster and Knoblich, 2014), the emergence and functionality of brain-organoid neuronal connectivity has not been studied systematically yet. In this study, we apply high-density micro-electrode arrays (MEAs) to record from developing mouse cerebral organoids and characterize their spontaneous neuronal activity. Results provide first evidence on the potential of MEAs as a platform to study the role of spontaneous neuronal activity during brain organoid development and formation of functional microcircuits. }, keywords = {Neuronal Networks, Organoids}, pubstate = {published}, tppubtype = {conference} } Close Cerebral organoids represent an attractive, novel model system to study early brain development in vitro (Di Lullo and Kriegstein, 2017). Although recent evidence shows that cerebral organoids do recapitulate fundamental milestones of early brain morphogenesis (Lancaster and Knoblich, 2014), the emergence and functionality of brain-organoid neuronal connectivity has not been studied systematically yet. In this study, we apply high-density micro-electrode arrays (MEAs) to record from developing mouse cerebral organoids and characterize their spontaneous neuronal activity. Results provide first evidence on the potential of MEAs as a platform to study the role of spontaneous neuronal activity during brain organoid development and formation of functional microcircuits. Close https://www.frontiersin.org/10.3389/conf.fncel.2018.38.00066/event_abstract doi:10.3389/conf.fncel.2018.38.00066 Close
	Bartram, Julian; Schroter, Manuel; Ronchi, Silvia; Emmenegger, Vishalini; Muller, Jan; Hierlemann, Andreas Probing synaptic connectivity and function using high-density microelectrode arrays and whole-cell patch-clamp recordings Conference 11th International Meeting on Substrate Integrated Microelectrode Arrays (MEA Meeting) Reutlingen, Germany, 2018. Abstract \| Links \| BibTeX \| タグ: HD-MEA @conference{Bartram2018b, title = {Probing synaptic connectivity and function using high-density microelectrode arrays and whole-cell patch-clamp recordings}, author = {Julian Bartram and Manuel Schroter and Silvia Ronchi and Vishalini Emmenegger and Jan Muller and Andreas Hierlemann}, url = {https://www.frontiersin.org/10.3389/conf.fncel.2018.38.00085/5473/MEA_Meeting_2018_%7C_11th_International_Meeting_on_Substrate_Integrated_Microelectrode_Arrays/all_events/event_abstract}, doi = {10.3389/conf.fncel.2018.38.00085}, year = {2018}, date = {2018-07-04}, address = {Reutlingen, Germany}, organization = {11th International Meeting on Substrate Integrated Microelectrode Arrays (MEA Meeting)}, abstract = {Synaptic efficacy and synapse number of monosynaptic connections between neurons are often regulated by the spiking activity of the respective pre- and postsynaptic cell. Progress towards a better understanding of the rules and mechanisms that underlie such modifications has been limited due to the difficulties associated with simultaneously studying plasticity at multiple synaptic inputs. Here, we provide a solution to this problem by combining cutting-edge high-density microelectrode array (HD-MEA) technology with the patch-clamp technique. While the latter allows for accurate measurement of postsynaptic currents or potentials, evoked by individual synaptic activation, the HD-MEA technology provides large-scale information about unit activity and allows for selective stimulation of neurons, including multiple presynaptic cells. The proposed approach has been applied to comprehensively examine forms of homeostatic plasticity – a collection of crucial processes acting at different temporal scales in order to stabilize neuronal firing rates. We report on a characterization of classic synaptic scaling operating in mature cortical networks and propose a novel model for the study of homeostatic plasticity during natural network states. }, keywords = {HD-MEA}, pubstate = {published}, tppubtype = {conference} } Close Synaptic efficacy and synapse number of monosynaptic connections between neurons are often regulated by the spiking activity of the respective pre- and postsynaptic cell. Progress towards a better understanding of the rules and mechanisms that underlie such modifications has been limited due to the difficulties associated with simultaneously studying plasticity at multiple synaptic inputs. Here, we provide a solution to this problem by combining cutting-edge high-density microelectrode array (HD-MEA) technology with the patch-clamp technique. While the latter allows for accurate measurement of postsynaptic currents or potentials, evoked by individual synaptic activation, the HD-MEA technology provides large-scale information about unit activity and allows for selective stimulation of neurons, including multiple presynaptic cells. The proposed approach has been applied to comprehensively examine forms of homeostatic plasticity – a collection of crucial processes acting at different temporal scales in order to stabilize neuronal firing rates. We report on a characterization of classic synaptic scaling operating in mature cortical networks and propose a novel model for the study of homeostatic plasticity during natural network states. Close https://www.frontiersin.org/10.3389/conf.fncel.2018.38.00085/5473/MEA_Meeting_20[...] doi:10.3389/conf.fncel.2018.38.00085 Close
	da Drinnenberg Antonia; Franke, Felix; Morikawa Rei Jüttner; Hillier Daniel; Hantz Peter; Hierlemann Andreas; Azeredo Silveira Rava; Roska Botond K; How diverse retinal functions arise from feedback at the first visual synapse Journal Article Neuron, 99 (1), pp. 117-134, 2018. Abstract \| Links \| BibTeX \| タグ: Retina @article{Drinnenberg2018, title = {How diverse retinal functions arise from feedback at the first visual synapse}, author = {Drinnenberg, Antonia; Franke, Felix; Morikawa, Rei K; Jüttner; Hillier, Daniel; Hantz, Peter; Hierlemann, Andreas; Azeredo da Silveira, Rava; Roska, Botond}, url = {https://www.cell.com/neuron/fulltext/S0896-6273(18)30469-0}, doi = {10.1016/j.neuron.2018.06.001}, year = {2018}, date = {2018-06-21}, journal = {Neuron}, volume = {99}, number = {1}, pages = {117-134}, abstract = {Many brain regions contain local interneurons of distinct types. How does an interneuron type contribute to the input-output transformations of a given brain region? We addressed this question in the mouse retina by chemogenetically perturbing horizontal cells, an interneuron type providing feedback at the first visual synapse, while monitoring the light-driven spiking activity in thousands of ganglion cells, the retinal output neurons. We uncovered six reversible perturbation-induced effects in the response dynamics and response range of ganglion cells. The effects were enhancing or suppressive, occurred in different response epochs, and depended on the ganglion cell type. A computational model of the retinal circuitry reproduced all perturbation-induced effects and led us to assign specific functions to horizontal cells with respect to different ganglion cell types. Our combined experimental and theoretical work reveals how a single interneuron type can differentially shape the dynamical properties of distinct output channels of a brain region.}, keywords = {Retina}, pubstate = {published}, tppubtype = {article} } Close Many brain regions contain local interneurons of distinct types. How does an interneuron type contribute to the input-output transformations of a given brain region? We addressed this question in the mouse retina by chemogenetically perturbing horizontal cells, an interneuron type providing feedback at the first visual synapse, while monitoring the light-driven spiking activity in thousands of ganglion cells, the retinal output neurons. We uncovered six reversible perturbation-induced effects in the response dynamics and response range of ganglion cells. The effects were enhancing or suppressive, occurred in different response epochs, and depended on the ganglion cell type. A computational model of the retinal circuitry reproduced all perturbation-induced effects and led us to assign specific functions to horizontal cells with respect to different ganglion cell types. Our combined experimental and theoretical work reveals how a single interneuron type can differentially shape the dynamical properties of distinct output channels of a brain region. Close https://www.cell.com/neuron/fulltext/S0896-6273(18)30469-0 doi:10.1016/j.neuron.2018.06.001 Close
	Fiscella, Michele; Leary, Noelle; Ronchi, Silvia; Hierlemann, Andreas Electrophysiological phenotype characterization of human iPSC-derived dopaminergic neuronal lines by means of high-resolution microelelectrode arrays Conference W-2151 , International Society for Stem Cell Research (ISSCR) Annual Meeting Melbourne, Australia, 2018. Abstract \| Links \| BibTeX \| タグ: HD-MEA, IPSC @conference{Fiscella2018b, title = {Electrophysiological phenotype characterization of human iPSC-derived dopaminergic neuronal lines by means of high-resolution microelelectrode arrays}, author = {Michele Fiscella and Noelle Leary and Silvia Ronchi and Andreas Hierlemann }, url = {http://www.isscr.org/docs/default-source/2018-melbourne-ann-mtng/66670-isscr-abstracts_with-links.pdf?sfvrsn=4&utm_source=ISSCR-Informz&utm_medium=email&utm_campaign=default}, year = {2018}, date = {2018-06-20}, volume = {W-2151}, address = {Melbourne, Australia}, organization = {International Society for Stem Cell Research (ISSCR) Annual Meeting}, abstract = {High-resolution-microelectrode-array (MEA) technology enables to study neuronal dynamics at different scales, ranging from axonal physiology to network connectivity (Müller et. al, Lab on a Chip, 2015). We have used this MEA technology to characterize and compare the electrical phenotypes of commercially available human dopaminergic neurons (iCell DopaNeurons, MyCell DopaNeurons A53T α-synuclein, Cellular Dynamics International, Madison, WI, US). Furthermore, we have studied the effect of human astrocytes (iCell Astrocytes, Cellular Dynamics International, Madison, WI, US) on neural culture development. Astrocyte/neuron co- cultures showed higher signal amplitudes and higher firing rates than neural cultures without astrocytes. Adding astrocytes to neural cultures changed the whole culture morphology by promoting cell clustering. Interestingly, astrocyte/neuron co-cultures showed a lower sample-to-sample variability across multiple MEA recordings compared to neural cultures without astrocytes. We compared action potential propagation velocities along axons between dopaminergic A53T α-synuclein neurons and the wild-type isogenic control cell line. We found that in both, wild-type and disease model neurons, axonal action potential propagation velocities were lower than in rat primary cortical neurons. Furthermore, we found different axonal action potential velocity development profiles of A53T α-synuclein dopaminergic neurons and the wild-type counterpart. Finally, we were able to precisely evoke action potentials in individual single human neurons by subcellular- resolution electrical stimulation. High-resolution MEA systems enable to access novel electrophysiological parameters of iPSC-derived neurons, which can be potentially used as biomarkers for phenotype screening and drug testing.}, keywords = {HD-MEA, IPSC}, pubstate = {published}, tppubtype = {conference} } Close High-resolution-microelectrode-array (MEA) technology enables to study neuronal dynamics at different scales, ranging from axonal physiology to network connectivity (Müller et. al, Lab on a Chip, 2015). We have used this MEA technology to characterize and compare the electrical phenotypes of commercially available human dopaminergic neurons (iCell DopaNeurons, MyCell DopaNeurons A53T α-synuclein, Cellular Dynamics International, Madison, WI, US). Furthermore, we have studied the effect of human astrocytes (iCell Astrocytes, Cellular Dynamics International, Madison, WI, US) on neural culture development. Astrocyte/neuron co- cultures showed higher signal amplitudes and higher firing rates than neural cultures without astrocytes. Adding astrocytes to neural cultures changed the whole culture morphology by promoting cell clustering. Interestingly, astrocyte/neuron co-cultures showed a lower sample-to-sample variability across multiple MEA recordings compared to neural cultures without astrocytes. We compared action potential propagation velocities along axons between dopaminergic A53T α-synuclein neurons and the wild-type isogenic control cell line. We found that in both, wild-type and disease model neurons, axonal action potential propagation velocities were lower than in rat primary cortical neurons. Furthermore, we found different axonal action potential velocity development profiles of A53T α-synuclein dopaminergic neurons and the wild-type counterpart. Finally, we were able to precisely evoke action potentials in individual single human neurons by subcellular- resolution electrical stimulation. High-resolution MEA systems enable to access novel electrophysiological parameters of iPSC-derived neurons, which can be potentially used as biomarkers for phenotype screening and drug testing. Close http://www.isscr.org/docs/default-source/2018-melbourne-ann-mtng/66670-isscr-abs[...] Close
	Bakkum Douglas J; Radivojevic, Milos; Obien Marie Engelene; Jaeckel David; Frey Urs; Takahashi Hirokazu; Hierlemann Andreas The axon initial segment drives the neuron's extracellular action potential Journal Article bioRxiv, pp. 1-30, 2018. Abstract \| Links \| BibTeX \| タグ: ETH-CMOS-MEA @article{Bakkum2018, title = {The axon initial segment drives the neuron's extracellular action potential}, author = {Bakkum, Douglas J; Radivojevic, Milos; Obien, Marie Engelene; Jaeckel, David; Frey, Urs; Takahashi, Hirokazu; Hierlemann, Andreas }, url = {https://www.biorxiv.org/content/early/2018/02/16/266734}, doi = {10.1101/266734 }, year = {2018}, date = {2018-02-16}, journal = {bioRxiv}, pages = {1-30}, abstract = {Extracellular voltage fields produced by a neuron's action potentials provide a primary means for studying neuron function, yet their biophysical sources remain ambiguous. The neuron's soma and dendrites are thought to drive the extracellular action potential (EAP), while the axon is usually ignored. However, by recording voltages of single neurons in dissociated rat cortical cultures and Purkinje cells in acute mouse cerebellar slices at hundreds of sites, we find instead that the axon initial segment dominates the EAP, and, surprisingly, the soma shows little or no influence. As expected, this signal has negative polarity (charge entering the cell) and initiates at the distal end. Interestingly, signals with positive polarity (charge exiting the cell) occur near some but not all dendritic branches and occur after a delay. Such basic knowledge about which neuronal compartments contribute to the extracellular voltage field is important for interpreting results from all electrical readout schemes. Moreover, this finding shows that changes in the AIS position and function can be observed in high spatiotemporal detail by means of high-density extracellular electrophysiology.}, keywords = {ETH-CMOS-MEA}, pubstate = {published}, tppubtype = {article} } Close Extracellular voltage fields produced by a neuron's action potentials provide a primary means for studying neuron function, yet their biophysical sources remain ambiguous. The neuron's soma and dendrites are thought to drive the extracellular action potential (EAP), while the axon is usually ignored. However, by recording voltages of single neurons in dissociated rat cortical cultures and Purkinje cells in acute mouse cerebellar slices at hundreds of sites, we find instead that the axon initial segment dominates the EAP, and, surprisingly, the soma shows little or no influence. As expected, this signal has negative polarity (charge entering the cell) and initiates at the distal end. Interestingly, signals with positive polarity (charge exiting the cell) occur near some but not all dendritic branches and occur after a delay. Such basic knowledge about which neuronal compartments contribute to the extracellular voltage field is important for interpreting results from all electrical readout schemes. Moreover, this finding shows that changes in the AIS position and function can be observed in high spatiotemporal detail by means of high-density extracellular electrophysiology. Close https://www.biorxiv.org/content/early/2018/02/16/266734 doi:10.1101/266734 Close
2017
	Viswam, Vijay; Obien, Marie Engelene J; Frey, Urs; Franke, Felix; Hierlemann, Andreas Acquisition of Bioelectrical Signals with Small Electrodes Conference 2017 IEEE Biomedical Circuits and Systems Conference (BioCAS) Turin, Italy, 2017. Abstract \| Links \| BibTeX \| タグ: Electrodes, ETH-CMOS-MEA @conference{Viswam2017, title = {Acquisition of Bioelectrical Signals with Small Electrodes}, author = {Vijay Viswam and Marie Engelene J. Obien and Urs Frey and Felix Franke and Andreas Hierlemann}, url = {https://ieeexplore.ieee.org/document/8325216}, doi = {10.1109/BIOCAS.2017.8325216}, year = {2017}, date = {2017-10-19}, address = {Turin, Italy}, organization = {2017 IEEE Biomedical Circuits and Systems Conference (BioCAS)}, abstract = {Although the mechanisms of recording bioelectrical signals from different types of electrogenic cells (neurons, cardiac cells etc.) by means of planar metal electrodes have been extensively studied, the recording characteristics and conditions for very small electrode sizes are not yet established. Here, we present a combined experimental and computational approach to elucidate, how the electrode size influences the recorded signals, and how inherent properties of the electrode, such as impedance, noise, and transmission characteristics shape the signal. We demonstrate that good quality recordings can be achieved with electrode diameters of less than 10 μm, provided that impedance reduction measures have been implemented and provided that a set of requirements for signal amplification has been met.}, keywords = {Electrodes, ETH-CMOS-MEA}, pubstate = {published}, tppubtype = {conference} } Close Although the mechanisms of recording bioelectrical signals from different types of electrogenic cells (neurons, cardiac cells etc.) by means of planar metal electrodes have been extensively studied, the recording characteristics and conditions for very small electrode sizes are not yet established. Here, we present a combined experimental and computational approach to elucidate, how the electrode size influences the recorded signals, and how inherent properties of the electrode, such as impedance, noise, and transmission characteristics shape the signal. We demonstrate that good quality recordings can be achieved with electrode diameters of less than 10 μm, provided that impedance reduction measures have been implemented and provided that a set of requirements for signal amplification has been met. Close https://ieeexplore.ieee.org/document/8325216 doi:10.1109/BIOCAS.2017.8325216 Close
	Radivojevic, Milos; Franke, Felix; Altermatt, Michael; Müller, Jan; Hierlemann, Andreas; Bakkum, Douglas J Tracking individual action potentials throughout mammalian axonal arbors Journal Article eLife, 6 , pp. 1-23, 2017, ISSN: 2050-084X. Abstract \| Links \| BibTeX \| タグ: Data Analysis, ETH-CMOS-MEA, Neuronal Networks, Stimulation @article{Radivojevic2017, title = {Tracking individual action potentials throughout mammalian axonal arbors}, author = {Milos Radivojevic and Felix Franke and Michael Altermatt and Jan Müller and Andreas Hierlemann and Douglas J Bakkum}, url = {https://elifesciences.org/articles/30198}, doi = {10.7554/eLife.30198}, issn = {2050-084X}, year = {2017}, date = {2017-10-09}, journal = {eLife}, volume = {6}, pages = {1-23}, abstract = {Axons are neuronal processes specialized for conduction of action potentials (APs). The timing and temporal precision of APs when they reach each of the synapses are fundamentally important for information processing in the brain. Due to small diameters of axons, direct recording of single AP transmission is challenging. Consequently, most knowledge about axonal conductance derives from modeling studies or indirect measurements. We demonstrate a method to noninvasively and directly record individual APs propagating along millimeter-length axonal arbors in cortical cultures with hundreds of microelectrodes at microsecond temporal resolution. We find that cortical axons conduct single APs with high temporal precision (~100 µs arrival time jitter per mm length) and reliability: in more than 8,000,000 recorded APs, we did not observe any conduction or branch-point failures. Upon high-frequency stimulation at 100 Hz, successive became slower, and their arrival time precision decreased by 20% and 12% for the 100th AP, respectively.}, keywords = {Data Analysis, ETH-CMOS-MEA, Neuronal Networks, Stimulation}, pubstate = {published}, tppubtype = {article} } Close Axons are neuronal processes specialized for conduction of action potentials (APs). The timing and temporal precision of APs when they reach each of the synapses are fundamentally important for information processing in the brain. Due to small diameters of axons, direct recording of single AP transmission is challenging. Consequently, most knowledge about axonal conductance derives from modeling studies or indirect measurements. We demonstrate a method to noninvasively and directly record individual APs propagating along millimeter-length axonal arbors in cortical cultures with hundreds of microelectrodes at microsecond temporal resolution. We find that cortical axons conduct single APs with high temporal precision (~100 µs arrival time jitter per mm length) and reliability: in more than 8,000,000 recorded APs, we did not observe any conduction or branch-point failures. Upon high-frequency stimulation at 100 Hz, successive became slower, and their arrival time precision decreased by 20% and 12% for the 100th AP, respectively. Close https://elifesciences.org/articles/30198 doi:10.7554/eLife.30198 Close
	Tajima Satohiro; Mita, Takeshi; Bakkum Douglas Takahashi Hirokazu; Toyoizumi Taro J; Locally embedded presages of global network bursts Journal Article National Academy of Sciences, pp. 1-6, 2017, ISSN: 0027-8424. Abstract \| Links \| BibTeX \| タグ: Neuronal Networks @article{Tajima2017, title = {Locally embedded presages of global network bursts}, author = {Tajima, Satohiro; Mita, Takeshi; Bakkum, Douglas J; Takahashi, Hirokazu; Toyoizumi, Taro}, editor = {Sejnowski, Terrence J}, url = {http://www.pnas.org/content/114/36/9517}, doi = {10.1073/pnas.1705981114 }, issn = {0027-8424}, year = {2017}, date = {2017-08-18}, journal = {National Academy of Sciences}, pages = {1-6}, abstract = {Spontaneous, synchronous bursting of neural population is a widely observed phenomenon in nervous networks, which is considered important for functions and dysfunctions of the brain. However, how the global synchrony across a large number of neurons emerges from an initially nonbursting network state is not fully understood. In this study, we develop a state-space reconstruction method combined with high-resolution recordings of cultured neurons. This method extracts deterministic signatures of upcoming global bursts in “local” dynamics of individual neurons during nonbursting periods. We find that local information within a single-cell time series can compare with or even outperform the global mean-field activity for predicting future global bursts. Moreover, the intercell variability in the burst predictability is found to reflect the network structure realized in the nonbursting periods. These findings suggest that deterministic local dynamics can predict seemingly stochastic global events in self-organized networks, implying the potential applications of the present methodology to detecting locally concentrated early warnings of spontaneous seizure occurrence in the brain.}, keywords = {Neuronal Networks}, pubstate = {published}, tppubtype = {article} } Close Spontaneous, synchronous bursting of neural population is a widely observed phenomenon in nervous networks, which is considered important for functions and dysfunctions of the brain. However, how the global synchrony across a large number of neurons emerges from an initially nonbursting network state is not fully understood. In this study, we develop a state-space reconstruction method combined with high-resolution recordings of cultured neurons. This method extracts deterministic signatures of upcoming global bursts in “local” dynamics of individual neurons during nonbursting periods. We find that local information within a single-cell time series can compare with or even outperform the global mean-field activity for predicting future global bursts. Moreover, the intercell variability in the burst predictability is found to reflect the network structure realized in the nonbursting periods. These findings suggest that deterministic local dynamics can predict seemingly stochastic global events in self-organized networks, implying the potential applications of the present methodology to detecting locally concentrated early warnings of spontaneous seizure occurrence in the brain. Close http://www.pnas.org/content/114/36/9517 doi:10.1073/pnas.1705981114 Close
	Shein-Idelson, Mark; Pammer, Lorenz; Hemberger, Mike; Laurent, Gilles Large-scale mapping of cortical synaptic projections with extracellular electrode arrays Journal Article Nature Methods, 14 (9), pp. 882–889, 2017, ISSN: 1548-7091. Abstract \| Links \| BibTeX \| タグ: Brain Slice, MaxOne, Neuronal Networks @article{Shein-Idelson2017, title = {Large-scale mapping of cortical synaptic projections with extracellular electrode arrays}, author = {Mark Shein-Idelson and Lorenz Pammer and Mike Hemberger and Gilles Laurent}, url = {http://www.nature.com/doifinder/10.1038/nmeth.4393}, doi = {10.1038/nmeth.4393}, issn = {1548-7091}, year = {2017}, date = {2017-08-14}, journal = {Nature Methods}, volume = {14}, number = {9}, pages = {882--889}, abstract = {Understanding circuit computation in the nervous system requires sampling activity over large neural populations and maximizing the number of features that can be extracted. By combining planar arrays of extracellular electrodes with the three-layered cortex of turtles, we show that synaptic signals induced along individual axons as well as action potentials can be easily captured. Two types of information can be extracted from these signals, the neuronal subtype (inhibitory or excitatory)—whose identification is more reliable than with traditional measures such as action potential width—and a (partial) spatial map of functional axonal projections from individual neurons. Because our approach is algorithmic, it can be carried out in parallel on hundreds of simultaneously recorded neurons. Combining our approach with soma triangulation, we reveal an axonal projection bias among a population of pyramidal neurons in turtle cortex and confirm this bias through anatomical reconstructions.}, keywords = {Brain Slice, MaxOne, Neuronal Networks}, pubstate = {published}, tppubtype = {article} } Close Understanding circuit computation in the nervous system requires sampling activity over large neural populations and maximizing the number of features that can be extracted. By combining planar arrays of extracellular electrodes with the three-layered cortex of turtles, we show that synaptic signals induced along individual axons as well as action potentials can be easily captured. Two types of information can be extracted from these signals, the neuronal subtype (inhibitory or excitatory)—whose identification is more reliable than with traditional measures such as action potential width—and a (partial) spatial map of functional axonal projections from individual neurons. Because our approach is algorithmic, it can be carried out in parallel on hundreds of simultaneously recorded neurons. Combining our approach with soma triangulation, we reveal an axonal projection bias among a population of pyramidal neurons in turtle cortex and confirm this bias through anatomical reconstructions. Close http://www.nature.com/doifinder/10.1038/nmeth.4393 doi:10.1038/nmeth.4393 Close
	Obien, Marie Engelene J; Zorzi, Giulio; Hierlemann, Andreas Mapping neuron cluster development based on axonal action potential propagation Conference The 40th Annual Meeting of the Japan Neuroscience Society Chiba, Japan, 2017. BibTeX \| タグ: Action Potential, Neuronal Networks @conference{Obien2017, title = {Mapping neuron cluster development based on axonal action potential propagation}, author = {Marie Engelene J. Obien and Giulio Zorzi and Andreas Hierlemann}, year = {2017}, date = {2017-07-20}, address = {Chiba, Japan}, organization = {The 40th Annual Meeting of the Japan Neuroscience Society}, keywords = {Action Potential, Neuronal Networks}, pubstate = {published}, tppubtype = {conference} } Close
	Diggelmann, Roland; Fiscella, Michele; Hierlemann, Andreas; Franke, Felix Pre-whitening as a means to improve dimensionality reduction and simplify clustering in spike-sorters for multi-electrode recordings Conference 26th Annual Computational Neuroscience Meeting (CNS2017) Antwerp, Belgium , 2017. Abstract \| Links \| BibTeX \| タグ: Spike Sorting @conference{Diggelmann2017, title = {Pre-whitening as a means to improve dimensionality reduction and simplify clustering in spike-sorters for multi-electrode recordings}, author = {Roland Diggelmann and Michele Fiscella and Andreas Hierlemann and Felix Franke}, url = {https://bmcneurosci.biomedcentral.com/articles/10.1186/s12868-017-0371-2}, year = {2017}, date = {2017-07-15}, address = {Antwerp, Belgium }, organization = {26th Annual Computational Neuroscience Meeting (CNS2017)}, abstract = {Spike sorting is the process to extract single neuronal activity from extracellular recordings. It makes use of the fact that spikes from a single neuron feature highly similar waveforms, whereas spikes from different neurons have different waveforms. Clustering algorithms are used to find groups of similar spikes that putatively originated from the same neuron. However, since spike waveforms especially in multi-electrode recordings can have a high dimensionality, their dimensionality needs to be reduced before clustering. Principal component analysis (PCA) is one of the most commonly employed dimensionality reduction methods for this purpose [1]. It reduces the dimensions to those where the variance of the data was highest, presumably those along which the waveforms of separate neurons differ most strongly, However, if the noise is not uniform in all dimensions, high variability can also mean high noise, which would render a dimension useless for discrimination. We, therefore, propose an additional pre-whitening step before PCA and discuss two beneficial effects on the subsequent clustering. We illustrate these effects by using spikes from retinal ganglion cells recorded with high-density multi-electrode arrays (HD-MEA).}, keywords = {Spike Sorting}, pubstate = {published}, tppubtype = {conference} } Close Spike sorting is the process to extract single neuronal activity from extracellular recordings. It makes use of the fact that spikes from a single neuron feature highly similar waveforms, whereas spikes from different neurons have different waveforms. Clustering algorithms are used to find groups of similar spikes that putatively originated from the same neuron. However, since spike waveforms especially in multi-electrode recordings can have a high dimensionality, their dimensionality needs to be reduced before clustering. Principal component analysis (PCA) is one of the most commonly employed dimensionality reduction methods for this purpose [1]. It reduces the dimensions to those where the variance of the data was highest, presumably those along which the waveforms of separate neurons differ most strongly, However, if the noise is not uniform in all dimensions, high variability can also mean high noise, which would render a dimension useless for discrimination. We, therefore, propose an additional pre-whitening step before PCA and discuss two beneficial effects on the subsequent clustering. We illustrate these effects by using spikes from retinal ganglion cells recorded with high-density multi-electrode arrays (HD-MEA). Close https://bmcneurosci.biomedcentral.com/articles/10.1186/s12868-017-0371-2 Close
	Viswam, Vijay; Bounik, Raziyeh; Shadmani, Amir; Dragas, Jelena; Obien, Marie; Müller, Jan; Chen, Yihui; Hierlemann1, Andreas High-density mapping of brain slices using a large multi-functional high-density CMOS microelectrode array system Conference 2017 19th International Conference on Solid-State Sensors, Actuators and Microsystems (TRANSDUCERS) 2017. Abstract \| Links \| BibTeX \| タグ: ETH-CMOS-MEA @conference{Viswam2017c, title = {High-density mapping of brain slices using a large multi-functional high-density CMOS microelectrode array system}, author = {Vijay Viswam and Raziyeh Bounik and Amir Shadmani and Jelena Dragas and Marie Obien and Jan Müller and Yihui Chen and Andreas Hierlemann1}, url = {https://ieeexplore.ieee.org/document/7994006}, doi = {10.1109/TRANSDUCERS.2017.7994006}, year = {2017}, date = {2017-06-18}, organization = {2017 19th International Conference on Solid-State Sensors, Actuators and Microsystems (TRANSDUCERS)}, abstract = {We present a CMOS-based high-density microelectrode array (HD-MEA) system that enables high-density mapping of brain slices in-vitrowith multiple readout modalities. The 4.48×2.43 mm2 array consists of 59,760 micro-electrodes at 13.5 μm pitch (5487 electrodes/mm2). The overall system features 2048 action-potential, 32 local-field-potential and 32 current recording channels, 32 impedance-measurement and 28 neurotransmitter-detection channels and 16 voltage/ current stimulation channels. The system enables real-time and label-free monitoring of position, size, morphology and electrical activity of brain slices.}, keywords = {ETH-CMOS-MEA}, pubstate = {published}, tppubtype = {conference} } Close We present a CMOS-based high-density microelectrode array (HD-MEA) system that enables high-density mapping of brain slices in-vitrowith multiple readout modalities. The 4.48×2.43 mm2 array consists of 59,760 micro-electrodes at 13.5 μm pitch (5487 electrodes/mm2). The overall system features 2048 action-potential, 32 local-field-potential and 32 current recording channels, 32 impedance-measurement and 28 neurotransmitter-detection channels and 16 voltage/ current stimulation channels. The system enables real-time and label-free monitoring of position, size, morphology and electrical activity of brain slices. Close https://ieeexplore.ieee.org/document/7994006 doi:10.1109/TRANSDUCERS.2017.7994006 Close
	Viswam, Vijay; Bounik, Raziyeh; Shadmani, Amir; Dragas, Jelena; Obien, Marie Engelene J; Muller, Jan; Chen, Yihui; Hierlemann, Andreas High-density Mapping of Brain Slices Using a Large Multi-functional High-density CMOS Microelectrode Array System Conference 19th International Conference on Solid-State Sensors, Actuators and Microsystems (TRANSDUCERS) Kaohsiung, Taiwan, 2017, ISSN: 2167-0021. Abstract \| Links \| BibTeX \| タグ: Brain Slice, ETH-CMOS-MEA, HD-MEA @conference{Viswam2017b, title = {High-density Mapping of Brain Slices Using a Large Multi-functional High-density CMOS Microelectrode Array System}, author = {Vijay Viswam and Raziyeh Bounik and Amir Shadmani and Jelena Dragas and Marie Engelene J. Obien and Jan Muller and Yihui Chen and Andreas Hierlemann }, url = {https://ieeexplore.ieee.org/abstract/document/7994006}, doi = {10.1109/TRANSDUCERS.2017.7994006}, issn = {2167-0021}, year = {2017}, date = {2017-06-18}, pages = {135-138}, address = {Kaohsiung, Taiwan}, organization = {19th International Conference on Solid-State Sensors, Actuators and Microsystems (TRANSDUCERS)}, abstract = {We present a CMOS-based high-density microelectrode array (HD-MEA) system that enables high-density mapping of brain slices in-vitro with multiple readout modalities. The 4.48×2.43 mm 2 array consists of 59,760 micro-electrodes at 13.5 μm pitch (5487 electrodes/mm 2 ). The overall system features 2048 action-potential, 32 local-field-potential and 32 current recording channels, 32 impedance-measurement and 28 neurotransmitter-detection channels and 16 voltage/current stimulation channels. The system enables real-time and label-free monitoring of position, size, morphology and electrical activity of brain slices.}, keywords = {Brain Slice, ETH-CMOS-MEA, HD-MEA}, pubstate = {published}, tppubtype = {conference} } Close We present a CMOS-based high-density microelectrode array (HD-MEA) system that enables high-density mapping of brain slices in-vitro with multiple readout modalities. The 4.48×2.43 mm 2 array consists of 59,760 micro-electrodes at 13.5 μm pitch (5487 electrodes/mm 2 ). The overall system features 2048 action-potential, 32 local-field-potential and 32 current recording channels, 32 impedance-measurement and 28 neurotransmitter-detection channels and 16 voltage/current stimulation channels. The system enables real-time and label-free monitoring of position, size, morphology and electrical activity of brain slices. Close https://ieeexplore.ieee.org/abstract/document/7994006 doi:10.1109/TRANSDUCERS.2017.7994006 Close
	Frey, Urs; Obien, Marie Engelene J; Muller, Jan; Hierlemann, Andreas Technology Trends and Commercialization of High-density Microelectrode Arrays for Advanced In-vitro Electrophysiology Conference IEEE International Symposium on Circuits and Systems (ISCAS Baltimore, MD, USA, 2017, ISSN: 2379-447X. Abstract \| Links \| BibTeX \| タグ: HD-MEA, In-Vitro @conference{Frey2017, title = {Technology Trends and Commercialization of High-density Microelectrode Arrays for Advanced In-vitro Electrophysiology}, author = {Urs Frey and Marie Engelene J. Obien and Jan Muller and Andreas Hierlemann}, url = {https://ieeexplore.ieee.org/document/8050215/}, doi = {10.1109/ISCAS.2017.8050215}, issn = {2379-447X}, year = {2017}, date = {2017-05-28}, address = {Baltimore, MD, USA}, organization = {IEEE International Symposium on Circuits and Systems (ISCAS}, abstract = {Microelectrode arrays (MEAs) enable fast and high-throughput readout of cell's electrical signals. MEAs are currently used for phenotype characterization and drug toxicity/efficacy testing with iPSC-derived neurons and cardiomyocytes. A key advantage of MEAs is the capability to record and stimulate individual neurons at multiple sites simultaneously. We will present ongoing advancements of MEA technology, with a focus on achieving higher quality recordings by means of monolithic co-integration of circuitry on chip by using CMOS technology [1]. Such high-density MEAs with more than 3000 electrodes per mm2 are a suitable tool for capturing neuronal activity across various scales, including axons, somas, dendrites, entire neurons, and networks.}, keywords = {HD-MEA, In-Vitro}, pubstate = {published}, tppubtype = {conference} } Close Microelectrode arrays (MEAs) enable fast and high-throughput readout of cell's electrical signals. MEAs are currently used for phenotype characterization and drug toxicity/efficacy testing with iPSC-derived neurons and cardiomyocytes. A key advantage of MEAs is the capability to record and stimulate individual neurons at multiple sites simultaneously. We will present ongoing advancements of MEA technology, with a focus on achieving higher quality recordings by means of monolithic co-integration of circuitry on chip by using CMOS technology [1]. Such high-density MEAs with more than 3000 electrodes per mm2 are a suitable tool for capturing neuronal activity across various scales, including axons, somas, dendrites, entire neurons, and networks. Close https://ieeexplore.ieee.org/document/8050215/ doi:10.1109/ISCAS.2017.8050215 Close
	Hillier, Daniel; Fiscella, Michele; Drinnenberg, Antonia; Trenholm, Stuart; Rompani, Santiago B; Raics, Zoltan; Katona, Gergely; Jüttner, Josephine; Hierlemann, Andreas; Rozsa, Balazs; Roska, Botond Causal evidence for retina-dependent and -independent visual motion computations in mouse cortex Journal Article Nature Neuroscience, 20 (7), pp. 960–968, 2017, ISSN: 1097-6256. Abstract \| Links \| BibTeX \| タグ: MaxOne, Retina @article{Hillier2017, title = {Causal evidence for retina-dependent and -independent visual motion computations in mouse cortex}, author = {Daniel Hillier and Michele Fiscella and Antonia Drinnenberg and Stuart Trenholm and Santiago B Rompani and Zoltan Raics and Gergely Katona and Josephine Jüttner and Andreas Hierlemann and Balazs Rozsa and Botond Roska}, url = {http://www.nature.com/doifinder/10.1038/nn.4566}, doi = {10.1038/nn.4566}, issn = {1097-6256}, year = {2017}, date = {2017-05-22}, journal = {Nature Neuroscience}, volume = {20}, number = {7}, pages = {960--968}, abstract = {How neuronal computations in the sensory periphery contribute to computations in the cortex is not well understood. We examined this question in the context of visual-motion processing in the retina and primary visual cortex (V1) of mice. We disrupted retinal direction selectivity, either exclusively along the horizontal axis using FRMD7 mutants or along all directions by ablating starburst amacrine cells, and monitored neuronal activity in layer 2/3 of V1 during stimulation with visual motion. In control mice, we found an over-representation of cortical cells preferring posterior visual motion, the dominant motion direction an animal experiences when it moves forward. In mice with disrupted retinal direction selectivity, the over-representation of posterior-motion-preferring cortical cells disappeared, and their responses at higher stimulus speeds were reduced. This work reveals the existence of two functionally distinct, sensory-periphery-dependent and -independent computations of visual motion in the cortex.}, keywords = {MaxOne, Retina}, pubstate = {published}, tppubtype = {article} } Close How neuronal computations in the sensory periphery contribute to computations in the cortex is not well understood. We examined this question in the context of visual-motion processing in the retina and primary visual cortex (V1) of mice. We disrupted retinal direction selectivity, either exclusively along the horizontal axis using FRMD7 mutants or along all directions by ablating starburst amacrine cells, and monitored neuronal activity in layer 2/3 of V1 during stimulation with visual motion. In control mice, we found an over-representation of cortical cells preferring posterior visual motion, the dominant motion direction an animal experiences when it moves forward. In mice with disrupted retinal direction selectivity, the over-representation of posterior-motion-preferring cortical cells disappeared, and their responses at higher stimulus speeds were reduced. This work reveals the existence of two functionally distinct, sensory-periphery-dependent and -independent computations of visual motion in the cortex. Close http://www.nature.com/doifinder/10.1038/nn.4566 doi:10.1038/nn.4566 Close
	Bullmann Torsten; Radivojevic, Milos; Huber Stefan Deligkaris Kosmas; Hierlemann Andreas; Frey Urs T: Network Analysis Of High-Density Microelectrode Recordings Journal Article bioRxiv , (139436), pp. 1-23, 2017. Abstract \| Links \| BibTeX \| タグ: ETH-CMOS-MEA @article{Bullmann2017, title = {Network Analysis Of High-Density Microelectrode Recordings}, author = {Bullmann, Torsten; Radivojevic, Milos; Huber, Stefan T: Deligkaris, Kosmas; Hierlemann, Andreas; Frey, Urs }, url = {https://www.biorxiv.org/content/early/2017/05/18/139436 }, doi = {10.1101/139436}, year = {2017}, date = {2017-05-18}, journal = {bioRxiv }, number = {139436}, pages = {1-23}, abstract = {Extracellular voltage fields produced by a neuron's action potentials provide a primary means for studying neuron function, yet their biophysical sources remain ambiguous. The neuron's soma and dendrites are thought to drive the extracellular action potential (EAP), while the axon is usually ignored. However, by recording voltages of single neurons in dissociated rat cortical cultures and Purkinje cells in acute mouse cerebellar slices at hundreds of sites, we find instead that the axon initial segment dominates the EAP, and, surprisingly, the soma shows little or no influence. As expected, this signal has negative polarity (charge entering the cell) and initiates at the distal end. Interestingly, signals with positive polarity (charge exiting the cell) occur near some but not all dendritic branches and occur after a delay. Such basic knowledge about which neuronal compartments contribute to the extracellular voltage field is important for interpreting results from all electrical readout schemes. Moreover, this finding shows that changes in the AIS position and function can be observed in high spatiotemporal detail by means of high-density extracellular electrophysiology.}, keywords = {ETH-CMOS-MEA}, pubstate = {published}, tppubtype = {article} } Close Extracellular voltage fields produced by a neuron's action potentials provide a primary means for studying neuron function, yet their biophysical sources remain ambiguous. The neuron's soma and dendrites are thought to drive the extracellular action potential (EAP), while the axon is usually ignored. However, by recording voltages of single neurons in dissociated rat cortical cultures and Purkinje cells in acute mouse cerebellar slices at hundreds of sites, we find instead that the axon initial segment dominates the EAP, and, surprisingly, the soma shows little or no influence. As expected, this signal has negative polarity (charge entering the cell) and initiates at the distal end. Interestingly, signals with positive polarity (charge exiting the cell) occur near some but not all dendritic branches and occur after a delay. Such basic knowledge about which neuronal compartments contribute to the extracellular voltage field is important for interpreting results from all electrical readout schemes. Moreover, this finding shows that changes in the AIS position and function can be observed in high spatiotemporal detail by means of high-density extracellular electrophysiology. Close https://www.biorxiv.org/content/early/2017/05/18/139436 doi:10.1101/139436 Close
	Dragas, Jelena; Viswam, Vijay; Shadmani, Amir; Chen, Yihui; Bounik, Raziyeh; Stettler, Alexander; Radivojevic, Milos; Geissler, Sydney; Obien, Marie Engelene J; Müller, Jan; Hierlemann, Andreas A Multi-Functional Microelectrode Array Featuring 59760 Electrodes, 2048 Electrophysiology Channels, Stimulation, Impedance Measurement and Neurotransmitter Detection Channels Journal Article IEEE journal of solid-state circuits, 52 (6), pp. 1576-1590, 2017, ISSN: 0018-9200. Abstract \| Links \| BibTeX \| タグ: ETH-CMOS-MEA, MEA Technology @article{Dragas2017, title = {A Multi-Functional Microelectrode Array Featuring 59760 Electrodes, 2048 Electrophysiology Channels, Stimulation, Impedance Measurement and Neurotransmitter Detection Channels}, author = {Jelena Dragas and Vijay Viswam and Amir Shadmani and Yihui Chen and Raziyeh Bounik and Alexander Stettler and Milos Radivojevic and Sydney Geissler and Marie Engelene J Obien and Jan Müller and Andreas Hierlemann}, url = {http://ieeexplore.ieee.org/document/7913669/}, doi = {10.1109/JSSC.2017.2686580}, issn = {0018-9200}, year = {2017}, date = {2017-04-27}, journal = {IEEE journal of solid-state circuits}, volume = {52}, number = {6}, pages = {1576-1590}, abstract = {Biological cells are characterized by highly complex phenomena and processes that are, to a great extent, interdependent. To gain detailed insights, devices designed to study cellular phenomena need to enable tracking and manipulation of multiple cell parameters in parallel; they have to provide high signal quality and high spatiotemporal resolution. To this end, we have developed a CMOS-based microelectrode array system that integrates six measurement and stimulation functions, the largest number to date. Moreover, the system features the largest active electrode array area to date (4.48×2.43 mm(2)) to accommodate 59,760 electrodes, while its power consumption, noise characteristics, and spatial resolution (13.5 mum electrode pitch) are comparable to the best state-of-the-art devices. The system includes: 2,048 action-potential (AP, bandwidth: 300 Hz to 10 kHz) recording units, 32 local-field-potential (LFP, bandwidth: 1 Hz to 300 Hz) recording units, 32 current recording units, 32 impedance measurement units, and 28 neurotransmitter detection units, in addition to the 16 dual-mode voltage-only or current/voltage-controlled stimulation units. The electrode array architecture is based on a switch matrix, which allows for connecting any measurement/stimulation unit to any electrode in the array and for performing different measurement/stimulation functions in parallel.}, keywords = {ETH-CMOS-MEA, MEA Technology}, pubstate = {published}, tppubtype = {article} } Close Biological cells are characterized by highly complex phenomena and processes that are, to a great extent, interdependent. To gain detailed insights, devices designed to study cellular phenomena need to enable tracking and manipulation of multiple cell parameters in parallel; they have to provide high signal quality and high spatiotemporal resolution. To this end, we have developed a CMOS-based microelectrode array system that integrates six measurement and stimulation functions, the largest number to date. Moreover, the system features the largest active electrode array area to date (4.48×2.43 mm(2)) to accommodate 59,760 electrodes, while its power consumption, noise characteristics, and spatial resolution (13.5 mum electrode pitch) are comparable to the best state-of-the-art devices. The system includes: 2,048 action-potential (AP, bandwidth: 300 Hz to 10 kHz) recording units, 32 local-field-potential (LFP, bandwidth: 1 Hz to 300 Hz) recording units, 32 current recording units, 32 impedance measurement units, and 28 neurotransmitter detection units, in addition to the 16 dual-mode voltage-only or current/voltage-controlled stimulation units. The electrode array architecture is based on a switch matrix, which allows for connecting any measurement/stimulation unit to any electrode in the array and for performing different measurement/stimulation functions in parallel. Close http://ieeexplore.ieee.org/document/7913669/ doi:10.1109/JSSC.2017.2686580 Close
	Jäckel, David; Bakkum, Douglas J; Russell, Thomas L; Müller, Jan; Radivojevic, Milos; Frey, Urs; Franke, Felix; Hierlemann, Andreas Combination of High-density Microelectrode Array and Patch Clamp Recordings to Enable Studies of Multisynaptic Integration Journal Article Scientific Reports, 7 (1), pp. 978, 2017, ISSN: 2045-2322. Abstract \| Links \| BibTeX \| タグ: ETH-CMOS-MEA, Neuronal Networks @article{Jackel2017, title = {Combination of High-density Microelectrode Array and Patch Clamp Recordings to Enable Studies of Multisynaptic Integration}, author = {David Jäckel and Douglas J Bakkum and Thomas L Russell and Jan Müller and Milos Radivojevic and Urs Frey and Felix Franke and Andreas Hierlemann}, url = {http://www.nature.com/articles/s41598-017-00981-4}, doi = {10.1038/s41598-017-00981-4}, issn = {2045-2322}, year = {2017}, date = {2017-04-20}, journal = {Scientific Reports}, volume = {7}, number = {1}, pages = {978}, abstract = {We present a novel, all-electric approach to record and to precisely control the activity of tens of individual presynaptic neurons. The method allows for parallel mapping of the efficacy of multiple synapses and of the resulting dynamics of postsynaptic neurons in a cortical culture. For the measurements, we combine an extracellular high-density microelectrode array, featuring 11'000 electrodes for extracellular recording and stimulation, with intracellular patch-clamp recording. We are able to identify the contributions of individual presynaptic neurons - including inhibitory and excitatory synaptic inputs - to postsynaptic potentials, which enables us to study dendritic integration. Since the electrical stimuli can be controlled at microsecond resolution, our method enables to evoke action potentials at tens of presynaptic cells in precisely orchestrated sequences of high reliability and minimum jitter. We demonstrate the potential of this method by evoking short- and long-term synaptic plasticity through manipulation of multiple synaptic inputs to a specific neuron.}, keywords = {ETH-CMOS-MEA, Neuronal Networks}, pubstate = {published}, tppubtype = {article} } Close We present a novel, all-electric approach to record and to precisely control the activity of tens of individual presynaptic neurons. The method allows for parallel mapping of the efficacy of multiple synapses and of the resulting dynamics of postsynaptic neurons in a cortical culture. For the measurements, we combine an extracellular high-density microelectrode array, featuring 11'000 electrodes for extracellular recording and stimulation, with intracellular patch-clamp recording. We are able to identify the contributions of individual presynaptic neurons - including inhibitory and excitatory synaptic inputs - to postsynaptic potentials, which enables us to study dendritic integration. Since the electrical stimuli can be controlled at microsecond resolution, our method enables to evoke action potentials at tens of presynaptic cells in precisely orchestrated sequences of high reliability and minimum jitter. We demonstrate the potential of this method by evoking short- and long-term synaptic plasticity through manipulation of multiple synaptic inputs to a specific neuron. Close http://www.nature.com/articles/s41598-017-00981-4 doi:10.1038/s41598-017-00981-4 Close
	Seichepine, Florent; Rothe, Jorg; Dudina, Alexandra; Hierlemann, Andreas; Frey, Urs Dielectrophoresis‐Assisted Integration of 1024 Carbon Nanotube Sensors into a CMOS Microsystem Journal Article Advanced Materials, 29 (17), 2017. Abstract \| Links \| BibTeX \| タグ: ETH-CMOS-MEA @article{Seichepine2017, title = {Dielectrophoresis‐Assisted Integration of 1024 Carbon Nanotube Sensors into a CMOS Microsystem}, author = {Florent Seichepine and Jorg Rothe and Alexandra Dudina and Andreas Hierlemann and Urs Frey}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adma.201606852}, doi = {10.1002/adma.201606852}, year = {2017}, date = {2017-03-15}, journal = {Advanced Materials}, volume = {29}, number = {17}, abstract = {Carbon‐nanotube (CNT)‐based sensors offer the potential to detect single‐molecule events and picomolar analyte concentrations. An important step toward applications of such nanosensors is their integration in large arrays. The availability of large arrays would enable multiplexed and parallel sensing, and the simultaneously obtained sensor signals would facilitate statistical analysis. A reliable method to fabricate an array of 1024 CNT‐based sensors on a fully processed complementary‐metal‐oxide‐semiconductor microsystem is presented. A high‐yield process for the deposition of CNTs from a suspension by means of liquid‐coupled floating‐electrode dielectrophoresis (DEP), which yielded 80% of the sensor devices featuring between one and five CNTs, is developed. The mechanism of floating‐electrode DEP on full arrays and individual devices to understand its self‐limiting behavior is studied. The resistance distributions across the array of CNT devices with respect to different DEP parameters are characterized. The CNT devices are then operated as liquid‐gated CNT field‐effect‐transistors (LG‐CNTFET) in liquid environment. Current dependency to the gate voltage of up to two orders of magnitude is recorded. Finally, the sensors are validated by studying the pH dependency of the LG‐CNTFET conductance and it is demonstrated that 73% of the CNT sensors of a given microsystem show a resistance decrease upon increasing the pH value.}, keywords = {ETH-CMOS-MEA}, pubstate = {published}, tppubtype = {article} } Close Carbon‐nanotube (CNT)‐based sensors offer the potential to detect single‐molecule events and picomolar analyte concentrations. An important step toward applications of such nanosensors is their integration in large arrays. The availability of large arrays would enable multiplexed and parallel sensing, and the simultaneously obtained sensor signals would facilitate statistical analysis. A reliable method to fabricate an array of 1024 CNT‐based sensors on a fully processed complementary‐metal‐oxide‐semiconductor microsystem is presented. A high‐yield process for the deposition of CNTs from a suspension by means of liquid‐coupled floating‐electrode dielectrophoresis (DEP), which yielded 80% of the sensor devices featuring between one and five CNTs, is developed. The mechanism of floating‐electrode DEP on full arrays and individual devices to understand its self‐limiting behavior is studied. The resistance distributions across the array of CNT devices with respect to different DEP parameters are characterized. The CNT devices are then operated as liquid‐gated CNT field‐effect‐transistors (LG‐CNTFET) in liquid environment. Current dependency to the gate voltage of up to two orders of magnitude is recorded. Finally, the sensors are validated by studying the pH dependency of the LG‐CNTFET conductance and it is demonstrated that 73% of the CNT sensors of a given microsystem show a resistance decrease upon increasing the pH value. Close https://onlinelibrary.wiley.com/doi/abs/10.1002/adma.201606852 doi:10.1002/adma.201606852 Close
	Yada, Yuichiro; Mita, Takeshi; Sanada, Akihiro; Yano, Ryuichi; Kanzaki, Ryohei; Bakkum, Douglas J; Hierlemann, Andreas; Takahashi, Hirokazu Development of neural population activity toward self-organized criticality Journal Article Neuroscience, 343 , pp. 55-65, 2017, ISSN: 0306-4522. Abstract \| Links \| BibTeX \| タグ: ETH-CMOS-MEA, Neuronal Networks @article{Takahashi2017, title = {Development of neural population activity toward self-organized criticality}, author = {Yuichiro Yada and Takeshi Mita and Akihiro Sanada and Ryuichi Yano and Ryohei Kanzaki and Douglas J Bakkum and Andreas Hierlemann and Hirokazu Takahashi}, url = {http://www.sciencedirect.com/science/article/pii/S0306452216306522}, doi = {10.1016/j.neuroscience.2016.11.031}, issn = {0306-4522}, year = {2017}, date = {2017-02-20}, journal = {Neuroscience}, volume = {343}, pages = {55-65}, abstract = {Self-organized criticality (SoC), a spontaneous dynamic state established and maintained in networks of moderate complexity, is a universal characteristic of neural systems. Such systems produce cascades of spontaneous activity that are typically characterized by power-law distributions and rich, stable spatiotemporal patterns (i.e., neuronal avalanches). Since the dynamics of the critical state confer advantages in information processing within neuronal networks, it is of great interest to determine how criticality emerges during development. One possible mechanism is developmental, and includes axonal elongation during synaptogenesis and subsequent synaptic pruning in combination with the maturation of GABAergic inhibition (i.e., the integration then fragmentation process). Because experimental evidence for this mechanism remains inconclusive, we studied the developmental variation of neuronal avalanches in dissociated cortical neurons using high-density complementary metal-oxide semiconductor (CMOS) microelectrode arrays (MEAs). The spontaneous activities of nine cultures were monitored using CMOS MEAs from 4 to 30 days in vitro (DIV) at single-cell spatial resolution. While cells were immature, cultures demonstrated random-like patterns of activity and an exponential avalanche size distribution; this distribution was followed by a bimodal distribution, and finally a power-law-like distribution. The bimodal distribution was associated with a large-scale avalanche with a homogeneous spatiotemporal pattern, while the subsequent power-law distribution was associated with diverse patterns. These results suggest that the SoC emerges through a two-step process: the integration process accompanying the characteristic large-scale avalanche and the fragmentation process associated with diverse middle-size avalanches.}, keywords = {ETH-CMOS-MEA, Neuronal Networks}, pubstate = {published}, tppubtype = {article} } Close Self-organized criticality (SoC), a spontaneous dynamic state established and maintained in networks of moderate complexity, is a universal characteristic of neural systems. Such systems produce cascades of spontaneous activity that are typically characterized by power-law distributions and rich, stable spatiotemporal patterns (i.e., neuronal avalanches). Since the dynamics of the critical state confer advantages in information processing within neuronal networks, it is of great interest to determine how criticality emerges during development. One possible mechanism is developmental, and includes axonal elongation during synaptogenesis and subsequent synaptic pruning in combination with the maturation of GABAergic inhibition (i.e., the integration then fragmentation process). Because experimental evidence for this mechanism remains inconclusive, we studied the developmental variation of neuronal avalanches in dissociated cortical neurons using high-density complementary metal-oxide semiconductor (CMOS) microelectrode arrays (MEAs). The spontaneous activities of nine cultures were monitored using CMOS MEAs from 4 to 30 days in vitro (DIV) at single-cell spatial resolution. While cells were immature, cultures demonstrated random-like patterns of activity and an exponential avalanche size distribution; this distribution was followed by a bimodal distribution, and finally a power-law-like distribution. The bimodal distribution was associated with a large-scale avalanche with a homogeneous spatiotemporal pattern, while the subsequent power-law distribution was associated with diverse patterns. These results suggest that the SoC emerges through a two-step process: the integration process accompanying the characteristic large-scale avalanche and the fragmentation process associated with diverse middle-size avalanches. Close http://www.sciencedirect.com/science/article/pii/S0306452216306522 doi:10.1016/j.neuroscience.2016.11.031 Close
2016
	Gong, Wei; Sencar, Jure; Bakkum, Douglas J; Jäckel, David; Obien, Marie Engelene J; Radivojevic, Milos; Hierlemann, Andreas Multiple single-unit long-term tracking on organotypic hippocampal slices using high-density microelectrode arrays Journal Article Frontiers in Neuroscience, 10 , pp. 1-16, 2016, ISSN: 1662453X. Abstract \| Links \| BibTeX \| タグ: Brain Slice, ETH-CMOS-MEA @article{Gong2016, title = {Multiple single-unit long-term tracking on organotypic hippocampal slices using high-density microelectrode arrays}, author = {Wei Gong and Jure Sencar and Douglas J Bakkum and David Jäckel and Marie Engelene J Obien and Milos Radivojevic and Andreas Hierlemann}, url = {https://www.frontiersin.org/articles/10.3389/fnins.2016.00537/full}, doi = {10.3389/fnins.2016.00537}, issn = {1662453X}, year = {2016}, date = {2016-11-22}, journal = {Frontiers in Neuroscience}, volume = {10}, pages = {1-16}, abstract = {A novel system to cultivate and record from organotypic brain slices directly on high-density microelectrode arrays (HD-MEA) was developed. This system allows for continuous recording of electrical activity of specific individual neurons at high spatial resolution while monitoring at the same time, neuronal network activity. For the first time, the electrical activity patterns of single neurons and the corresponding neuronal network in an organotypic hippocampal slice culture were studied during several consecutive weeks at daily intervals. An unsupervised iterative spike-sorting algorithm, based on PCA and k-means clustering, was developed to assign the activities to the single units. Spike-triggered average extracellular waveforms of an action potential recorded across neighboring electrodes, termed ‘footprints' of single-units were generated and tracked over weeks. The developed system offers the potential to study chronic impacts of drugs or genetic modifications on individual neurons in slice preparations over extended times.}, keywords = {Brain Slice, ETH-CMOS-MEA}, pubstate = {published}, tppubtype = {article} } Close A novel system to cultivate and record from organotypic brain slices directly on high-density microelectrode arrays (HD-MEA) was developed. This system allows for continuous recording of electrical activity of specific individual neurons at high spatial resolution while monitoring at the same time, neuronal network activity. For the first time, the electrical activity patterns of single neurons and the corresponding neuronal network in an organotypic hippocampal slice culture were studied during several consecutive weeks at daily intervals. An unsupervised iterative spike-sorting algorithm, based on PCA and k-means clustering, was developed to assign the activities to the single units. Spike-triggered average extracellular waveforms of an action potential recorded across neighboring electrodes, termed ‘footprints' of single-units were generated and tracked over weeks. The developed system offers the potential to study chronic impacts of drugs or genetic modifications on individual neurons in slice preparations over extended times. Close https://www.frontiersin.org/articles/10.3389/fnins.2016.00537/full doi:10.3389/fnins.2016.00537 Close
	Deligkaris, Kosmas; Bullmann, Torsten; Frey, Urs Extracellularly Recorded Somatic and Neuritic Signal Shapes and Classification Algorithms for High-Density Microelectrode Array Electrophysiology Journal Article Frontiers in Neuroscience, 10 , pp. 421, 2016, ISSN: 1662-453X. Abstract \| Links \| BibTeX \| タグ: ETH-CMOS-MEA, Neuronal Networks @article{Frey2016, title = {Extracellularly Recorded Somatic and Neuritic Signal Shapes and Classification Algorithms for High-Density Microelectrode Array Electrophysiology}, author = {Kosmas Deligkaris and Torsten Bullmann and Urs Frey}, url = {https://www.frontiersin.org/article/10.3389/fnins.2016.00421}, doi = {10.3389/fnins.2016.00421}, issn = {1662-453X}, year = {2016}, date = {2016-09-14}, journal = {Frontiers in Neuroscience}, volume = {10}, pages = {421}, abstract = {High-density microelectrode arrays (HDMEA) have been recently introduced to study principles of neural function at high spatial resolution. However, the exact nature of the experimentally observed extracellular action potentials (EAPs) is still incompletely understood. The soma, axon and dendrites of a neuron can all exhibit regenerative action potentials that could be sensed with HDMEA electrodes. Here, we investigate the contribution of distinct neuronal sources of activity in HDMEA recordings from low-density neuronal cultures. We recorded EAPs with HDMEAs having 11,011 electrodes and then fixed and immunostained the cultures with beta3-tubulin for high-resolution fluorescence imaging. Immunofluorescence images overlaid with the activity maps showed EAPs both at neuronal somata and distal neurites. Neuritic EAPs had mostly narrow triphasic shapes, consisting of a positive, a pronounced negative peak and a second positive peak. EAPs near somata had wide monophasic or biphasic shapes with a main negative peak, and following optional positive peak. We show that about 86% of EAP recordings consist of somatic spikes, while the remaining 14% represent neuritic spikes. Furthermore, the adaptation of the waveform shape during bursts of these neuritic spikes suggested that they originate from axons, rather than from dendrites. Our study improves the understanding of HDMEA signals and can aid in the identification of the source of EAPs.}, keywords = {ETH-CMOS-MEA, Neuronal Networks}, pubstate = {published}, tppubtype = {article} } Close High-density microelectrode arrays (HDMEA) have been recently introduced to study principles of neural function at high spatial resolution. However, the exact nature of the experimentally observed extracellular action potentials (EAPs) is still incompletely understood. The soma, axon and dendrites of a neuron can all exhibit regenerative action potentials that could be sensed with HDMEA electrodes. Here, we investigate the contribution of distinct neuronal sources of activity in HDMEA recordings from low-density neuronal cultures. We recorded EAPs with HDMEAs having 11,011 electrodes and then fixed and immunostained the cultures with beta3-tubulin for high-resolution fluorescence imaging. Immunofluorescence images overlaid with the activity maps showed EAPs both at neuronal somata and distal neurites. Neuritic EAPs had mostly narrow triphasic shapes, consisting of a positive, a pronounced negative peak and a second positive peak. EAPs near somata had wide monophasic or biphasic shapes with a main negative peak, and following optional positive peak. We show that about 86% of EAP recordings consist of somatic spikes, while the remaining 14% represent neuritic spikes. Furthermore, the adaptation of the waveform shape during bursts of these neuritic spikes suggested that they originate from axons, rather than from dendrites. Our study improves the understanding of HDMEA signals and can aid in the identification of the source of EAPs. Close https://www.frontiersin.org/article/10.3389/fnins.2016.00421 doi:10.3389/fnins.2016.00421 Close
	Radivojevic, Milos; Jäckel, David; Altermatt, Michael; Müller, Jan; Viswam, Vijay; Hierlemann, Andreas; Bakkum, Douglas J Electrical Identification and Selective Microstimulation of Neuronal Compartments Based on Features of Extracellular Action Potentials Journal Article Scientific Reports, 6 (1), pp. 1-20, 2016, ISSN: 2045-2322. Abstract \| Links \| BibTeX \| タグ: ETH-CMOS-MEA, Neuronal Networks, Stimulation @article{Radivojevic2016, title = {Electrical Identification and Selective Microstimulation of Neuronal Compartments Based on Features of Extracellular Action Potentials}, author = {Milos Radivojevic and David Jäckel and Michael Altermatt and Jan Müller and Vijay Viswam and Andreas Hierlemann and Douglas J Bakkum}, url = {http://www.nature.com/articles/srep31332}, doi = {10.1038/srep31332}, issn = {2045-2322}, year = {2016}, date = {2016-08-11}, journal = {Scientific Reports}, volume = {6}, number = {1}, pages = {1-20}, abstract = {A detailed, high-spatiotemporal-resolution characterization of neuronal responses to local electrical fields and the capability of precise extracellular microstimulation of selected neurons are pivotal for studying and manipulating neuronal activity and circuits in networks and for developing neural prosthetics. Here, we studied cultured neocortical neurons by using high-density microelectrode arrays and optical imaging, complemented by the patch-clamp technique, and with the aim to correlate morphological and electrical features of neuronal compartments with their responsiveness to extracellular stimulation. We developed strategies to electrically identify any neuron in the network, while subcellular spatial resolution recording of extracellular action potential (AP) traces enabled their assignment to the axon initial segment (AIS), axonal arbor and proximal somatodendritic compartments. Stimulation at the AIS required low voltages and provided immediate, selective and reliable neuronal activation, whereas stimulation at the soma required high voltages and produced delayed and unreliable responses. Subthreshold stimulation at the soma depolarized the somatic membrane potential without eliciting APs.}, keywords = {ETH-CMOS-MEA, Neuronal Networks, Stimulation}, pubstate = {published}, tppubtype = {article} } Close A detailed, high-spatiotemporal-resolution characterization of neuronal responses to local electrical fields and the capability of precise extracellular microstimulation of selected neurons are pivotal for studying and manipulating neuronal activity and circuits in networks and for developing neural prosthetics. Here, we studied cultured neocortical neurons by using high-density microelectrode arrays and optical imaging, complemented by the patch-clamp technique, and with the aim to correlate morphological and electrical features of neuronal compartments with their responsiveness to extracellular stimulation. We developed strategies to electrically identify any neuron in the network, while subcellular spatial resolution recording of extracellular action potential (AP) traces enabled their assignment to the axon initial segment (AIS), axonal arbor and proximal somatodendritic compartments. Stimulation at the AIS required low voltages and provided immediate, selective and reliable neuronal activation, whereas stimulation at the soma required high voltages and produced delayed and unreliable responses. Subthreshold stimulation at the soma depolarized the somatic membrane potential without eliciting APs. Close http://www.nature.com/articles/srep31332 doi:10.1038/srep31332 Close
	Lewandowska, Marta K; Radivojevic, Milos; Jäckel, David; Müller, Jan; Hierlemann, Andreas Cortical axons, isolated in channels, display activity-dependent signal modulation as a result of targeted stimulation Journal Article Frontiers in Neuroscience, 10 , pp. 83, 2016, ISSN: 1662453X. Abstract \| Links \| BibTeX \| タグ: MaxOne, Neuronal Networks, u-Tunnels @article{Lewandowska2016, title = {Cortical axons, isolated in channels, display activity-dependent signal modulation as a result of targeted stimulation}, author = {Marta K Lewandowska and Milos Radivojevic and David Jäckel and Jan Müller and Andreas Hierlemann}, url = {https://www.frontiersin.org/articles/10.3389/fnins.2016.00083/full}, doi = {10.3389/fnins.2016.00083}, issn = {1662453X}, year = {2016}, date = {2016-03-07}, journal = {Frontiers in Neuroscience}, volume = {10}, pages = {83}, abstract = {Mammalian cortical axons are extremely thin processes that are difficult to study as a result of their small diameter: they are too narrow to patch while intact, and super-resolution microscopy is needed to resolve single axons. We present a method for studying axonal physiology by pairing a high-density microelectrode array with a microfluidic axonal isolation device, and use it to study activity-dependent modulation of axonal signal propagation evoked by stimulation near the soma. Up to three axonal branches from a single neuron, isolated in different channels, were recorded from simultaneously using 10-20 electrodes per channel. The axonal channels amplified spikes such that propagations of individual signals along tens of electrodes could easily be discerned with high signal to noise. Stimulation from 10 up to 160 Hz demonstrated similar qualitative results from all of the cells studied: extracellular action potential characteristics changed drastically in response to stimulation. Spike height decreased, spike width increased, and latency increased, as a result of reduced propagation velocity, as the number of stimulations and the stimulation frequencies increased. Quantitatively, the strength of these changes manifested itself differently in cells at different frequencies of stimulation. Some cells' signal fidelity fell to 80% already at 10 Hz, while others maintained 80% signal fidelity at 80 Hz. Differences in modulation by axonal branches of the same cell were also seen for different stimulation frequencies, starting at 10 Hz. Potassium ion concentration changes altered the behavior of the cells causing propagation failures at lower concentrations and improving signal fidelity at higher concentrations.}, keywords = {MaxOne, Neuronal Networks, u-Tunnels}, pubstate = {published}, tppubtype = {article} } Close Mammalian cortical axons are extremely thin processes that are difficult to study as a result of their small diameter: they are too narrow to patch while intact, and super-resolution microscopy is needed to resolve single axons. We present a method for studying axonal physiology by pairing a high-density microelectrode array with a microfluidic axonal isolation device, and use it to study activity-dependent modulation of axonal signal propagation evoked by stimulation near the soma. Up to three axonal branches from a single neuron, isolated in different channels, were recorded from simultaneously using 10-20 electrodes per channel. The axonal channels amplified spikes such that propagations of individual signals along tens of electrodes could easily be discerned with high signal to noise. Stimulation from 10 up to 160 Hz demonstrated similar qualitative results from all of the cells studied: extracellular action potential characteristics changed drastically in response to stimulation. Spike height decreased, spike width increased, and latency increased, as a result of reduced propagation velocity, as the number of stimulations and the stimulation frequencies increased. Quantitatively, the strength of these changes manifested itself differently in cells at different frequencies of stimulation. Some cells' signal fidelity fell to 80% already at 10 Hz, while others maintained 80% signal fidelity at 80 Hz. Differences in modulation by axonal branches of the same cell were also seen for different stimulation frequencies, starting at 10 Hz. Potassium ion concentration changes altered the behavior of the cells causing propagation failures at lower concentrations and improving signal fidelity at higher concentrations. Close https://www.frontiersin.org/articles/10.3389/fnins.2016.00083/full doi:10.3389/fnins.2016.00083 Close
	Franke, Felix; Fiscella, Michele; Sevelev, Maksim; Roska, Botond; Hierlemann, Andreas; Azeredo da Silveira, Rava Structures of Neural Correlation and How They Favor Coding Journal Article Neuron, 89 (2), pp. 409-422, 2016, ISSN: 10974199. Abstract \| Links \| BibTeX \| タグ: Data Analysis, ETH-CMOS-MEA, Neuronal Networks, Retina @article{Franke2016, title = {Structures of Neural Correlation and How They Favor Coding}, author = {Felix Franke and Michele Fiscella and Maksim Sevelev and Botond Roska and Andreas Hierlemann and Rava {Azeredo da Silveira}}, url = {http://www.sciencedirect.com/science/article/pii/S0896627315011393?via%3Dihub}, doi = {10.1016/j.neuron.2015.12.037}, issn = {10974199}, year = {2016}, date = {2016-01-20}, journal = {Neuron}, volume = {89}, number = {2}, pages = {409-422}, publisher = {Elsevier Inc.}, abstract = {The neural representation of information suffers from "noise"-the trial-to-trial variability in the response of neurons. The impact of correlated noise upon population coding has been debated, but a direct connection between theory and experiment remains tenuous. Here, we substantiate this connection and propose a refined theoretical picture. Using simultaneous recordings from a population of direction-selective retinal ganglion cells, we demonstrate that coding benefits from noise correlations. The effect is appreciable already in small populations, yet it is a collective phenomenon. Furthermore, the stimulus-dependent structure of correlation is key. We develop simple functional models that capture the stimulus-dependent statistics. We then use them to quantify the performance of population coding, which depends upon interplays of feature sensitivities and noise correlations in the population. Because favorable structures of correlation emerge robustly in circuits with noisy, nonlinear elements, they will arise and benefit coding beyond the confines of retina. Coding in the brain suffers from the variability of neural responses. Using experiment and theory, Franke et al. show that this "noise" comes with a particular structure, which emerges from circuit properties and which counteracts the harmful effect of variability.}, keywords = {Data Analysis, ETH-CMOS-MEA, Neuronal Networks, Retina}, pubstate = {published}, tppubtype = {article} } Close The neural representation of information suffers from "noise"-the trial-to-trial variability in the response of neurons. The impact of correlated noise upon population coding has been debated, but a direct connection between theory and experiment remains tenuous. Here, we substantiate this connection and propose a refined theoretical picture. Using simultaneous recordings from a population of direction-selective retinal ganglion cells, we demonstrate that coding benefits from noise correlations. The effect is appreciable already in small populations, yet it is a collective phenomenon. Furthermore, the stimulus-dependent structure of correlation is key. We develop simple functional models that capture the stimulus-dependent statistics. We then use them to quantify the performance of population coding, which depends upon interplays of feature sensitivities and noise correlations in the population. Because favorable structures of correlation emerge robustly in circuits with noisy, nonlinear elements, they will arise and benefit coding beyond the confines of retina. Coding in the brain suffers from the variability of neural responses. Using experiment and theory, Franke et al. show that this "noise" comes with a particular structure, which emerges from circuit properties and which counteracts the harmful effect of variability. Close http://www.sciencedirect.com/science/article/pii/S0896627315011393?via%3Dihub doi:10.1016/j.neuron.2015.12.037 Close
	Yonehara, Keisuke; Fiscella, Michele; Drinnenberg, Antonia; Esposti, Federico; Trenholm, Stuart; Krol, Jacek; Franke, Felix; Scherf, Brigitte Gross; Kusnyerik, Akos; Müller, Jan; Szabo, Arnold; Jüttner, Josephine; Cordoba, Francisco; Reddy, Ashrithpal Police; Németh, János; Nagy, Zoltán Zsolt; Munier, Francis; Hierlemann, Andreas; Roska, Botond Congenital Nystagmus Gene FRMD7 Is Necessary for Establishing a Neuronal Circuit Asymmetry for Direction Selectivity Journal Article Neuron, 89 (1), pp. 177-193, 2016, ISSN: 10974199. Abstract \| Links \| BibTeX \| タグ: ETH-CMOS-MEA, Retina @article{Yonehara2016, title = {Congenital Nystagmus Gene FRMD7 Is Necessary for Establishing a Neuronal Circuit Asymmetry for Direction Selectivity}, author = {Keisuke Yonehara and Michele Fiscella and Antonia Drinnenberg and Federico Esposti and Stuart Trenholm and Jacek Krol and Felix Franke and Brigitte Gross Scherf and Akos Kusnyerik and Jan Müller and Arnold Szabo and Josephine Jüttner and Francisco Cordoba and Ashrithpal Police Reddy and János Németh and Zoltán Zsolt Nagy and Francis Munier and Andreas Hierlemann and Botond Roska}, url = {http://www.sciencedirect.com/science/article/pii/S0896627315010387?via%3Dihub}, doi = {10.1016/j.neuron.2015.11.032}, issn = {10974199}, year = {2016}, date = {2016-01-06}, journal = {Neuron}, volume = {89}, number = {1}, pages = {177-193}, abstract = {Neuronal circuit asymmetries are important components of brain circuits, but the molecular pathways leading to their establishment remain unknown. Here we found that the mutation of FRMD7, a gene that is defective in human congenital nystagmus, leads to the selective loss of the horizontal optokinetic reflex in mice, as it does in humans. This is accompanied by the selective loss of horizontal direction selectivity in retinal ganglion cells and the transition from asymmetric to symmetric inhibitory input to horizontal direction-selective ganglion cells. In wild-type retinas, we found FRMD7 specifically expressed in starburst amacrine cells, the interneuron type that provides asymmetric inhibition to direction-selective retinal ganglion cells. This work identifies FRMD7 as a key regulator in establishing a neuronal circuit asymmetry, and it suggests the involvement of a specific inhibitory neuron type in the pathophysiology of a neurological disease.}, keywords = {ETH-CMOS-MEA, Retina}, pubstate = {published}, tppubtype = {article} } Close Neuronal circuit asymmetries are important components of brain circuits, but the molecular pathways leading to their establishment remain unknown. Here we found that the mutation of FRMD7, a gene that is defective in human congenital nystagmus, leads to the selective loss of the horizontal optokinetic reflex in mice, as it does in humans. This is accompanied by the selective loss of horizontal direction selectivity in retinal ganglion cells and the transition from asymmetric to symmetric inhibitory input to horizontal direction-selective ganglion cells. In wild-type retinas, we found FRMD7 specifically expressed in starburst amacrine cells, the interneuron type that provides asymmetric inhibition to direction-selective retinal ganglion cells. This work identifies FRMD7 as a key regulator in establishing a neuronal circuit asymmetry, and it suggests the involvement of a specific inhibitory neuron type in the pathophysiology of a neurological disease. Close http://www.sciencedirect.com/science/article/pii/S0896627315010387?via%3Dihub doi:10.1016/j.neuron.2015.11.032 Close
	Viswam, Vijay; Dragas, Jelena; Shadmani, Amir; Chen, Yihui; Stettler, Alexander; Müller, Jan; Hierlemann, Andreas 22.8 Multi-functional microelectrode array system featuring 59,760 electrodes, 2048 electrophysiology channels, impedance and neurotransmitter measurement units Conference 2016 IEEE International Solid-State Circuits Conference (ISSCC), 2016. Abstract \| Links \| BibTeX \| タグ: Action Potential, ETH-CMOS-MEA, HD-MEA, MEA Technology @conference{Viswam2016, title = {22.8 Multi-functional microelectrode array system featuring 59,760 electrodes, 2048 electrophysiology channels, impedance and neurotransmitter measurement units}, author = {Vijay Viswam and Jelena Dragas and Amir Shadmani and Yihui Chen and Alexander Stettler and Jan Müller and Andreas Hierlemann}, url = {http://ieeexplore.ieee.org/document/7418073/}, doi = {10.1109/ISSCC.2016.7418073}, year = {2016}, date = {2016-01-01}, booktitle = {2016 IEEE International Solid-State Circuits Conference (ISSCC)}, journal = {2016 IEEE International Solid-State Circuits Conference (ISSCC)}, abstract = {Various CMOS-based micro-electrode arrays (MEAs) have been developed in recent years for extracellular electrophysiological recording/stimulation of electrogenic cells [1–5]. Mostly two approaches have been used: (i) the activepixel approach (APS) [2–4], which features simultaneous readout of all electrodes, however, at the expense of a comparably high noise level, and (ii) the switchmatrix (SM) approach, which yields better noise performance, whereas only a subset of electrodes (e.g.,1024) is simultaneously read out [5]. All systems feature, at most, voltage recording and/or voltage/current stimulation functionalities.}, keywords = {Action Potential, ETH-CMOS-MEA, HD-MEA, MEA Technology}, pubstate = {published}, tppubtype = {conference} } Close Various CMOS-based micro-electrode arrays (MEAs) have been developed in recent years for extracellular electrophysiological recording/stimulation of electrogenic cells [1–5]. Mostly two approaches have been used: (i) the activepixel approach (APS) [2–4], which features simultaneous readout of all electrodes, however, at the expense of a comparably high noise level, and (ii) the switchmatrix (SM) approach, which yields better noise performance, whereas only a subset of electrodes (e.g.,1024) is simultaneously read out [5]. All systems feature, at most, voltage recording and/or voltage/current stimulation functionalities. Close http://ieeexplore.ieee.org/document/7418073/ doi:10.1109/ISSCC.2016.7418073 Close
2015
	Jones, Ian L; Russell, Thomas L; Farrow, Karl; Fiscella, Michele; Franke, Felix; Müller, Jan; Jäckel, David; Hierlemann, Andreas A method for electrophysiological characterization of hamster retinal ganglion cells using a high-density CMOS microelectrode array Journal Article Frontiers in Neuroscience, 9 , pp. 360, 2015, ISSN: 1662453X. Abstract \| Links \| BibTeX \| タグ: ETH-CMOS-MEA, Retina @article{Jones2015, title = {A method for electrophysiological characterization of hamster retinal ganglion cells using a high-density CMOS microelectrode array}, author = {Ian L Jones and Thomas L Russell and Karl Farrow and Michele Fiscella and Felix Franke and Jan Müller and David Jäckel and Andreas Hierlemann}, url = {https://www.frontiersin.org/articles/10.3389/fnins.2015.00360/full}, doi = {10.3389/fnins.2015.00360}, issn = {1662453X}, year = {2015}, date = {2015-10-13}, journal = {Frontiers in Neuroscience}, volume = {9}, pages = {360}, abstract = {Knowledge of neuronal cell types in the mammalian retina is important for the understanding of human retinal disease and the advancement of sight-restoring technology, such as retinal prosthetic devices. A somewhat less utilized animal model for retinal research is the hamster, which has a visual system that is characterized by an area centralis and a wide visual field with a broad binocular component. The hamster retina is optimally suited for recording on the microelectrode array (MEA), because it intrinsically lies flat on the MEA surface and yields robust, large-amplitude signals. However, information in the literature about hamster retinal ganglion cell functional types is scarce. The goal of our work is to develop a method featuring a high-density (HD) Complementary metal-oxide-semiconductor (CMOS) MEA technology along with a sequence of standardized visual stimuli in order to categorize ganglion cells in isolated Syrian Hamster (Mesocricetus auratus) retina. Since the HD-MEA is capable of recording at a higher spatial resolution than most MEA systems (17.5 um electrode pitch), we capitalized on this feature and were able to record from a large proportion of RGCs within a selected region. Secondly, we chose our stimuli so that they could be run during the experiment without intervention or computation steps. The visual stimulus set was designed to activate the receptive fields of most ganglion cells in parallel and to incorporate various visual features to which different cell types respond uniquely. Based on the ganglion cell responses, basic cell properties were determined: direction selectivity, speed tuning, width tuning, transience and latency. These properties were clustered in order to identify ganglion cell types in the hamster retina. Ultimately, we recorded up to a cell density 2780 cells/mm2 at 2 mm (42°) from the optic nerve head. Using 5 parameters extracted from the responses to visual stimuli, we obtained 7 ganglion cell types.}, keywords = {ETH-CMOS-MEA, Retina}, pubstate = {published}, tppubtype = {article} } Close Knowledge of neuronal cell types in the mammalian retina is important for the understanding of human retinal disease and the advancement of sight-restoring technology, such as retinal prosthetic devices. A somewhat less utilized animal model for retinal research is the hamster, which has a visual system that is characterized by an area centralis and a wide visual field with a broad binocular component. The hamster retina is optimally suited for recording on the microelectrode array (MEA), because it intrinsically lies flat on the MEA surface and yields robust, large-amplitude signals. However, information in the literature about hamster retinal ganglion cell functional types is scarce. The goal of our work is to develop a method featuring a high-density (HD) Complementary metal-oxide-semiconductor (CMOS) MEA technology along with a sequence of standardized visual stimuli in order to categorize ganglion cells in isolated Syrian Hamster (Mesocricetus auratus) retina. Since the HD-MEA is capable of recording at a higher spatial resolution than most MEA systems (17.5 um electrode pitch), we capitalized on this feature and were able to record from a large proportion of RGCs within a selected region. Secondly, we chose our stimuli so that they could be run during the experiment without intervention or computation steps. The visual stimulus set was designed to activate the receptive fields of most ganglion cells in parallel and to incorporate various visual features to which different cell types respond uniquely. Based on the ganglion cell responses, basic cell properties were determined: direction selectivity, speed tuning, width tuning, transience and latency. These properties were clustered in order to identify ganglion cell types in the hamster retina. Ultimately, we recorded up to a cell density 2780 cells/mm2 at 2 mm (42°) from the optic nerve head. Using 5 parameters extracted from the responses to visual stimuli, we obtained 7 ganglion cell types. Close https://www.frontiersin.org/articles/10.3389/fnins.2015.00360/full doi:10.3389/fnins.2015.00360 Close

235 entries « ‹ 4 of 5 › »

2019
	Russell, Thomas L; Zhang, Jichang; Okoniewksi, Michal; Franke, Felix; Bichet, Sandrine; Hierlemann, Andreas Medullary Respiratory Circuit Is Reorganized by a Seasonally-Induced Program in Preparation for Hibernation Journal Article Frontiers in Neuroscience , 13 , 2019, ISSN: 1662-453X. Abstract \| Links \| BibTeX \| タグ: Respiratory Circuit @article{Russell2019, title = {Medullary Respiratory Circuit Is Reorganized by a Seasonally-Induced Program in Preparation for Hibernation }, author = {Thomas L. Russell and Jichang Zhang and Michal Okoniewksi and Felix Franke and Sandrine Bichet and Andreas Hierlemann}, url = {https://www.frontiersin.org/article/10.3389/fnins.2019.00376}, doi = {10.3389/fnins.2019.00376 }, issn = {1662-453X}, year = {2019}, date = {2019-04-26}, journal = {Frontiers in Neuroscience }, volume = {13}, abstract = {Deep hibernators go through several cycles of profound drops in body temperature during the winter season, with core temperatures sometimes reaching near freezing. Yet unlike non-hibernating mammals, they can sustain breathing rhythms. The physiological processes that make this possible are still not understood. In this study, we focused on the medullary Ventral Respiratory Column of a facultative hibernator, the Syrian hamster. Using shortened day-lengths, we induced a "winter-adapted" physiological state, which is a prerequisite for hibernation. When recording electrophysiological signals from acute slices in the winter-adapted pre-Bötzinger complex, spike trains showed higher spike rates, amplitudes, complexity, as well as higher temperature sensitivity, suggesting an increase in connectivity and/or synaptic strength during the winter season. We further examined action potential waveforms and found that the depolarization integral, as measured by the area under the curve, is selectively enhanced in winter-adapted animals. This suggests that a shift in the ion handling kinetics is also being induced by the winter-adaptation program. RNA sequencing of respiratory pre-motor neurons, followed by gene set enrichment analysis, revealed differential regulation and splicing in structural, synaptic, and ion handling genes. Splice junction analysis suggested that differential exon usage is occurring in a select subset of ion handling subunits (ATP1A3, KCNC3, SCN1B), and synaptic structure genes (SNCB, SNCG, RAB3A). Our findings show that the hamster respiratory center undergoes a seasonally-cued alteration in electrophysiological properties, likely protecting against respiratory failure at low temperatures.}, keywords = {Respiratory Circuit}, pubstate = {published}, tppubtype = {article} } Close Deep hibernators go through several cycles of profound drops in body temperature during the winter season, with core temperatures sometimes reaching near freezing. Yet unlike non-hibernating mammals, they can sustain breathing rhythms. The physiological processes that make this possible are still not understood. In this study, we focused on the medullary Ventral Respiratory Column of a facultative hibernator, the Syrian hamster. Using shortened day-lengths, we induced a "winter-adapted" physiological state, which is a prerequisite for hibernation. When recording electrophysiological signals from acute slices in the winter-adapted pre-Bötzinger complex, spike trains showed higher spike rates, amplitudes, complexity, as well as higher temperature sensitivity, suggesting an increase in connectivity and/or synaptic strength during the winter season. We further examined action potential waveforms and found that the depolarization integral, as measured by the area under the curve, is selectively enhanced in winter-adapted animals. This suggests that a shift in the ion handling kinetics is also being induced by the winter-adaptation program. RNA sequencing of respiratory pre-motor neurons, followed by gene set enrichment analysis, revealed differential regulation and splicing in structural, synaptic, and ion handling genes. Splice junction analysis suggested that differential exon usage is occurring in a select subset of ion handling subunits (ATP1A3, KCNC3, SCN1B), and synaptic structure genes (SNCB, SNCG, RAB3A). Our findings show that the hamster respiratory center undergoes a seasonally-cued alteration in electrophysiological properties, likely protecting against respiratory failure at low temperatures. Close https://www.frontiersin.org/article/10.3389/fnins.2019.00376 doi:10.3389/fnins.2019.00376 Close
	Ronchi, Silvia; Fiscella, Michele; Marchetti, Camilla; Viswam, Vijay; Muller, Jan; Frey, Urs; Hierlemann, Andreas Single-Cell Electrical Stimulation Using CMOS-Based High-Density Microelectrode Arrays Journal Article Frontiers in Neuroscience, 13 , 2019, ISSN: 1662-453X . Abstract \| Links \| BibTeX \| タグ: ETH-CMOS-MEA, Stimulation @article{Ronchi2019, title = {Single-Cell Electrical Stimulation Using CMOS-Based High-Density Microelectrode Arrays}, author = {Silvia Ronchi and Michele Fiscella and Camilla Marchetti and Vijay Viswam and Jan Muller and Urs Frey and Andreas Hierlemann}, url = {https://www.frontiersin.org/article/10.3389/fnins.2019.00208 }, doi = {10.3389/fnins.2019.00208 }, issn = {1662-453X }, year = {2019}, date = {2019-03-13}, journal = {Frontiers in Neuroscience}, volume = {13}, abstract = {Non-invasive electrical stimulation can be used to study and control neural activity in the brain or to alleviate somatosensory dysfunctions. One intriguing prospect is to precisely stimulate individual targeted neurons. Here, we investigated single-neuron current and voltage stimulation in vitro using high-density microelectrode arrays featuring 26’400 bidirectional electrodes at a pitch of 17.5 µm and an electrode area of 5 × 9 µm². We determined optimal waveforms, amplitudes and durations for both stimulation modes. Owing to the high spatial resolution of our arrays and the close proximity of the electrodes to the respective neurons, we were able to stimulate the axon initial segments (AIS) with charges of less than 2 picoCoulombs. This resulted in minimal artifact production and reliable readout of stimulation efficiency directly at the soma of the stimulated cell. Stimulation signals as low as 70 mV or 100 nA,with pulse durations as short as 18 µs, yielded measurable action potential initiation and propagation. We found that the required stimulation signal amplitudes decreased with cell growth and development and that stimulation efficiency did not improve at higher electric fields generated by simultaneous multi-electrode stimulation.}, keywords = {ETH-CMOS-MEA, Stimulation}, pubstate = {published}, tppubtype = {article} } Close Non-invasive electrical stimulation can be used to study and control neural activity in the brain or to alleviate somatosensory dysfunctions. One intriguing prospect is to precisely stimulate individual targeted neurons. Here, we investigated single-neuron current and voltage stimulation in vitro using high-density microelectrode arrays featuring 26’400 bidirectional electrodes at a pitch of 17.5 µm and an electrode area of 5 × 9 µm². We determined optimal waveforms, amplitudes and durations for both stimulation modes. Owing to the high spatial resolution of our arrays and the close proximity of the electrodes to the respective neurons, we were able to stimulate the axon initial segments (AIS) with charges of less than 2 picoCoulombs. This resulted in minimal artifact production and reliable readout of stimulation efficiency directly at the soma of the stimulated cell. Stimulation signals as low as 70 mV or 100 nA,with pulse durations as short as 18 µs, yielded measurable action potential initiation and propagation. We found that the required stimulation signal amplitudes decreased with cell growth and development and that stimulation efficiency did not improve at higher electric fields generated by simultaneous multi-electrode stimulation. Close https://www.frontiersin.org/article/10.3389/fnins.2019.00208 doi:10.3389/fnins.2019.00208 Close
	Obien, Marie Engelene J; Hierlemann, Andreas; Frey, Urs Accurate signal-source localization in brain slices by means of high-density microelectrode arrays Journal Article Scientific Reports, 9 (788), 2019. Abstract \| Links \| BibTeX \| タグ: Brain Slice @article{Obien2019, title = {Accurate signal-source localization in brain slices by means of high-density microelectrode arrays}, author = {Marie Engelene J. Obien and Andreas Hierlemann and Urs Frey}, url = {https://www.nature.com/articles/s41598-018-36895-y}, doi = {10.1038/s41598-018-36895-y}, year = {2019}, date = {2019-01-28}, journal = {Scientific Reports}, volume = {9}, number = {788}, abstract = {Extracellular recordings by means of high-density microelectrode arrays (HD-MEAs) have become a powerful tool to resolve subcellular details of single neurons in active networks grown from dissociated cells. To extend the application of this technology to slice preparations, we developed models describing how extracellular signals, produced by neuronal cells in slices, are detected by microelectrode arrays. The models help to analyze and understand the electrical-potential landscape in an in vitro HD-MEA-recording scenario based on point-current sources. We employed two modeling schemes, (i) a simple analytical approach, based on the method of images (MoI), and (ii) an approach, based on finite-element methods (FEM). We compared and validated the models with large-scale, high-spatiotemporal-resolution recordings of slice preparations by means of HD-MEAs. We then developed a model-based localization algorithm and compared the performance of MoI and FEM models. Both models provided accurate localization results and a comparable and negligible systematic error, when the point source was in saline, a condition similar to cell-culture experiments. Moreover, the relative random error in the x-y-z-localization amounted only up to 4.3% for z-distances up to 200 μm from the HD-MEA surface. In tissue, the systematic errors of both, MoI and FEM models were significantly higher, and a pre-calibration was required. Nevertheless, the FEM values proved to be closer to the tissue experimental results, yielding 5.2 μm systematic mean error, compared to 22.0 μm obtained with MoI. These results suggest that the medium volume or “saline height”, the brain slice thickness and anisotropy, and the location of the reference electrode, which were included in the FEM model, considerably affect the extracellular signal and localization performance, when the signal source is at larger distance to the array. After pre-calibration, the relative random error of the z-localization in tissue was only 3% for z-distances up to 200 μm. We then applied the model and related detailed understanding of extracellular recordings to achieve an electrically-guided navigation of a stimulating micropipette, solely based on the measured HD-MEA signals, and managed to target spontaneously active neurons in an acute brain slice for electroporation.}, keywords = {Brain Slice}, pubstate = {published}, tppubtype = {article} } Close Extracellular recordings by means of high-density microelectrode arrays (HD-MEAs) have become a powerful tool to resolve subcellular details of single neurons in active networks grown from dissociated cells. To extend the application of this technology to slice preparations, we developed models describing how extracellular signals, produced by neuronal cells in slices, are detected by microelectrode arrays. The models help to analyze and understand the electrical-potential landscape in an in vitro HD-MEA-recording scenario based on point-current sources. We employed two modeling schemes, (i) a simple analytical approach, based on the method of images (MoI), and (ii) an approach, based on finite-element methods (FEM). We compared and validated the models with large-scale, high-spatiotemporal-resolution recordings of slice preparations by means of HD-MEAs. We then developed a model-based localization algorithm and compared the performance of MoI and FEM models. Both models provided accurate localization results and a comparable and negligible systematic error, when the point source was in saline, a condition similar to cell-culture experiments. Moreover, the relative random error in the x-y-z-localization amounted only up to 4.3% for z-distances up to 200 μm from the HD-MEA surface. In tissue, the systematic errors of both, MoI and FEM models were significantly higher, and a pre-calibration was required. Nevertheless, the FEM values proved to be closer to the tissue experimental results, yielding 5.2 μm systematic mean error, compared to 22.0 μm obtained with MoI. These results suggest that the medium volume or “saline height”, the brain slice thickness and anisotropy, and the location of the reference electrode, which were included in the FEM model, considerably affect the extracellular signal and localization performance, when the signal source is at larger distance to the array. After pre-calibration, the relative random error of the z-localization in tissue was only 3% for z-distances up to 200 μm. We then applied the model and related detailed understanding of extracellular recordings to achieve an electrically-guided navigation of a stimulating micropipette, solely based on the measured HD-MEA signals, and managed to target spontaneously active neurons in an acute brain slice for electroporation. Close https://www.nature.com/articles/s41598-018-36895-y doi:10.1038/s41598-018-36895-y Close
	Dudina, Alexandra; Seichepine, Florent; Chen, Yihui; and Stettler, Alexander; Hierlemann, Andreas; and Frey, Urs Monolithic CMOS sensor platform featuring an array of 9’216 carbon-nanotube-sensor elements and low-noise, wide-bandwidth and wide-dynamic-range readout circuitry Journal Article Sensors and Actuators B: Chemical, 279 , pp. 255-266, 2019. Abstract \| Links \| BibTeX \| タグ: ETH-CMOS-MEA @article{Dudina2019, title = {Monolithic CMOS sensor platform featuring an array of 9’216 carbon-nanotube-sensor elements and low-noise, wide-bandwidth and wide-dynamic-range readout circuitry}, author = {Alexandra Dudina and Florent Seichepine and Yihui Chen and and Alexander Stettler and Andreas Hierlemann and and Urs Frey}, url = {https://www.sciencedirect.com/science/article/pii/S0925400518317672?via%3Dihub}, doi = {10.1016/j.snb.2018.10.004}, year = {2019}, date = {2019-01-15}, journal = {Sensors and Actuators B: Chemical}, volume = {279}, pages = {255-266}, abstract = {We present the design and characterization of a monolithic complementary metal–oxide–semiconductor (CMOS) biosensor platform comprising of a switch-matrix-based array of 9′216 carbon nanotube field-effect transistors (CNTFETs) and associated readout circuitry. The switch-matrix allows for flexible selection and simultaneous routing of 96 sensor elements to the corresponding readout channels. A low-noise, wide-bandwidth, wide-dynamic-range transimpedance continuous-time amplifier architecture has been implemented to facilitate resistance measurements in the range between 50 kΩ and 1 GΩ at a bandwidth of up to 1 MHz. The achieved accuracy of the resistance measurements over the whole range is 4%. The system has been successfully fabricated and tested and shows a noise performance equal to 2.14 pArms at a bandwidth of 1 kHz and 0.84 nArms at a bandwidth of 1 MHz. A batch integration of the CNTFETs has been achieved by using a dielectrophoresis (DEP)–based manipulation technique. The current-voltage curves of CNTFETs have been acquired, and the sensing capabilities of the system have been demonstrated by recording resistance changes of CNTFETs upon exposure to solutions with different pH values and different concentrations of NaCl. The smallest resolvable concentrations for the respective analytes were estimated to amount to 0.025 pH-units and 4 mM NaCl.}, keywords = {ETH-CMOS-MEA}, pubstate = {published}, tppubtype = {article} } Close We present the design and characterization of a monolithic complementary metal–oxide–semiconductor (CMOS) biosensor platform comprising of a switch-matrix-based array of 9′216 carbon nanotube field-effect transistors (CNTFETs) and associated readout circuitry. The switch-matrix allows for flexible selection and simultaneous routing of 96 sensor elements to the corresponding readout channels. A low-noise, wide-bandwidth, wide-dynamic-range transimpedance continuous-time amplifier architecture has been implemented to facilitate resistance measurements in the range between 50 kΩ and 1 GΩ at a bandwidth of up to 1 MHz. The achieved accuracy of the resistance measurements over the whole range is 4%. The system has been successfully fabricated and tested and shows a noise performance equal to 2.14 pArms at a bandwidth of 1 kHz and 0.84 nArms at a bandwidth of 1 MHz. A batch integration of the CNTFETs has been achieved by using a dielectrophoresis (DEP)–based manipulation technique. The current-voltage curves of CNTFETs have been acquired, and the sensing capabilities of the system have been demonstrated by recording resistance changes of CNTFETs upon exposure to solutions with different pH values and different concentrations of NaCl. The smallest resolvable concentrations for the respective analytes were estimated to amount to 0.025 pH-units and 4 mM NaCl. Close https://www.sciencedirect.com/science/article/pii/S0925400518317672?via%3Dihub doi:10.1016/j.snb.2018.10.004 Close
	Shadmani, Amir; Viswam, Vijay; Chen, Yihui; Bounik, Raziyeh; Dragas, Jelena; Radivojevic, Milos; Geissler, Sydney; Sitnikov, Sergey; Muller, Jan; Hierlemann, Andreas Stimulation and Artifact-suppression Techniques for in-vitro High-density Microelectrode Array Systems. Journal Article IEEE Transactions on Biomedical Engineering, 2019. Abstract \| Links \| BibTeX \| タグ: ETH-CMOS-MEA @article{Shadmani2019b, title = {Stimulation and Artifact-suppression Techniques for in-vitro High-density Microelectrode Array Systems.}, author = {Amir Shadmani and Vijay Viswam and Yihui Chen and Raziyeh Bounik and Jelena Dragas and Milos Radivojevic and Sydney Geissler and Sergey Sitnikov and Jan Muller and Andreas Hierlemann }, url = {https://ieeexplore.ieee.org/document/8599003}, doi = {10.1109/TBME.2018.2890530}, year = {2019}, date = {2019-01-01}, journal = {IEEE Transactions on Biomedical Engineering}, abstract = {We present novel voltage stimulation buffers with controlled output current, along with recording circuits featuring adjustable high-pass cut-off filtering to perform efficient stimulation while actively suppressing stimulation artifacts in high-density microelectrode arrays. Owing to the dense packing and close proximity of the electrodes in such systems, a stimulation through one electrode can cause large electrical artifacts on neighboring electrodes that easily saturate the corresponding recording amplifiers. To suppress such artifacts, the high-pass corner frequencies of all available 2048 recording channels can be raised from several Hz to several kHz by applying a "soft-reset" or pole-shifting technique. With the implemented artifact suppression technique, the saturation time of the recording circuits, connected to electrodes in immediate vicinity to the stimulation site, could be reduced to less than 150μs. For the stimulation buffer, we developed a circuit, which can operate in two modes: either control of only the stimulation voltage, or control of current and voltage during stimulation. The voltage-only controlled mode employs a local common-mode feedback operational transconductance amplifier with a near rail-to-rail input/output range, suitable for driving high capacitive loads. The current/voltage controlled mode is based on a positive current conveyor generating adjustable output currents, while its upper and lower output voltages are limited by two feedback loops. The current/voltage controlled circuit can generate stimulation pulses up to 30 μA with less than ±0.1% linearity error in the low-current mode, and up to 300 μA with less than ±0.2% linearity error in the high-current mode.}, keywords = {ETH-CMOS-MEA}, pubstate = {published}, tppubtype = {article} } Close We present novel voltage stimulation buffers with controlled output current, along with recording circuits featuring adjustable high-pass cut-off filtering to perform efficient stimulation while actively suppressing stimulation artifacts in high-density microelectrode arrays. Owing to the dense packing and close proximity of the electrodes in such systems, a stimulation through one electrode can cause large electrical artifacts on neighboring electrodes that easily saturate the corresponding recording amplifiers. To suppress such artifacts, the high-pass corner frequencies of all available 2048 recording channels can be raised from several Hz to several kHz by applying a "soft-reset" or pole-shifting technique. With the implemented artifact suppression technique, the saturation time of the recording circuits, connected to electrodes in immediate vicinity to the stimulation site, could be reduced to less than 150μs. For the stimulation buffer, we developed a circuit, which can operate in two modes: either control of only the stimulation voltage, or control of current and voltage during stimulation. The voltage-only controlled mode employs a local common-mode feedback operational transconductance amplifier with a near rail-to-rail input/output range, suitable for driving high capacitive loads. The current/voltage controlled mode is based on a positive current conveyor generating adjustable output currents, while its upper and lower output voltages are limited by two feedback loops. The current/voltage controlled circuit can generate stimulation pulses up to 30 μA with less than ±0.1% linearity error in the low-current mode, and up to 300 μA with less than ±0.2% linearity error in the high-current mode. Close https://ieeexplore.ieee.org/document/8599003 doi:10.1109/TBME.2018.2890530 Close
2018
	Bakkum, Douglas J; Obien, Marie Engelene J; Radivojevic, Milos; Jäckel, David; Frey, Urs; Takahashi, Hirokazu; Hierlemann, Andreas The Axon Initial Segment is the Dominant Contributor to the Neuron's Extracellular Electrical Potential Landscape Journal Article Advanced Biosystems, 2018. Abstract \| Links \| BibTeX \| タグ: ETH-CMOS-MEA @article{Bakkum2018b, title = {The Axon Initial Segment is the Dominant Contributor to the Neuron's Extracellular Electrical Potential Landscape}, author = {Douglas J. Bakkum and Marie Engelene J. Obien and Milos Radivojevic and David Jäckel and Urs Frey and Hirokazu Takahashi and Andreas Hierlemann}, url = {https://onlinelibrary.wiley.com/doi/full/10.1002/adbi.201800308}, doi = {10.1002/adbi.201800308}, year = {2018}, date = {2018-11-29}, journal = {Advanced Biosystems}, abstract = {Extracellular voltage fields, produced by a neuron's action potentials, provide a widely used means for studying neuronal and neuronal‐network function. The neuron's soma and dendrites are thought to drive the extracellular action potential (EAP) landscape, while the axon's contribution is usually considered less important. However, by recording voltages of single neurons in dissociated rat cortical cultures and Purkinje cells in acute mouse cerebellar slices through hundreds of densely packed electrodes, it is found, instead, that the axon initial segment dominates the measured EAP landscape, and, surprisingly, the soma only contributes to a minor extent. As expected, the recorded dominant signal has negative polarity (charge entering the cell) and initiates at the distal end. Interestingly, signals with positive polarity (charge exiting the cell) occur near some but not all dendritic branches and occur after a delay. Such basic knowledge about which neuronal compartments contribute to the extracellular voltage landscape is important for interpreting results from all electrical readout schemes. Finally, initiation of the electrical activity at the distal end of the axon initial segment (AIS) and subsequent spreading into the axon proper and backward through the proximal AIS toward the soma are confirmed. The corresponding extracellular waveforms across different neuronal compartments could be tracked.}, keywords = {ETH-CMOS-MEA}, pubstate = {published}, tppubtype = {article} } Close Extracellular voltage fields, produced by a neuron's action potentials, provide a widely used means for studying neuronal and neuronal‐network function. The neuron's soma and dendrites are thought to drive the extracellular action potential (EAP) landscape, while the axon's contribution is usually considered less important. However, by recording voltages of single neurons in dissociated rat cortical cultures and Purkinje cells in acute mouse cerebellar slices through hundreds of densely packed electrodes, it is found, instead, that the axon initial segment dominates the measured EAP landscape, and, surprisingly, the soma only contributes to a minor extent. As expected, the recorded dominant signal has negative polarity (charge entering the cell) and initiates at the distal end. Interestingly, signals with positive polarity (charge exiting the cell) occur near some but not all dendritic branches and occur after a delay. Such basic knowledge about which neuronal compartments contribute to the extracellular voltage landscape is important for interpreting results from all electrical readout schemes. Finally, initiation of the electrical activity at the distal end of the axon initial segment (AIS) and subsequent spreading into the axon proper and backward through the proximal AIS toward the soma are confirmed. The corresponding extracellular waveforms across different neuronal compartments could be tracked. Close https://onlinelibrary.wiley.com/doi/full/10.1002/adbi.201800308 doi:10.1002/adbi.201800308 Close
	Viswam, Vijay; Bounik, Raziyeh; Shadmani, Amir; Dragas, Jelena; Urwyler, Cedar; Boos, Julia Alicia; Obien, Marie Engelene J; Muller, Jan; Chen, Yihui; Hierlemann, Andreas Impedance Spectroscopy and Electrophysiological Imaging of Cells With a High-Density CMOS Microelectrode Array System Journal Article IEEE Transactions on Biomedical Circuits and Systems, 12 (6), pp. 1356-1368, 2018, ISSN: 1932-4545. Abstract \| Links \| BibTeX \| タグ: HD-MEA @article{Viswam2018, title = {Impedance Spectroscopy and Electrophysiological Imaging of Cells With a High-Density CMOS Microelectrode Array System}, author = {Vijay Viswam and Raziyeh Bounik and Amir Shadmani and Jelena Dragas and Cedar Urwyler and Julia Alicia Boos and Marie Engelene J. Obien and Jan Muller and Yihui Chen and Andreas Hierlemann}, url = {https://ieeexplore.ieee.org/document/8532304}, doi = {10.1109/TBCAS.2018.2881044}, issn = {1932-4545}, year = {2018}, date = {2018-11-12}, journal = {IEEE Transactions on Biomedical Circuits and Systems}, volume = {12}, number = {6}, pages = {1356-1368}, abstract = {A monolithic multi-functional CMOS microelectrode array system was developed that enables label-free electrochemical impedance spectroscopy of cells in vitro at high spatiotemporal resolution. The electrode array includes 59,760 platinum microelectrodes, densely packed within a 4.5 mm × 2.5 mm sensing region at a pitch of 13.5 μm. A total of 32 on-chip lock-in amplifiers can be used to measure the impedance of any arbitrarily chosen subset of electrodes in the array. A sinusoidal voltage, generated by an on-chip waveform generator with a frequency range from 1 Hz to 1 MHz, was applied to the reference electrode. The sensing currents through the selected recording electrodes were amplified, demodulated, filtered, and digitized to obtain the magnitude and phase information of the respective impedances. The circuitry consumes only 412 μW at 3.3 V supply voltage and occupies only 0.1 mm 2 , for each channel. The system also included 2048 extracellular action-potential recording channels on the same chip. Proof of concept measurements of electrical impedance imaging and electrophysiology recording of cardiac cells and brain slices are demonstrated in this paper. Optical and impedance images showed a strong correlation.}, keywords = {HD-MEA}, pubstate = {published}, tppubtype = {article} } Close A monolithic multi-functional CMOS microelectrode array system was developed that enables label-free electrochemical impedance spectroscopy of cells in vitro at high spatiotemporal resolution. The electrode array includes 59,760 platinum microelectrodes, densely packed within a 4.5 mm × 2.5 mm sensing region at a pitch of 13.5 μm. A total of 32 on-chip lock-in amplifiers can be used to measure the impedance of any arbitrarily chosen subset of electrodes in the array. A sinusoidal voltage, generated by an on-chip waveform generator with a frequency range from 1 Hz to 1 MHz, was applied to the reference electrode. The sensing currents through the selected recording electrodes were amplified, demodulated, filtered, and digitized to obtain the magnitude and phase information of the respective impedances. The circuitry consumes only 412 μW at 3.3 V supply voltage and occupies only 0.1 mm 2 , for each channel. The system also included 2048 extracellular action-potential recording channels on the same chip. Proof of concept measurements of electrical impedance imaging and electrophysiology recording of cardiac cells and brain slices are demonstrated in this paper. Optical and impedance images showed a strong correlation. Close https://ieeexplore.ieee.org/document/8532304 doi:10.1109/TBCAS.2018.2881044 Close
	Lewandowska, Marta K; Bogatikov, Evgenii; Hierlemann, Andreas; Punga, Anna Rostedt Long-term high-density extracellular recordings enable studies of muscle cell physiology and pathology Conference Contribution 700.13 , Society for Neuroscience (SfN) Meeting San Diego, CA, USA, 2018. Abstract \| Links \| BibTeX \| タグ: ETH-CMOS-MEA, Physiology @conference{Lewandowska2018c, title = {Long-term high-density extracellular recordings enable studies of muscle cell physiology and pathology}, author = {Marta K. Lewandowska and Evgenii Bogatikov and Andreas Hierlemann and Anna Rostedt Punga}, url = {https://abstractsonline.com/pp8/#!/4649/presentation/24936}, year = {2018}, date = {2018-11-07}, volume = {Contribution 700.13}, address = {San Diego, CA, USA}, organization = {Society for Neuroscience (SfN) Meeting}, abstract = {Skeletal (voluntary) muscle is the most abundant tissue in the body, thus making it an important biomedical research subject. Studies of neuromuscular transmission, including disorders of defective ion channels or receptors in autoimmune or genetic neuromuscular disorders, require high spatial resolution and an ability to acquire repeated recordings over time in order to track pharmacological interventions. Preclinical techniques for studying diseases of neuromuscular transmission can be enhanced by physiologic ex vivo models of tissue-tissue and cell-cell interactions. We present a method, which we used to follow the development of primary skeletal muscle cells from myoblasts into mature contracting myofibers over more than two months. In contrast to most previous studies, the muscles do not detach from the surface but instead form functional networks between the myofibers, whose electrical signals we observed over the entire culturing period. Primary cultures of mouse myoblasts differentiated into contracting myofibers on a chip that contains an array of 26,400 platinum electrodes at a density of 3,265 electrodes per mm2. Our ability to track extracellular action potentials at subcellular resolution enables discovery of the origin of possible failure mechanisms in muscle diseases. This system in turn enables creation of a novel electrophysiological platform for establishing ex vivo disease models.}, keywords = {ETH-CMOS-MEA, Physiology}, pubstate = {published}, tppubtype = {conference} } Close Skeletal (voluntary) muscle is the most abundant tissue in the body, thus making it an important biomedical research subject. Studies of neuromuscular transmission, including disorders of defective ion channels or receptors in autoimmune or genetic neuromuscular disorders, require high spatial resolution and an ability to acquire repeated recordings over time in order to track pharmacological interventions. Preclinical techniques for studying diseases of neuromuscular transmission can be enhanced by physiologic ex vivo models of tissue-tissue and cell-cell interactions. We present a method, which we used to follow the development of primary skeletal muscle cells from myoblasts into mature contracting myofibers over more than two months. In contrast to most previous studies, the muscles do not detach from the surface but instead form functional networks between the myofibers, whose electrical signals we observed over the entire culturing period. Primary cultures of mouse myoblasts differentiated into contracting myofibers on a chip that contains an array of 26,400 platinum electrodes at a density of 3,265 electrodes per mm2. Our ability to track extracellular action potentials at subcellular resolution enables discovery of the origin of possible failure mechanisms in muscle diseases. This system in turn enables creation of a novel electrophysiological platform for establishing ex vivo disease models. Close https://abstractsonline.com/pp8/#!/4649/presentation/24936 Close
	Fiscella, Michele; Leary, Noelle; Ronchi, Silvia; Hierlemann, Andreas Electrophysiological phenotype characterization of human iPSC-derived dopaminergic neuronal lines by means of high-resolution microelectrode array Conference Contribution 700.13 , Society for Neuroscience (SfN) Meeting San Diego, CA, USA, 2018. Abstract \| Links \| BibTeX \| タグ: HD-MEA, IPSC @conference{Fiscella2018, title = {Electrophysiological phenotype characterization of human iPSC-derived dopaminergic neuronal lines by means of high-resolution microelectrode array}, author = {Michele Fiscella and Noelle Leary and Silvia Ronchi and Andreas Hierlemann }, url = {https://www.abstractsonline.com/pp8/#!/4649/presentation/24924}, year = {2018}, date = {2018-11-07}, volume = {Contribution 700.13}, address = {San Diego, CA, USA}, organization = {Society for Neuroscience (SfN) Meeting}, abstract = {High-resolution-microelectrode-array (HD-MEA) technology enables to study neuronal dynamics at different scales, ranging from axonal physiology to network connectivity [1]. We have used this HD-MEA technology to characterize and compare the electrical phenotypes of commercially available human dopaminergic neurons (iCell DopaNeurons, MyCell DopaNeurons A53T α-synuclein, Cellular Dynamics International, Madison, WI, US). Furthermore, we have studied the effect of human astrocytes (iCell Astrocytes, Cellular Dynamics International, Madison, WI, US) on neural-culture development. Astrocyte/neuron co-cultures showed higher signal amplitudes and higher firing rates than neural cultures without astrocytes. Adding astrocytes to neural cultures changed the whole culture morphology by promoting cell clustering. Interestingly, astrocyte/neuron co-cultures showed a lower sample-to-sample variability across multiple HD-MEA recordings compared to neural cultures without astrocytes. We compared action potential propagation velocities along axons between dopaminergic A53T α-synuclein neurons and the wild-type isogenic control cell line. We found that in both, wild-type and disease-model neurons, axonal action potential propagation velocities were lower than in rat primary cortical neurons [2]. Furthermore, we found different axonal-action-potential-velocity-development profiles of A53T α-synuclein dopaminergic neurons and the wild-type counterpart. Finally, we were able to precisely evoke action potentials in individual single human neurons by subcellular-resolution electrical stimulation. HD-MEA systems enable to access novel electrophysiological parameters of iPSC-derived neurons, which can be potentially used as biomarkers for phenotype screening and drug testing.}, keywords = {HD-MEA, IPSC}, pubstate = {published}, tppubtype = {conference} } Close High-resolution-microelectrode-array (HD-MEA) technology enables to study neuronal dynamics at different scales, ranging from axonal physiology to network connectivity [1]. We have used this HD-MEA technology to characterize and compare the electrical phenotypes of commercially available human dopaminergic neurons (iCell DopaNeurons, MyCell DopaNeurons A53T α-synuclein, Cellular Dynamics International, Madison, WI, US). Furthermore, we have studied the effect of human astrocytes (iCell Astrocytes, Cellular Dynamics International, Madison, WI, US) on neural-culture development. Astrocyte/neuron co-cultures showed higher signal amplitudes and higher firing rates than neural cultures without astrocytes. Adding astrocytes to neural cultures changed the whole culture morphology by promoting cell clustering. Interestingly, astrocyte/neuron co-cultures showed a lower sample-to-sample variability across multiple HD-MEA recordings compared to neural cultures without astrocytes. We compared action potential propagation velocities along axons between dopaminergic A53T α-synuclein neurons and the wild-type isogenic control cell line. We found that in both, wild-type and disease-model neurons, axonal action potential propagation velocities were lower than in rat primary cortical neurons [2]. Furthermore, we found different axonal-action-potential-velocity-development profiles of A53T α-synuclein dopaminergic neurons and the wild-type counterpart. Finally, we were able to precisely evoke action potentials in individual single human neurons by subcellular-resolution electrical stimulation. HD-MEA systems enable to access novel electrophysiological parameters of iPSC-derived neurons, which can be potentially used as biomarkers for phenotype screening and drug testing. Close https://www.abstractsonline.com/pp8/#!/4649/presentation/24924 Close
	Emmenegger, Vishalini; Bartram, Julian; Sitnikov, Sergey; Hierlemann, Andreas Investigating the analog modulation of action-potential waveforms in axonal arbors of cortical neurons using whole-cell patch-clamp recordings and high-density microelectrode arrays Conference Contribution 203.05 , Society for Neuroscience (SfN) Meeting, San Diego, CA, USA, 2018. Abstract \| Links \| BibTeX \| タグ: ETH-CMOS-MEA @conference{Emmenegger2018, title = {Investigating the analog modulation of action-potential waveforms in axonal arbors of cortical neurons using whole-cell patch-clamp recordings and high-density microelectrode arrays}, author = {Vishalini Emmenegger and Julian Bartram and Sergey Sitnikov and Andreas Hierlemann}, url = {https://abstractsonline.com/pp8/#!/4649/presentation/9323}, year = {2018}, date = {2018-11-04}, volume = {Contribution 203.05}, publisher = {Society for Neuroscience (SfN) Meeting}, address = {San Diego, CA, USA}, abstract = {Analog-digital facilitation (ADF) is a type of short-term plasticity, where the subthreshold membrane potential in the presynaptic element enhances the spike-evoked synaptic response. Most cases of ADF have been induced by long (0.3-10 s) subthreshold depolarization of the soma, while in few cases, transient (15-200 ms) hyperpolarization has been evoked immediately before the action potential (AP). In both cases, somatic membrane fluctuations modulate the biophysical properties of voltage-gated ion channels causing changes in the AP waveform, which result in larger release of neurotransmitters. However, it is still unknown, whether the modulation of the AP waveform changes with increasing distance from the soma and differs in different axonal arbors, and whether such modulation affects the velocity of AP propagation. Here, we used CMOS-based high-density microelectrode arrays (HD-MEA) with 26,400 microelectrodes, which enabled unprecedented high-resolution access to investigating axonal signaling at multiple sites simultaneously, thus providing in-depth information on the propagation of AP. The subthreshold depolarization and hyperpolarization of the presynaptic cell was performed using whole-cell patch-clamp recordings from cells in low-density cortical cultures, plated on a HD-MEA that allowed to trace the effects of such manipulations on AP propagation characteristics. Array-wide spike-triggered average signals were computed, and their spatiotemporal distribution was reconstructed. In order to study the changes in extracellular AP waveforms, we first induced pharmacological modulations using dendrotoxin and carbamazepine, which increased AP width and amplitude. As a next step, we evoked AP broadening and amplitude changes by subthreshold depolarization and hyperpolarization. We detected the extracellular AP waveforms directly under the soma and traced them throughout the axon during various time spans and for different holding potentials. We found that changes in AP propagation velocity were correlated to the detected AP broadening. Our preliminary data evidenced changes in AP waveforms with increasing distance from the soma along the axon, but further experiments on synaptically coupled neurons using paired recordings will be performed to better understand the influence of AP modulation on ADF. Information encoding in neuronal circuits is probably contingent on both, temporal spike patterns and spike waveforms. In the light of the latter being typically disregarded in computational models, the study of the analog modulation of AP waveforms will contribute to a better understanding of neuronal information processing.}, keywords = {ETH-CMOS-MEA}, pubstate = {published}, tppubtype = {conference} } Close Analog-digital facilitation (ADF) is a type of short-term plasticity, where the subthreshold membrane potential in the presynaptic element enhances the spike-evoked synaptic response. Most cases of ADF have been induced by long (0.3-10 s) subthreshold depolarization of the soma, while in few cases, transient (15-200 ms) hyperpolarization has been evoked immediately before the action potential (AP). In both cases, somatic membrane fluctuations modulate the biophysical properties of voltage-gated ion channels causing changes in the AP waveform, which result in larger release of neurotransmitters. However, it is still unknown, whether the modulation of the AP waveform changes with increasing distance from the soma and differs in different axonal arbors, and whether such modulation affects the velocity of AP propagation. Here, we used CMOS-based high-density microelectrode arrays (HD-MEA) with 26,400 microelectrodes, which enabled unprecedented high-resolution access to investigating axonal signaling at multiple sites simultaneously, thus providing in-depth information on the propagation of AP. The subthreshold depolarization and hyperpolarization of the presynaptic cell was performed using whole-cell patch-clamp recordings from cells in low-density cortical cultures, plated on a HD-MEA that allowed to trace the effects of such manipulations on AP propagation characteristics. Array-wide spike-triggered average signals were computed, and their spatiotemporal distribution was reconstructed. In order to study the changes in extracellular AP waveforms, we first induced pharmacological modulations using dendrotoxin and carbamazepine, which increased AP width and amplitude. As a next step, we evoked AP broadening and amplitude changes by subthreshold depolarization and hyperpolarization. We detected the extracellular AP waveforms directly under the soma and traced them throughout the axon during various time spans and for different holding potentials. We found that changes in AP propagation velocity were correlated to the detected AP broadening. Our preliminary data evidenced changes in AP waveforms with increasing distance from the soma along the axon, but further experiments on synaptically coupled neurons using paired recordings will be performed to better understand the influence of AP modulation on ADF. Information encoding in neuronal circuits is probably contingent on both, temporal spike patterns and spike waveforms. In the light of the latter being typically disregarded in computational models, the study of the analog modulation of AP waveforms will contribute to a better understanding of neuronal information processing. Close https://abstractsonline.com/pp8/#!/4649/presentation/9323 Close
	Ronchi, Silvia; Fiscella, Michele; Marchetti, Camilla; Viswam, Vijay; Müller, Jan; Frey, Urs; Hierlemann, Andreas Single-neuron sub-cellular-resolution electrical stimulation with high-density microelectrode arrays Conference Contribution 174.05 , Society for Neuroscience (SfN) Meeting San Diego, CA, USA, 2018. Abstract \| Links \| BibTeX \| タグ: ETH-CMOS-MEA, Stimulation @conference{Ronchi2018, title = {Single-neuron sub-cellular-resolution electrical stimulation with high-density microelectrode arrays}, author = {Silvia Ronchi and Michele Fiscella and Camilla Marchetti and Vijay Viswam and Jan Müller and Urs Frey and Andreas Hierlemann}, url = {https://abstractsonline.com/pp8/#!/4649/presentation/24382}, year = {2018}, date = {2018-11-04}, volume = {Contribution 174.05}, address = {San Diego, CA, USA}, organization = {Society for Neuroscience (SfN) Meeting}, abstract = {Non-invasive electrical stimulation is a consolidated technique to study and control neural activity in the brain and peripheral nervous system. It is used, e.g., for controlling Parkinson's disease or to induce sensation in paralyzed patients (Armenta Salas et al., 2018), as well as for attempts to restore vision (Fan et al., 2018; Grosberg et al., 2017) and hearing (Wilson & Dorman, 2008). A common requirement in electrical stimulation is the precise and controlled stimulation of individual targeted neurons. For achieving this purpose, it is necessary that electrodes can stimulate and record extracellular signals at sub-cellular resolution. Furthermore, it is important to design efficient stimulation pulses to be delivered to the neurons. In the present work we used an CMOS-based high-density microelectrode array (HD-MEA) (Ballini et al., 2014), featuring 26’400 bidirectional electrodes with a pitch of 17.5 µm, which was designed for in-vitro applications. This high-resolution was used to test electrical stimulation parameters in vitro, which then could potentially be adapted to elicit single-cell action potentials in vivo. In this work we used different stimulation parameters, such as waveforms, amplitudes and durations (Grosberg et al., 2017; Wagenaar, Pine, & Potter, 2004), using 5x9 µm² electrodes to target sub-cellular structures in single neurons. E-18 Wistar rat cortical neurons were stimulated at days-in-vitro 10, 15, 20 and 25 using randomized voltage and current stimulation modalities. Axon initial segments of individual neurons (Radivojevic et al., 2016) were targeted for stimulation, enabled by the HD-MEA device. We found that voltage biphasic anodic-cathodic waveforms were less efficient than biphasic cathodic-anodic waveforms in eliciting action potentials in a single neuron. Moreover, it was possible to detect action potentials directly at the cell soma, which ensured a reliable confirmation of successful neuron stimulation. Finally, HD-MEA technology enabled to elicit action potentials in single-neurons embedded in high-density cell cultures. The obtained results can be used to optimize in vivo single-cell targeting for stimulation and read-out.}, keywords = {ETH-CMOS-MEA, Stimulation}, pubstate = {published}, tppubtype = {conference} } Close Non-invasive electrical stimulation is a consolidated technique to study and control neural activity in the brain and peripheral nervous system. It is used, e.g., for controlling Parkinson's disease or to induce sensation in paralyzed patients (Armenta Salas et al., 2018), as well as for attempts to restore vision (Fan et al., 2018; Grosberg et al., 2017) and hearing (Wilson & Dorman, 2008). A common requirement in electrical stimulation is the precise and controlled stimulation of individual targeted neurons. For achieving this purpose, it is necessary that electrodes can stimulate and record extracellular signals at sub-cellular resolution. Furthermore, it is important to design efficient stimulation pulses to be delivered to the neurons. In the present work we used an CMOS-based high-density microelectrode array (HD-MEA) (Ballini et al., 2014), featuring 26’400 bidirectional electrodes with a pitch of 17.5 µm, which was designed for in-vitro applications. This high-resolution was used to test electrical stimulation parameters in vitro, which then could potentially be adapted to elicit single-cell action potentials in vivo. In this work we used different stimulation parameters, such as waveforms, amplitudes and durations (Grosberg et al., 2017; Wagenaar, Pine, & Potter, 2004), using 5x9 µm² electrodes to target sub-cellular structures in single neurons. E-18 Wistar rat cortical neurons were stimulated at days-in-vitro 10, 15, 20 and 25 using randomized voltage and current stimulation modalities. Axon initial segments of individual neurons (Radivojevic et al., 2016) were targeted for stimulation, enabled by the HD-MEA device. We found that voltage biphasic anodic-cathodic waveforms were less efficient than biphasic cathodic-anodic waveforms in eliciting action potentials in a single neuron. Moreover, it was possible to detect action potentials directly at the cell soma, which ensured a reliable confirmation of successful neuron stimulation. Finally, HD-MEA technology enabled to elicit action potentials in single-neurons embedded in high-density cell cultures. The obtained results can be used to optimize in vivo single-cell targeting for stimulation and read-out. Close https://abstractsonline.com/pp8/#!/4649/presentation/24382 Close
	Bartram, Julian; Schroter, Manuel; Ronchi, Silvia; Emmenegger, Vishalini; Muller, Jan; Hierlemann, Andreas Mechanisms of homeostatic synaptic plasticity Conference Contribution 037.11 , Society for Neuroscience (SfN) Meeting San Diego, CA, USA, 2018. Abstract \| Links \| BibTeX \| タグ: HD-MEA @conference{Bartram2018, title = {Mechanisms of homeostatic synaptic plasticity}, author = {Julian Bartram and Manuel Schroter and Silvia Ronchi and Vishalini Emmenegger and Jan Muller and Andreas Hierlemann}, url = {https://www.abstractsonline.com/pp8/#!/4649/presentation/3968}, year = {2018}, date = {2018-11-03}, volume = {Contribution 037.11}, address = {San Diego, CA, USA}, organization = {Society for Neuroscience (SfN) Meeting}, abstract = {Homeostatic plasticity is a crucial set of mechanisms acting at typically slow temporal scales in order to stabilize neuronal spike rates. Despite the functional significance of such processes, revealing the precise induction mechanisms has proven to be difficult, as the roles of postsynaptic spiking and synaptic activity are still debated. For a clearer picture of the induction process to emerge, information about synaptic efficacies of multiple inputs needs to be combined with accurate information about spiking activities of the respective presynaptic cells and the postsynaptic cell during the induction of homeostatic plasticity. In this study, we were able to achieve such measurements by performing combined high-density microelectrode array (HD-MEA) and whole-cell patch-clamp recordings in cultures of primary cortical neurons. Homeostatic plasticity was induced by pharmacological alteration of global network spiking and synaptic transmission with TTX or CNQX. Monosynaptic connections between neurons - here with a focus on excitatory connections between pyramidal cells - were identified by correlating presynaptic spiking activity (HD-MEA recordings) with postsynaptic subthreshold responses (patch current-clamp recordings). Presynaptic spiking was spontaneously observed or could be induced via the stimulation capabilities of the HD-MEA system. This experimental approach enabled us to link changes in synaptic efficacy with the respective pre- and postsynaptic spike patterns, recorded during the induction phase, which sheds new light on the rules and mechanisms of homeostatic synaptic plasticity at excitatory synapses. Financial support through the ERC Advanced Grant 694829 “neuroXscales” is gratefully acknowledged.}, keywords = {HD-MEA}, pubstate = {published}, tppubtype = {conference} } Close Homeostatic plasticity is a crucial set of mechanisms acting at typically slow temporal scales in order to stabilize neuronal spike rates. Despite the functional significance of such processes, revealing the precise induction mechanisms has proven to be difficult, as the roles of postsynaptic spiking and synaptic activity are still debated. For a clearer picture of the induction process to emerge, information about synaptic efficacies of multiple inputs needs to be combined with accurate information about spiking activities of the respective presynaptic cells and the postsynaptic cell during the induction of homeostatic plasticity. In this study, we were able to achieve such measurements by performing combined high-density microelectrode array (HD-MEA) and whole-cell patch-clamp recordings in cultures of primary cortical neurons. Homeostatic plasticity was induced by pharmacological alteration of global network spiking and synaptic transmission with TTX or CNQX. Monosynaptic connections between neurons - here with a focus on excitatory connections between pyramidal cells - were identified by correlating presynaptic spiking activity (HD-MEA recordings) with postsynaptic subthreshold responses (patch current-clamp recordings). Presynaptic spiking was spontaneously observed or could be induced via the stimulation capabilities of the HD-MEA system. This experimental approach enabled us to link changes in synaptic efficacy with the respective pre- and postsynaptic spike patterns, recorded during the induction phase, which sheds new light on the rules and mechanisms of homeostatic synaptic plasticity at excitatory synapses. Financial support through the ERC Advanced Grant 694829 “neuroXscales” is gratefully acknowledged. Close https://www.abstractsonline.com/pp8/#!/4649/presentation/3968 Close
	Yuan, Xinyue; Emmenegger, Vishalini; Obien, Marie Engelene J; Hierlemann, Andreas; Frey, Urs Dual-Mode Microelectrode Array Featuring 20k Electrodes and High SNR for Extracellular Recording of Neural Networks Conference paper 6065 , IEEE Biomedical Circuits and Systems Conference (BioCAS) Cleveland, Ohio, USA, 2018. Abstract \| Links \| BibTeX \| タグ: ETH-CMOS-MEA @conference{Yuan2018b, title = {Dual-Mode Microelectrode Array Featuring 20k Electrodes and High SNR for Extracellular Recording of Neural Networks}, author = {Xinyue Yuan and Vishalini Emmenegger and Marie Engelene J. Obien and Andreas Hierlemann and Urs Frey}, url = {https://www.epapers.org/biocas2018/ESR/paper_details.php?PHPSESSID=ok076vdjtkiu7kett65d8hk0g0&paper_id=6056}, year = {2018}, date = {2018-10-17}, volume = {paper 6065}, address = {Cleveland, Ohio, USA}, organization = {IEEE Biomedical Circuits and Systems Conference (BioCAS)}, abstract = {In recent electrophysiological studies, CMOS-based high-density microelectrode arrays (HD-MEA) have been widely used for studies of both in-vitro and in-vivo neuronal signals and network behavior. Yet, an open issue in MEA design concerns the tradeoff between signal-to-noise ratio (SNR) and number of readout channels. Here we present a new HD-MEA design in 0.18 μm CMOS technology, consisting of 19,584 electrodes at a pitch of 18.0 μm. By combing two readout structures,namely active-pixel-sensor (APS) and switch-matrix (SM) on a single chip, the dual-mode HD-MEA is capable of recording simultaneously from the entire array and achieving high signal-to-noise-ratio recordings on a subset of electrodes. The APS readout circuits feature a noise level of 10.9 μVrms for the action potential band (300 Hz - 5 kHz), while the noise level for the switch-matrix readout is 3.1 μVrms. }, keywords = {ETH-CMOS-MEA}, pubstate = {published}, tppubtype = {conference} } Close In recent electrophysiological studies, CMOS-based high-density microelectrode arrays (HD-MEA) have been widely used for studies of both in-vitro and in-vivo neuronal signals and network behavior. Yet, an open issue in MEA design concerns the tradeoff between signal-to-noise ratio (SNR) and number of readout channels. Here we present a new HD-MEA design in 0.18 μm CMOS technology, consisting of 19,584 electrodes at a pitch of 18.0 μm. By combing two readout structures,namely active-pixel-sensor (APS) and switch-matrix (SM) on a single chip, the dual-mode HD-MEA is capable of recording simultaneously from the entire array and achieving high signal-to-noise-ratio recordings on a subset of electrodes. The APS readout circuits feature a noise level of 10.9 μVrms for the action potential band (300 Hz - 5 kHz), while the noise level for the switch-matrix readout is 3.1 μVrms. Close https://www.epapers.org/biocas2018/ESR/paper_details.php?PHPSESSID=ok076vdjtkiu7[...] Close
	Lewandowska, Marta K; Bogatikov, Evgenii; Hierlemann, Andreas; Punga, Anna Rostedt Long-Term High-Density Extracellular Recordings Enable Studies of Muscle Cell Physiology Journal Article Frontiers in Physiology, 9 , 2018. Abstract \| Links \| BibTeX \| タグ: ETH-CMOS-MEA, Muscle @article{Lewandowska2018cb, title = {Long-Term High-Density Extracellular Recordings Enable Studies of Muscle Cell Physiology }, author = {Marta K. Lewandowska and Evgenii Bogatikov and Andreas Hierlemann and Anna Rostedt Punga}, url = {https://www.frontiersin.org/article/10.3389/fphys.2018.01424 }, doi = {10.3389/fphys.2018.01424}, year = {2018}, date = {2018-10-09}, journal = {Frontiers in Physiology}, volume = {9}, abstract = {Skeletal (voluntary) muscle is the most abundant tissue in the body, thus making it an important biomedical research subject. Studies of neuromuscular transmission, including disorders of ion channels or receptors in autoimmune or genetic neuromuscular disorders, require high-spatial-resolution measurement techniques and an ability to acquire repeated recordings over time in order to track pharmacological interventions. Preclinical techniques for studying diseases of neuromuscular transmission can be enhanced by physiologic ex vivo models of tissue-tissue and cell-cell interactions. Here, we present a method, which allows tracking the development of primary skeletal muscle cells from myoblasts into mature contracting myotubes over more than 2 months. In contrast to most previous studies, the myotubes did not detach from the surface but instead formed functional networks between the myotubes, whose electrical signals were observed over the entire culturing period. Primary cultures of mouse myoblasts differentiated into contracting myotubes on a chip that contained an array of 26,400 platinum electrodes at a density of 3,265 electrodes per mm2. Our ability to track extracellular action potentials at subcellular resolution enabled study of skeletal muscle development and kinetics, modes of spiking and spatio-temporal relationships between muscles. The developed system in turn enables creation of a novel electrophysiological platform for establishing ex vivo disease models. }, keywords = {ETH-CMOS-MEA, Muscle}, pubstate = {published}, tppubtype = {article} } Close Skeletal (voluntary) muscle is the most abundant tissue in the body, thus making it an important biomedical research subject. Studies of neuromuscular transmission, including disorders of ion channels or receptors in autoimmune or genetic neuromuscular disorders, require high-spatial-resolution measurement techniques and an ability to acquire repeated recordings over time in order to track pharmacological interventions. Preclinical techniques for studying diseases of neuromuscular transmission can be enhanced by physiologic ex vivo models of tissue-tissue and cell-cell interactions. Here, we present a method, which allows tracking the development of primary skeletal muscle cells from myoblasts into mature contracting myotubes over more than 2 months. In contrast to most previous studies, the myotubes did not detach from the surface but instead formed functional networks between the myotubes, whose electrical signals were observed over the entire culturing period. Primary cultures of mouse myoblasts differentiated into contracting myotubes on a chip that contained an array of 26,400 platinum electrodes at a density of 3,265 electrodes per mm2. Our ability to track extracellular action potentials at subcellular resolution enabled study of skeletal muscle development and kinetics, modes of spiking and spatio-temporal relationships between muscles. The developed system in turn enables creation of a novel electrophysiological platform for establishing ex vivo disease models. Close https://www.frontiersin.org/article/10.3389/fphys.2018.01424 doi:10.3389/fphys.2018.01424 Close
	Diggelmann, Roland; Fiscella, Michele; Hierlemann, Andreas; Franke, Felix Automatic Spike Sorting Algorithm for High-Density Microelectrode Arrays Journal Article Journal of Neurophysiology, 120 (4), 2018. Abstract \| Links \| BibTeX \| タグ: MEA Technology @article{Diggelmann2018, title = {Automatic Spike Sorting Algorithm for High-Density Microelectrode Arrays}, author = {Roland Diggelmann and Michele Fiscella and Andreas Hierlemann and Felix Franke}, url = {https://www.physiology.org/doi/pdf/10.1152/jn.00803.2017}, doi = {10.1152/jn.00803.2017}, year = {2018}, date = {2018-09-12}, journal = {Journal of Neurophysiology}, volume = {120}, number = {4}, abstract = {High-density microelectrode arrays (HD-MEAs) can be used to record extracellular action potentials from hundreds to thousands of neurons simultaneously. Efficient spike-sorters have to be developed to cope with such large data volumes. Most existing spike sorting methods for single electrodes or small multi-electrodes, however, suffer from the "curse of dimensionality", and cannot be directly applied to recordings with hundreds of electrodes. This holds particularly true for the standard reference spike sorting algorithm, principal-component-analysis-based feature extraction, followed by k-means or expectation maximization clustering, against which most spike-sorters are evaluated. We present a spike sorting algorithm that circumvents the dimensionality problem by sorting local groups of electrodes independently using classical spike sorting approaches. It is scalable to any number of recording electrodes and well suited for parallel computing. The combination of data pre-whitening before the principal-component-analysis-based extraction and a parameter-free clustering algorithm obviated the need for parameter adjustments. We evaluated its performance using surrogate data in which we systematically varied spike amplitudes and spike rates and which were generated by inserting template spikes into the voltage traces of real recordings. In a direct comparison, our algorithm could compete with existing state-of-the-art spike sorters in terms of sensitivity and precision, while parameter adjustment or manual cluster curation were not required.}, keywords = {MEA Technology}, pubstate = {published}, tppubtype = {article} } Close High-density microelectrode arrays (HD-MEAs) can be used to record extracellular action potentials from hundreds to thousands of neurons simultaneously. Efficient spike-sorters have to be developed to cope with such large data volumes. Most existing spike sorting methods for single electrodes or small multi-electrodes, however, suffer from the "curse of dimensionality", and cannot be directly applied to recordings with hundreds of electrodes. This holds particularly true for the standard reference spike sorting algorithm, principal-component-analysis-based feature extraction, followed by k-means or expectation maximization clustering, against which most spike-sorters are evaluated. We present a spike sorting algorithm that circumvents the dimensionality problem by sorting local groups of electrodes independently using classical spike sorting approaches. It is scalable to any number of recording electrodes and well suited for parallel computing. The combination of data pre-whitening before the principal-component-analysis-based extraction and a parameter-free clustering algorithm obviated the need for parameter adjustments. We evaluated its performance using surrogate data in which we systematically varied spike amplitudes and spike rates and which were generated by inserting template spikes into the voltage traces of real recordings. In a direct comparison, our algorithm could compete with existing state-of-the-art spike sorters in terms of sensitivity and precision, while parameter adjustment or manual cluster curation were not required. Close https://www.physiology.org/doi/pdf/10.1152/jn.00803.2017 doi:10.1152/jn.00803.2017 Close
	Ronchi, Silvia; Fiscella, Michele; Muller, Jan; Viswam, Vijay; Frey, Urs; Hierlemann, Andreas Single-cell electrical stimulation with CMOS-based high-density microelectrode arrays Conference 11th International Meeting on Substrate Integrated Microelectrode Arrays (MEA Meeting) Reutlingen, Germany, 2018. Abstract \| Links \| BibTeX \| タグ: ETH-CMOS-MEA, Stimulation @conference{Ronchi2018b, title = {Single-cell electrical stimulation with CMOS-based high-density microelectrode arrays}, author = {Silvia Ronchi and Michele Fiscella and Jan Muller and Vijay Viswam and Urs Frey and Andreas Hierlemann}, url = {https://www.frontiersin.org/10.3389/conf.fncel.2018.38.00086/event_abstract}, doi = {10.3389/conf.fncel.2018.38.00086}, year = {2018}, date = {2018-07-04}, address = {Reutlingen, Germany}, organization = {11th International Meeting on Substrate Integrated Microelectrode Arrays (MEA Meeting)}, abstract = {The main goal of this work was to explore electrical stimulation parameters that reproducibly and precisely elicit action potentials in single neurons (Wagenaar et al. 2004). We compared voltage and current modalities’ and their efficacy in activating single neurons; we also studied the related stimulation artifacts. For our studies, we used a CMOS-based MEA featuring 26400 electrodes at 17.5 µm pitch (Ballini et al. 2014). }, keywords = {ETH-CMOS-MEA, Stimulation}, pubstate = {published}, tppubtype = {conference} } Close The main goal of this work was to explore electrical stimulation parameters that reproducibly and precisely elicit action potentials in single neurons (Wagenaar et al. 2004). We compared voltage and current modalities’ and their efficacy in activating single neurons; we also studied the related stimulation artifacts. For our studies, we used a CMOS-based MEA featuring 26400 electrodes at 17.5 µm pitch (Ballini et al. 2014). Close https://www.frontiersin.org/10.3389/conf.fncel.2018.38.00086/event_abstract doi:10.3389/conf.fncel.2018.38.00086 Close
	Obien, Marie Engelene J; Zorzi, Giulio; Fiscella, Michele; Leary, Noelle; Hierlemann, Andreas Comparison of axonal-conduction velocity in developing primary cells and human iPSC-derived neurons Conference 11th International Meeting on Substrate Integrated Microelectrode Arrays (MEA Meeting) Reutlingen, Germany, 2018. Abstract \| Links \| BibTeX \| タグ: ETH-CMOS-MEA, MaxOne @conference{Obien2018, title = {Comparison of axonal-conduction velocity in developing primary cells and human iPSC-derived neurons}, author = {Marie Engelene J. Obien and Giulio Zorzi and Michele Fiscella and Noelle Leary and Andreas Hierlemann}, url = {https://www.frontiersin.org/10.3389/conf.fncel.2018.38.00095/event_abstract}, doi = {10.3389/conf.fncel.2018.38.00095}, year = {2018}, date = {2018-07-04}, address = {Reutlingen, Germany}, organization = {11th International Meeting on Substrate Integrated Microelectrode Arrays (MEA Meeting)}, abstract = {Neurons communicate through action potentials propagating along axons. In developing cell cultures, axonal arbor outgrowth indicates the formation of synaptic connections between neurons, which form networks. As axons regulate the transfer of information, we hypothesize that axonal conduction characteristics, e.g., axonal action potential amplitude and propagation velocity, may be indicative of the maturation state of cells and the strength of interneuronal connections.}, keywords = {ETH-CMOS-MEA, MaxOne}, pubstate = {published}, tppubtype = {conference} } Close Neurons communicate through action potentials propagating along axons. In developing cell cultures, axonal arbor outgrowth indicates the formation of synaptic connections between neurons, which form networks. As axons regulate the transfer of information, we hypothesize that axonal conduction characteristics, e.g., axonal action potential amplitude and propagation velocity, may be indicative of the maturation state of cells and the strength of interneuronal connections. Close https://www.frontiersin.org/10.3389/conf.fncel.2018.38.00095/event_abstract doi:10.3389/conf.fncel.2018.38.00095 Close
	Zorzi, Giulio; Obien, Marie Engelene J; Fiscella, Michele; Leary, Noelle; Hierlemann, Andreas Automatic extraction of axonal arbor morphology applied to h-iPSC-derived neurons Conference 11th International Meeting on Substrate Integrated Microelectrode Arrays (MEA Meeting) Reutlingen, Germany, 2018. Abstract \| Links \| BibTeX \| タグ: ETH-CMOS-MEA, MaxOne @conference{Zorzi2018, title = {Automatic extraction of axonal arbor morphology applied to h-iPSC-derived neurons}, author = {Giulio Zorzi and Marie Engelene J. Obien and Michele Fiscella and Noelle Leary and Andreas Hierlemann}, url = {https://www.frontiersin.org/10.3389/conf.fncel.2018.38.00049/event_abstract}, doi = {10.3389/conf.fncel.2018.38.00049}, year = {2018}, date = {2018-07-04}, address = {Reutlingen, Germany}, organization = {11th International Meeting on Substrate Integrated Microelectrode Arrays (MEA Meeting)}, abstract = {Neurons derived from human induced pluripotent stem cells (h-iPSCs) offer tremendous opportunities to investigate the mechanisms involved in brain function and to model neurodegenerative diseases. Analyzing the behavior of h-iPSC-derived neurons that represent the phenotypes of human neurological disorders paves the way for the development of physiologically-relevant models and assays for drug discovery. In this framework, we utilize a CMOS-based high-density microelectrode array (HD-MEA, MaxWell Biosystems) to investigate h-iPSC neurons at sub-cellular resolution. Recording extracellular action potentials (EAPs or spikes) of cultured neurons through microelectrode arrays (MEAs) is a well-established technique for extracting valuable features of neuronal function and network connectivity (Obien et al., Frontiers in Neuroscience, 2015). }, keywords = {ETH-CMOS-MEA, MaxOne}, pubstate = {published}, tppubtype = {conference} } Close Neurons derived from human induced pluripotent stem cells (h-iPSCs) offer tremendous opportunities to investigate the mechanisms involved in brain function and to model neurodegenerative diseases. Analyzing the behavior of h-iPSC-derived neurons that represent the phenotypes of human neurological disorders paves the way for the development of physiologically-relevant models and assays for drug discovery. In this framework, we utilize a CMOS-based high-density microelectrode array (HD-MEA, MaxWell Biosystems) to investigate h-iPSC neurons at sub-cellular resolution. Recording extracellular action potentials (EAPs or spikes) of cultured neurons through microelectrode arrays (MEAs) is a well-established technique for extracting valuable features of neuronal function and network connectivity (Obien et al., Frontiers in Neuroscience, 2015). Close https://www.frontiersin.org/10.3389/conf.fncel.2018.38.00049/event_abstract doi:10.3389/conf.fncel.2018.38.00049 Close
	Bounik, Raziyeh; Gusmaroli, Massimiliano; Viswam, Vijay; Modena, Mario M; Hierlemann, Andreas COMSOL modeling of an integrated impedance sensor in a hanging-drop platform Conference 11th International Meeting on Substrate Integrated Microelectrode Arrays (MEA Meeting) Reutlingen, Germany, 2018. Abstract \| Links \| BibTeX \| タグ: ETH-CMOS-MEA, Microtissue @conference{Bounik2018, title = {COMSOL modeling of an integrated impedance sensor in a hanging-drop platform}, author = {Raziyeh Bounik and Massimiliano Gusmaroli and Vijay Viswam and Mario M. Modena and Andreas Hierlemann}, url = {https://www.frontiersin.org/10.3389/conf.fncel.2018.38.00083/event_abstract}, doi = {10.3389/conf.fncel.2018.38.00083}, year = {2018}, date = {2018-07-04}, address = {Reutlingen, Germany}, organization = {11th International Meeting on Substrate Integrated Microelectrode Arrays (MEA Meeting)}, abstract = {Traditional dish-based, two-dimensional cell cultures have limited prediction capability for drug testing, whereas three-dimensional spherical microtissues (spheroids) and organoids much more accurately replicate physiological conditions of cells in the respective tissue [1,2]. Such spheroids can be formed and cultured in microphysiological multi-tissue formats by using the hanging-drop technology as depicted in Fig. 1 [3]. Like most other microfluidic platforms, the hanging-drop platform still requires a microscope for visual inspection and considerable time for doing off-line measurements, as the spheroids/media have to be harvested from the microfluidic device for labeling and chemical analysis. It would be beneficial to have an integrated on-line multi-functional sensor as an additional readout, located directly at the tissue sites in the hanging-drop platform, so that measurements can be performed in situ and without harvesting medium or the tissue and without interrupting the overall culturing process. }, keywords = {ETH-CMOS-MEA, Microtissue}, pubstate = {published}, tppubtype = {conference} } Close Traditional dish-based, two-dimensional cell cultures have limited prediction capability for drug testing, whereas three-dimensional spherical microtissues (spheroids) and organoids much more accurately replicate physiological conditions of cells in the respective tissue [1,2]. Such spheroids can be formed and cultured in microphysiological multi-tissue formats by using the hanging-drop technology as depicted in Fig. 1 [3]. Like most other microfluidic platforms, the hanging-drop platform still requires a microscope for visual inspection and considerable time for doing off-line measurements, as the spheroids/media have to be harvested from the microfluidic device for labeling and chemical analysis. It would be beneficial to have an integrated on-line multi-functional sensor as an additional readout, located directly at the tissue sites in the hanging-drop platform, so that measurements can be performed in situ and without harvesting medium or the tissue and without interrupting the overall culturing process. Close https://www.frontiersin.org/10.3389/conf.fncel.2018.38.00083/event_abstract doi:10.3389/conf.fncel.2018.38.00083 Close
	Yuan, Xinyue; Hierlemann, Andreas; Frey, Urs Dual-mode Microelectrode Array with 20k-electrodes and High SNR for High-Throughput Extracellular Recording and Stimulation Conference 11th International Meeting on Substrate Integrated Microelectrode Arrays (MEA Meeting) Reutlingen, Germany, 2018. Abstract \| Links \| BibTeX \| タグ: ETH-CMOS-MEA, Stimulation @conference{Yuan2018, title = {Dual-mode Microelectrode Array with 20k-electrodes and High SNR for High-Throughput Extracellular Recording and Stimulation}, author = {Xinyue Yuan and Andreas Hierlemann and Urs Frey}, url = {https://https://www.frontiersin.org/Community/AbstractDetails.aspx?ABS_DOI=10.3389/conf.fncel.2018.38.00088&eid=5473&sname=MEA_Meeting_2018_%7C_11th_International_Meeting_on_Substrate_Integrated_Microelectrode_Arrays}, doi = {10.3389/conf.fncel.2018.38.00088}, year = {2018}, date = {2018-07-04}, address = {Reutlingen, Germany}, organization = {11th International Meeting on Substrate Integrated Microelectrode Arrays (MEA Meeting)}, abstract = {Recording and analysis of neuronal signals can provide much insight into how neurons process information and communicate with each other. Recent advancements of microelectrode-array (MEA) technology provide unprecedented means to study neuronal signals and network behavior in in vitro and in vivo applications [1], [2]. The trade-off between noise performance, power consumption and electrode density, however, remains a major challenge in MEA design. To balance this tradeoff, we designed a Dual-mode (DM) MEA that combines two major types of readout schemes, i.e., the active-pixel-sensor (APS) and switch-matrix (SM) schemes, in order to achieve high electrode density and high signal-to-noise ratio (SNR) at the same time. Based on a previous prototype [3], the new DM-MEA has shown to be a useful tool for in-vitro neuroscience studies, especially for network studies}, keywords = {ETH-CMOS-MEA, Stimulation}, pubstate = {published}, tppubtype = {conference} } Close Recording and analysis of neuronal signals can provide much insight into how neurons process information and communicate with each other. Recent advancements of microelectrode-array (MEA) technology provide unprecedented means to study neuronal signals and network behavior in in vitro and in vivo applications [1], [2]. The trade-off between noise performance, power consumption and electrode density, however, remains a major challenge in MEA design. To balance this tradeoff, we designed a Dual-mode (DM) MEA that combines two major types of readout schemes, i.e., the active-pixel-sensor (APS) and switch-matrix (SM) schemes, in order to achieve high electrode density and high signal-to-noise ratio (SNR) at the same time. Based on a previous prototype [3], the new DM-MEA has shown to be a useful tool for in-vitro neuroscience studies, especially for network studies Close https://https://www.frontiersin.org/Community/AbstractDetails.aspx?ABS_DOI=10.33[...] doi:10.3389/conf.fncel.2018.38.00088 Close
	Fiscella, Michele; Leary, Noelle; Ronchi, Silvia; Hierlemann, Andreas Electrophysiological phenotype characterization of human iPSC-derived dopaminergic neuronal lines by means of high-resolution microelelectrode arrays Conference 11th International Meeting on Substrate Integrated Microelectrode Arrays (MEA Meeting) Reutlingen, Germany, 2018. Abstract \| Links \| BibTeX \| タグ: HD-MEA, IPSC @conference{Fiscella2018c, title = {Electrophysiological phenotype characterization of human iPSC-derived dopaminergic neuronal lines by means of high-resolution microelelectrode arrays}, author = {Michele Fiscella and Noelle Leary and Silvia Ronchi and Andreas Hierlemann}, url = {https://www.frontiersin.org/Community/AbstractDetails.aspx?ABS_DOI=10.3389/conf.fncel.2018.38.00014&eid=5473&sname=MEA_Meeting_2018_%7C_11th_International_Meeting_on_Substrate_Integrated_Microelectrode_Arrays}, doi = {10.3389/conf.fncel.2018.38.00014}, year = {2018}, date = {2018-07-04}, address = {Reutlingen, Germany}, organization = {11th International Meeting on Substrate Integrated Microelectrode Arrays (MEA Meeting)}, abstract = {High-resolution-microelectrode-array (MEA) technology enables to study neuronal dynamics at different scales, ranging from axonal physiology to network connectivity (Müller et. al, Lab on a Chip, 2015). We have used this MEA technology to characterize and compare the electrical phenotypes of commercially available human dopaminergic neurons (iCell DopaNeurons, MyCell DopaNeurons A53T α-synuclein, Cellular Dynamics International, Madison, WI, US). Furthermore, we have studied the effect of human astrocytes (iCell Astrocytes, Cellular Dynamics International, Madison, WI, US) on neural culture development. Astrocyte/neuron co-cultures showed higher signal amplitudes and higher firing rates than neural cultures without astrocytes. Adding astrocytes to neural cultures changed the whole culture morphology by promoting cell clustering. Interestingly, astrocyte/neuron co-cultures showed a lower sample-to-sample variability across multiple MEA recording sessions compared to neural cultures without astrocytes. We compared velocities of action potential propagation along axons between dopaminergic A53T α-synuclein neurons and the wild-type isogenic control cell line. We found that in both, wild-type and disease-model neurons, axonal action potential propagation velocities were lower than, for example, in rat primary cortical neurons (Bakkum et. al, Nature Communications, 2013). Furthermore, we found different axonal action-potential-velocity development profiles of A53T α-synuclein dopaminergic neurons and the wild-typecell line. Finally, we were able to precisely and reproducibly evoke action potentials in individual single human IPSC-derived neurons through subcellular-resolution electrical stimulation. High-resolution MEA systems enable to access novel electrophysiological parameters of iPSC-derived neurons, which can be potentially used as biomarkers for phenotype screening and drug testing.}, keywords = {HD-MEA, IPSC}, pubstate = {published}, tppubtype = {conference} } Close High-resolution-microelectrode-array (MEA) technology enables to study neuronal dynamics at different scales, ranging from axonal physiology to network connectivity (Müller et. al, Lab on a Chip, 2015). We have used this MEA technology to characterize and compare the electrical phenotypes of commercially available human dopaminergic neurons (iCell DopaNeurons, MyCell DopaNeurons A53T α-synuclein, Cellular Dynamics International, Madison, WI, US). Furthermore, we have studied the effect of human astrocytes (iCell Astrocytes, Cellular Dynamics International, Madison, WI, US) on neural culture development. Astrocyte/neuron co-cultures showed higher signal amplitudes and higher firing rates than neural cultures without astrocytes. Adding astrocytes to neural cultures changed the whole culture morphology by promoting cell clustering. Interestingly, astrocyte/neuron co-cultures showed a lower sample-to-sample variability across multiple MEA recording sessions compared to neural cultures without astrocytes. We compared velocities of action potential propagation along axons between dopaminergic A53T α-synuclein neurons and the wild-type isogenic control cell line. We found that in both, wild-type and disease-model neurons, axonal action potential propagation velocities were lower than, for example, in rat primary cortical neurons (Bakkum et. al, Nature Communications, 2013). Furthermore, we found different axonal action-potential-velocity development profiles of A53T α-synuclein dopaminergic neurons and the wild-typecell line. Finally, we were able to precisely and reproducibly evoke action potentials in individual single human IPSC-derived neurons through subcellular-resolution electrical stimulation. High-resolution MEA systems enable to access novel electrophysiological parameters of iPSC-derived neurons, which can be potentially used as biomarkers for phenotype screening and drug testing. Close https://www.frontiersin.org/Community/AbstractDetails.aspx?ABS_DOI=10.3389/conf.[...] doi:10.3389/conf.fncel.2018.38.00014 Close
	Urwyler, Cedar; Bounik, Raziyeh; Viswam, Vijay; Hierlemann, Andreas Electrical impedance tomography on high-density microelectrode arrays Conference 11th International Meeting on Substrate Integrated Microelectrode Arrays (MEA Meeting) Reutlingen, Germany, 2018. Abstract \| Links \| BibTeX \| タグ: HD-MEA @conference{Urwyler2018, title = {Electrical impedance tomography on high-density microelectrode arrays}, author = {Cedar Urwyler and Raziyeh Bounik and Vijay Viswam and Andreas Hierlemann }, url = {https://www.frontiersin.org/10.3389/conf.fncel.2018.38.00084/event_abstract}, doi = {10.3389/conf.fncel.2018.38.00084}, year = {2018}, date = {2018-07-04}, address = {Reutlingen, Germany}, organization = {11th International Meeting on Substrate Integrated Microelectrode Arrays (MEA Meeting)}, abstract = {Electrical impedance tomography (EIT) is a non-invasive, label-free imaging technique that enables to reconstruct the conductivity distribution in a body from a series of impedance measurements. Impedance measurements can be used to determine the position, morphology, and growth of cells or tissues, as well as pathological signs, e.g., precancerous tissue conditions (Gersing 1999). The newest high-density microelectrode array (MEA) system developed in our group features 59,760 integrated electrodes (Dragas et al. 2017). The chip features a variety of electrophysiological functions: Action-potential recording (2048 channels), cyclic voltammetry (28 channels), local-field-potential recording (32 channels) and extracellular stimulation (16 channels) [Fig 1A]. The chip can also measure impedance through 32 channels, which enables EIT measurements. We were able to establish a proof of concept for EIT (Viswam et al. 2017). The current goal of this project is to develop an impedance measurement protocol and an appropriate reconstruction algorithm that allow for single-cell-resolution impedance imaging.}, keywords = {HD-MEA}, pubstate = {published}, tppubtype = {conference} } Close Electrical impedance tomography (EIT) is a non-invasive, label-free imaging technique that enables to reconstruct the conductivity distribution in a body from a series of impedance measurements. Impedance measurements can be used to determine the position, morphology, and growth of cells or tissues, as well as pathological signs, e.g., precancerous tissue conditions (Gersing 1999). The newest high-density microelectrode array (MEA) system developed in our group features 59,760 integrated electrodes (Dragas et al. 2017). The chip features a variety of electrophysiological functions: Action-potential recording (2048 channels), cyclic voltammetry (28 channels), local-field-potential recording (32 channels) and extracellular stimulation (16 channels) [Fig 1A]. The chip can also measure impedance through 32 channels, which enables EIT measurements. We were able to establish a proof of concept for EIT (Viswam et al. 2017). The current goal of this project is to develop an impedance measurement protocol and an appropriate reconstruction algorithm that allow for single-cell-resolution impedance imaging. Close https://www.frontiersin.org/10.3389/conf.fncel.2018.38.00084/event_abstract doi:10.3389/conf.fncel.2018.38.00084 Close
	Schroter, Manuel; Girr, Monika; Boos, Julia Alicia; Renner, Magdalena; Gazorpak, Mahshid; Gong, Wei; Bartram, Julian; Muller, Jan; Hierlemann, Andreas Mapping neuronal network dynamics in developing cerebral organoids Conference 11th International Meeting on Substrate Integrated Microelectrode Arrays (MEA Meeting) Reutlingen, Germany, 2018. Abstract \| Links \| BibTeX \| タグ: Neuronal Networks, Organoids @conference{Schroter2018, title = {Mapping neuronal network dynamics in developing cerebral organoids}, author = {Manuel Schroter and Monika Girr and Julia Alicia Boos and Magdalena Renner and Mahshid Gazorpak and Wei Gong and Julian Bartram and Jan Muller and Andreas Hierlemann}, url = {https://www.frontiersin.org/10.3389/conf.fncel.2018.38.00066/event_abstract}, doi = {10.3389/conf.fncel.2018.38.00066}, year = {2018}, date = {2018-07-04}, address = {Reutlingen, Germany}, organization = {11th International Meeting on Substrate Integrated Microelectrode Arrays (MEA Meeting)}, abstract = {Cerebral organoids represent an attractive, novel model system to study early brain development in vitro (Di Lullo and Kriegstein, 2017). Although recent evidence shows that cerebral organoids do recapitulate fundamental milestones of early brain morphogenesis (Lancaster and Knoblich, 2014), the emergence and functionality of brain-organoid neuronal connectivity has not been studied systematically yet. In this study, we apply high-density micro-electrode arrays (MEAs) to record from developing mouse cerebral organoids and characterize their spontaneous neuronal activity. Results provide first evidence on the potential of MEAs as a platform to study the role of spontaneous neuronal activity during brain organoid development and formation of functional microcircuits. }, keywords = {Neuronal Networks, Organoids}, pubstate = {published}, tppubtype = {conference} } Close Cerebral organoids represent an attractive, novel model system to study early brain development in vitro (Di Lullo and Kriegstein, 2017). Although recent evidence shows that cerebral organoids do recapitulate fundamental milestones of early brain morphogenesis (Lancaster and Knoblich, 2014), the emergence and functionality of brain-organoid neuronal connectivity has not been studied systematically yet. In this study, we apply high-density micro-electrode arrays (MEAs) to record from developing mouse cerebral organoids and characterize their spontaneous neuronal activity. Results provide first evidence on the potential of MEAs as a platform to study the role of spontaneous neuronal activity during brain organoid development and formation of functional microcircuits. Close https://www.frontiersin.org/10.3389/conf.fncel.2018.38.00066/event_abstract doi:10.3389/conf.fncel.2018.38.00066 Close
	Bartram, Julian; Schroter, Manuel; Ronchi, Silvia; Emmenegger, Vishalini; Muller, Jan; Hierlemann, Andreas Probing synaptic connectivity and function using high-density microelectrode arrays and whole-cell patch-clamp recordings Conference 11th International Meeting on Substrate Integrated Microelectrode Arrays (MEA Meeting) Reutlingen, Germany, 2018. Abstract \| Links \| BibTeX \| タグ: HD-MEA @conference{Bartram2018b, title = {Probing synaptic connectivity and function using high-density microelectrode arrays and whole-cell patch-clamp recordings}, author = {Julian Bartram and Manuel Schroter and Silvia Ronchi and Vishalini Emmenegger and Jan Muller and Andreas Hierlemann}, url = {https://www.frontiersin.org/10.3389/conf.fncel.2018.38.00085/5473/MEA_Meeting_2018_%7C_11th_International_Meeting_on_Substrate_Integrated_Microelectrode_Arrays/all_events/event_abstract}, doi = {10.3389/conf.fncel.2018.38.00085}, year = {2018}, date = {2018-07-04}, address = {Reutlingen, Germany}, organization = {11th International Meeting on Substrate Integrated Microelectrode Arrays (MEA Meeting)}, abstract = {Synaptic efficacy and synapse number of monosynaptic connections between neurons are often regulated by the spiking activity of the respective pre- and postsynaptic cell. Progress towards a better understanding of the rules and mechanisms that underlie such modifications has been limited due to the difficulties associated with simultaneously studying plasticity at multiple synaptic inputs. Here, we provide a solution to this problem by combining cutting-edge high-density microelectrode array (HD-MEA) technology with the patch-clamp technique. While the latter allows for accurate measurement of postsynaptic currents or potentials, evoked by individual synaptic activation, the HD-MEA technology provides large-scale information about unit activity and allows for selective stimulation of neurons, including multiple presynaptic cells. The proposed approach has been applied to comprehensively examine forms of homeostatic plasticity – a collection of crucial processes acting at different temporal scales in order to stabilize neuronal firing rates. We report on a characterization of classic synaptic scaling operating in mature cortical networks and propose a novel model for the study of homeostatic plasticity during natural network states. }, keywords = {HD-MEA}, pubstate = {published}, tppubtype = {conference} } Close Synaptic efficacy and synapse number of monosynaptic connections between neurons are often regulated by the spiking activity of the respective pre- and postsynaptic cell. Progress towards a better understanding of the rules and mechanisms that underlie such modifications has been limited due to the difficulties associated with simultaneously studying plasticity at multiple synaptic inputs. Here, we provide a solution to this problem by combining cutting-edge high-density microelectrode array (HD-MEA) technology with the patch-clamp technique. While the latter allows for accurate measurement of postsynaptic currents or potentials, evoked by individual synaptic activation, the HD-MEA technology provides large-scale information about unit activity and allows for selective stimulation of neurons, including multiple presynaptic cells. The proposed approach has been applied to comprehensively examine forms of homeostatic plasticity – a collection of crucial processes acting at different temporal scales in order to stabilize neuronal firing rates. We report on a characterization of classic synaptic scaling operating in mature cortical networks and propose a novel model for the study of homeostatic plasticity during natural network states. Close https://www.frontiersin.org/10.3389/conf.fncel.2018.38.00085/5473/MEA_Meeting_20[...] doi:10.3389/conf.fncel.2018.38.00085 Close
	da Drinnenberg Antonia; Franke, Felix; Morikawa Rei Jüttner; Hillier Daniel; Hantz Peter; Hierlemann Andreas; Azeredo Silveira Rava; Roska Botond K; How diverse retinal functions arise from feedback at the first visual synapse Journal Article Neuron, 99 (1), pp. 117-134, 2018. Abstract \| Links \| BibTeX \| タグ: Retina @article{Drinnenberg2018, title = {How diverse retinal functions arise from feedback at the first visual synapse}, author = {Drinnenberg, Antonia; Franke, Felix; Morikawa, Rei K; Jüttner; Hillier, Daniel; Hantz, Peter; Hierlemann, Andreas; Azeredo da Silveira, Rava; Roska, Botond}, url = {https://www.cell.com/neuron/fulltext/S0896-6273(18)30469-0}, doi = {10.1016/j.neuron.2018.06.001}, year = {2018}, date = {2018-06-21}, journal = {Neuron}, volume = {99}, number = {1}, pages = {117-134}, abstract = {Many brain regions contain local interneurons of distinct types. How does an interneuron type contribute to the input-output transformations of a given brain region? We addressed this question in the mouse retina by chemogenetically perturbing horizontal cells, an interneuron type providing feedback at the first visual synapse, while monitoring the light-driven spiking activity in thousands of ganglion cells, the retinal output neurons. We uncovered six reversible perturbation-induced effects in the response dynamics and response range of ganglion cells. The effects were enhancing or suppressive, occurred in different response epochs, and depended on the ganglion cell type. A computational model of the retinal circuitry reproduced all perturbation-induced effects and led us to assign specific functions to horizontal cells with respect to different ganglion cell types. Our combined experimental and theoretical work reveals how a single interneuron type can differentially shape the dynamical properties of distinct output channels of a brain region.}, keywords = {Retina}, pubstate = {published}, tppubtype = {article} } Close Many brain regions contain local interneurons of distinct types. How does an interneuron type contribute to the input-output transformations of a given brain region? We addressed this question in the mouse retina by chemogenetically perturbing horizontal cells, an interneuron type providing feedback at the first visual synapse, while monitoring the light-driven spiking activity in thousands of ganglion cells, the retinal output neurons. We uncovered six reversible perturbation-induced effects in the response dynamics and response range of ganglion cells. The effects were enhancing or suppressive, occurred in different response epochs, and depended on the ganglion cell type. A computational model of the retinal circuitry reproduced all perturbation-induced effects and led us to assign specific functions to horizontal cells with respect to different ganglion cell types. Our combined experimental and theoretical work reveals how a single interneuron type can differentially shape the dynamical properties of distinct output channels of a brain region. Close https://www.cell.com/neuron/fulltext/S0896-6273(18)30469-0 doi:10.1016/j.neuron.2018.06.001 Close
	Fiscella, Michele; Leary, Noelle; Ronchi, Silvia; Hierlemann, Andreas Electrophysiological phenotype characterization of human iPSC-derived dopaminergic neuronal lines by means of high-resolution microelelectrode arrays Conference W-2151 , International Society for Stem Cell Research (ISSCR) Annual Meeting Melbourne, Australia, 2018. Abstract \| Links \| BibTeX \| タグ: HD-MEA, IPSC @conference{Fiscella2018b, title = {Electrophysiological phenotype characterization of human iPSC-derived dopaminergic neuronal lines by means of high-resolution microelelectrode arrays}, author = {Michele Fiscella and Noelle Leary and Silvia Ronchi and Andreas Hierlemann }, url = {http://www.isscr.org/docs/default-source/2018-melbourne-ann-mtng/66670-isscr-abstracts_with-links.pdf?sfvrsn=4&utm_source=ISSCR-Informz&utm_medium=email&utm_campaign=default}, year = {2018}, date = {2018-06-20}, volume = {W-2151}, address = {Melbourne, Australia}, organization = {International Society for Stem Cell Research (ISSCR) Annual Meeting}, abstract = {High-resolution-microelectrode-array (MEA) technology enables to study neuronal dynamics at different scales, ranging from axonal physiology to network connectivity (Müller et. al, Lab on a Chip, 2015). We have used this MEA technology to characterize and compare the electrical phenotypes of commercially available human dopaminergic neurons (iCell DopaNeurons, MyCell DopaNeurons A53T α-synuclein, Cellular Dynamics International, Madison, WI, US). Furthermore, we have studied the effect of human astrocytes (iCell Astrocytes, Cellular Dynamics International, Madison, WI, US) on neural culture development. Astrocyte/neuron co- cultures showed higher signal amplitudes and higher firing rates than neural cultures without astrocytes. Adding astrocytes to neural cultures changed the whole culture morphology by promoting cell clustering. Interestingly, astrocyte/neuron co-cultures showed a lower sample-to-sample variability across multiple MEA recordings compared to neural cultures without astrocytes. We compared action potential propagation velocities along axons between dopaminergic A53T α-synuclein neurons and the wild-type isogenic control cell line. We found that in both, wild-type and disease model neurons, axonal action potential propagation velocities were lower than in rat primary cortical neurons. Furthermore, we found different axonal action potential velocity development profiles of A53T α-synuclein dopaminergic neurons and the wild-type counterpart. Finally, we were able to precisely evoke action potentials in individual single human neurons by subcellular- resolution electrical stimulation. High-resolution MEA systems enable to access novel electrophysiological parameters of iPSC-derived neurons, which can be potentially used as biomarkers for phenotype screening and drug testing.}, keywords = {HD-MEA, IPSC}, pubstate = {published}, tppubtype = {conference} } Close High-resolution-microelectrode-array (MEA) technology enables to study neuronal dynamics at different scales, ranging from axonal physiology to network connectivity (Müller et. al, Lab on a Chip, 2015). We have used this MEA technology to characterize and compare the electrical phenotypes of commercially available human dopaminergic neurons (iCell DopaNeurons, MyCell DopaNeurons A53T α-synuclein, Cellular Dynamics International, Madison, WI, US). Furthermore, we have studied the effect of human astrocytes (iCell Astrocytes, Cellular Dynamics International, Madison, WI, US) on neural culture development. Astrocyte/neuron co- cultures showed higher signal amplitudes and higher firing rates than neural cultures without astrocytes. Adding astrocytes to neural cultures changed the whole culture morphology by promoting cell clustering. Interestingly, astrocyte/neuron co-cultures showed a lower sample-to-sample variability across multiple MEA recordings compared to neural cultures without astrocytes. We compared action potential propagation velocities along axons between dopaminergic A53T α-synuclein neurons and the wild-type isogenic control cell line. We found that in both, wild-type and disease model neurons, axonal action potential propagation velocities were lower than in rat primary cortical neurons. Furthermore, we found different axonal action potential velocity development profiles of A53T α-synuclein dopaminergic neurons and the wild-type counterpart. Finally, we were able to precisely evoke action potentials in individual single human neurons by subcellular- resolution electrical stimulation. High-resolution MEA systems enable to access novel electrophysiological parameters of iPSC-derived neurons, which can be potentially used as biomarkers for phenotype screening and drug testing. Close http://www.isscr.org/docs/default-source/2018-melbourne-ann-mtng/66670-isscr-abs[...] Close
	Bakkum Douglas J; Radivojevic, Milos; Obien Marie Engelene; Jaeckel David; Frey Urs; Takahashi Hirokazu; Hierlemann Andreas The axon initial segment drives the neuron's extracellular action potential Journal Article bioRxiv, pp. 1-30, 2018. Abstract \| Links \| BibTeX \| タグ: ETH-CMOS-MEA @article{Bakkum2018, title = {The axon initial segment drives the neuron's extracellular action potential}, author = {Bakkum, Douglas J; Radivojevic, Milos; Obien, Marie Engelene; Jaeckel, David; Frey, Urs; Takahashi, Hirokazu; Hierlemann, Andreas }, url = {https://www.biorxiv.org/content/early/2018/02/16/266734}, doi = {10.1101/266734 }, year = {2018}, date = {2018-02-16}, journal = {bioRxiv}, pages = {1-30}, abstract = {Extracellular voltage fields produced by a neuron's action potentials provide a primary means for studying neuron function, yet their biophysical sources remain ambiguous. The neuron's soma and dendrites are thought to drive the extracellular action potential (EAP), while the axon is usually ignored. However, by recording voltages of single neurons in dissociated rat cortical cultures and Purkinje cells in acute mouse cerebellar slices at hundreds of sites, we find instead that the axon initial segment dominates the EAP, and, surprisingly, the soma shows little or no influence. As expected, this signal has negative polarity (charge entering the cell) and initiates at the distal end. Interestingly, signals with positive polarity (charge exiting the cell) occur near some but not all dendritic branches and occur after a delay. Such basic knowledge about which neuronal compartments contribute to the extracellular voltage field is important for interpreting results from all electrical readout schemes. Moreover, this finding shows that changes in the AIS position and function can be observed in high spatiotemporal detail by means of high-density extracellular electrophysiology.}, keywords = {ETH-CMOS-MEA}, pubstate = {published}, tppubtype = {article} } Close Extracellular voltage fields produced by a neuron's action potentials provide a primary means for studying neuron function, yet their biophysical sources remain ambiguous. The neuron's soma and dendrites are thought to drive the extracellular action potential (EAP), while the axon is usually ignored. However, by recording voltages of single neurons in dissociated rat cortical cultures and Purkinje cells in acute mouse cerebellar slices at hundreds of sites, we find instead that the axon initial segment dominates the EAP, and, surprisingly, the soma shows little or no influence. As expected, this signal has negative polarity (charge entering the cell) and initiates at the distal end. Interestingly, signals with positive polarity (charge exiting the cell) occur near some but not all dendritic branches and occur after a delay. Such basic knowledge about which neuronal compartments contribute to the extracellular voltage field is important for interpreting results from all electrical readout schemes. Moreover, this finding shows that changes in the AIS position and function can be observed in high spatiotemporal detail by means of high-density extracellular electrophysiology. Close https://www.biorxiv.org/content/early/2018/02/16/266734 doi:10.1101/266734 Close
2017
	Viswam, Vijay; Obien, Marie Engelene J; Frey, Urs; Franke, Felix; Hierlemann, Andreas Acquisition of Bioelectrical Signals with Small Electrodes Conference 2017 IEEE Biomedical Circuits and Systems Conference (BioCAS) Turin, Italy, 2017. Abstract \| Links \| BibTeX \| タグ: Electrodes, ETH-CMOS-MEA @conference{Viswam2017, title = {Acquisition of Bioelectrical Signals with Small Electrodes}, author = {Vijay Viswam and Marie Engelene J. Obien and Urs Frey and Felix Franke and Andreas Hierlemann}, url = {https://ieeexplore.ieee.org/document/8325216}, doi = {10.1109/BIOCAS.2017.8325216}, year = {2017}, date = {2017-10-19}, address = {Turin, Italy}, organization = {2017 IEEE Biomedical Circuits and Systems Conference (BioCAS)}, abstract = {Although the mechanisms of recording bioelectrical signals from different types of electrogenic cells (neurons, cardiac cells etc.) by means of planar metal electrodes have been extensively studied, the recording characteristics and conditions for very small electrode sizes are not yet established. Here, we present a combined experimental and computational approach to elucidate, how the electrode size influences the recorded signals, and how inherent properties of the electrode, such as impedance, noise, and transmission characteristics shape the signal. We demonstrate that good quality recordings can be achieved with electrode diameters of less than 10 μm, provided that impedance reduction measures have been implemented and provided that a set of requirements for signal amplification has been met.}, keywords = {Electrodes, ETH-CMOS-MEA}, pubstate = {published}, tppubtype = {conference} } Close Although the mechanisms of recording bioelectrical signals from different types of electrogenic cells (neurons, cardiac cells etc.) by means of planar metal electrodes have been extensively studied, the recording characteristics and conditions for very small electrode sizes are not yet established. Here, we present a combined experimental and computational approach to elucidate, how the electrode size influences the recorded signals, and how inherent properties of the electrode, such as impedance, noise, and transmission characteristics shape the signal. We demonstrate that good quality recordings can be achieved with electrode diameters of less than 10 μm, provided that impedance reduction measures have been implemented and provided that a set of requirements for signal amplification has been met. Close https://ieeexplore.ieee.org/document/8325216 doi:10.1109/BIOCAS.2017.8325216 Close
	Radivojevic, Milos; Franke, Felix; Altermatt, Michael; Müller, Jan; Hierlemann, Andreas; Bakkum, Douglas J Tracking individual action potentials throughout mammalian axonal arbors Journal Article eLife, 6 , pp. 1-23, 2017, ISSN: 2050-084X. Abstract \| Links \| BibTeX \| タグ: Data Analysis, ETH-CMOS-MEA, Neuronal Networks, Stimulation @article{Radivojevic2017, title = {Tracking individual action potentials throughout mammalian axonal arbors}, author = {Milos Radivojevic and Felix Franke and Michael Altermatt and Jan Müller and Andreas Hierlemann and Douglas J Bakkum}, url = {https://elifesciences.org/articles/30198}, doi = {10.7554/eLife.30198}, issn = {2050-084X}, year = {2017}, date = {2017-10-09}, journal = {eLife}, volume = {6}, pages = {1-23}, abstract = {Axons are neuronal processes specialized for conduction of action potentials (APs). The timing and temporal precision of APs when they reach each of the synapses are fundamentally important for information processing in the brain. Due to small diameters of axons, direct recording of single AP transmission is challenging. Consequently, most knowledge about axonal conductance derives from modeling studies or indirect measurements. We demonstrate a method to noninvasively and directly record individual APs propagating along millimeter-length axonal arbors in cortical cultures with hundreds of microelectrodes at microsecond temporal resolution. We find that cortical axons conduct single APs with high temporal precision (~100 µs arrival time jitter per mm length) and reliability: in more than 8,000,000 recorded APs, we did not observe any conduction or branch-point failures. Upon high-frequency stimulation at 100 Hz, successive became slower, and their arrival time precision decreased by 20% and 12% for the 100th AP, respectively.}, keywords = {Data Analysis, ETH-CMOS-MEA, Neuronal Networks, Stimulation}, pubstate = {published}, tppubtype = {article} } Close Axons are neuronal processes specialized for conduction of action potentials (APs). The timing and temporal precision of APs when they reach each of the synapses are fundamentally important for information processing in the brain. Due to small diameters of axons, direct recording of single AP transmission is challenging. Consequently, most knowledge about axonal conductance derives from modeling studies or indirect measurements. We demonstrate a method to noninvasively and directly record individual APs propagating along millimeter-length axonal arbors in cortical cultures with hundreds of microelectrodes at microsecond temporal resolution. We find that cortical axons conduct single APs with high temporal precision (~100 µs arrival time jitter per mm length) and reliability: in more than 8,000,000 recorded APs, we did not observe any conduction or branch-point failures. Upon high-frequency stimulation at 100 Hz, successive became slower, and their arrival time precision decreased by 20% and 12% for the 100th AP, respectively. Close https://elifesciences.org/articles/30198 doi:10.7554/eLife.30198 Close
	Tajima Satohiro; Mita, Takeshi; Bakkum Douglas Takahashi Hirokazu; Toyoizumi Taro J; Locally embedded presages of global network bursts Journal Article National Academy of Sciences, pp. 1-6, 2017, ISSN: 0027-8424. Abstract \| Links \| BibTeX \| タグ: Neuronal Networks @article{Tajima2017, title = {Locally embedded presages of global network bursts}, author = {Tajima, Satohiro; Mita, Takeshi; Bakkum, Douglas J; Takahashi, Hirokazu; Toyoizumi, Taro}, editor = {Sejnowski, Terrence J}, url = {http://www.pnas.org/content/114/36/9517}, doi = {10.1073/pnas.1705981114 }, issn = {0027-8424}, year = {2017}, date = {2017-08-18}, journal = {National Academy of Sciences}, pages = {1-6}, abstract = {Spontaneous, synchronous bursting of neural population is a widely observed phenomenon in nervous networks, which is considered important for functions and dysfunctions of the brain. However, how the global synchrony across a large number of neurons emerges from an initially nonbursting network state is not fully understood. In this study, we develop a state-space reconstruction method combined with high-resolution recordings of cultured neurons. This method extracts deterministic signatures of upcoming global bursts in “local” dynamics of individual neurons during nonbursting periods. We find that local information within a single-cell time series can compare with or even outperform the global mean-field activity for predicting future global bursts. Moreover, the intercell variability in the burst predictability is found to reflect the network structure realized in the nonbursting periods. These findings suggest that deterministic local dynamics can predict seemingly stochastic global events in self-organized networks, implying the potential applications of the present methodology to detecting locally concentrated early warnings of spontaneous seizure occurrence in the brain.}, keywords = {Neuronal Networks}, pubstate = {published}, tppubtype = {article} } Close Spontaneous, synchronous bursting of neural population is a widely observed phenomenon in nervous networks, which is considered important for functions and dysfunctions of the brain. However, how the global synchrony across a large number of neurons emerges from an initially nonbursting network state is not fully understood. In this study, we develop a state-space reconstruction method combined with high-resolution recordings of cultured neurons. This method extracts deterministic signatures of upcoming global bursts in “local” dynamics of individual neurons during nonbursting periods. We find that local information within a single-cell time series can compare with or even outperform the global mean-field activity for predicting future global bursts. Moreover, the intercell variability in the burst predictability is found to reflect the network structure realized in the nonbursting periods. These findings suggest that deterministic local dynamics can predict seemingly stochastic global events in self-organized networks, implying the potential applications of the present methodology to detecting locally concentrated early warnings of spontaneous seizure occurrence in the brain. Close http://www.pnas.org/content/114/36/9517 doi:10.1073/pnas.1705981114 Close
	Shein-Idelson, Mark; Pammer, Lorenz; Hemberger, Mike; Laurent, Gilles Large-scale mapping of cortical synaptic projections with extracellular electrode arrays Journal Article Nature Methods, 14 (9), pp. 882–889, 2017, ISSN: 1548-7091. Abstract \| Links \| BibTeX \| タグ: Brain Slice, MaxOne, Neuronal Networks @article{Shein-Idelson2017, title = {Large-scale mapping of cortical synaptic projections with extracellular electrode arrays}, author = {Mark Shein-Idelson and Lorenz Pammer and Mike Hemberger and Gilles Laurent}, url = {http://www.nature.com/doifinder/10.1038/nmeth.4393}, doi = {10.1038/nmeth.4393}, issn = {1548-7091}, year = {2017}, date = {2017-08-14}, journal = {Nature Methods}, volume = {14}, number = {9}, pages = {882--889}, abstract = {Understanding circuit computation in the nervous system requires sampling activity over large neural populations and maximizing the number of features that can be extracted. By combining planar arrays of extracellular electrodes with the three-layered cortex of turtles, we show that synaptic signals induced along individual axons as well as action potentials can be easily captured. Two types of information can be extracted from these signals, the neuronal subtype (inhibitory or excitatory)—whose identification is more reliable than with traditional measures such as action potential width—and a (partial) spatial map of functional axonal projections from individual neurons. Because our approach is algorithmic, it can be carried out in parallel on hundreds of simultaneously recorded neurons. Combining our approach with soma triangulation, we reveal an axonal projection bias among a population of pyramidal neurons in turtle cortex and confirm this bias through anatomical reconstructions.}, keywords = {Brain Slice, MaxOne, Neuronal Networks}, pubstate = {published}, tppubtype = {article} } Close Understanding circuit computation in the nervous system requires sampling activity over large neural populations and maximizing the number of features that can be extracted. By combining planar arrays of extracellular electrodes with the three-layered cortex of turtles, we show that synaptic signals induced along individual axons as well as action potentials can be easily captured. Two types of information can be extracted from these signals, the neuronal subtype (inhibitory or excitatory)—whose identification is more reliable than with traditional measures such as action potential width—and a (partial) spatial map of functional axonal projections from individual neurons. Because our approach is algorithmic, it can be carried out in parallel on hundreds of simultaneously recorded neurons. Combining our approach with soma triangulation, we reveal an axonal projection bias among a population of pyramidal neurons in turtle cortex and confirm this bias through anatomical reconstructions. Close http://www.nature.com/doifinder/10.1038/nmeth.4393 doi:10.1038/nmeth.4393 Close
	Obien, Marie Engelene J; Zorzi, Giulio; Hierlemann, Andreas Mapping neuron cluster development based on axonal action potential propagation Conference The 40th Annual Meeting of the Japan Neuroscience Society Chiba, Japan, 2017. BibTeX \| タグ: Action Potential, Neuronal Networks @conference{Obien2017, title = {Mapping neuron cluster development based on axonal action potential propagation}, author = {Marie Engelene J. Obien and Giulio Zorzi and Andreas Hierlemann}, year = {2017}, date = {2017-07-20}, address = {Chiba, Japan}, organization = {The 40th Annual Meeting of the Japan Neuroscience Society}, keywords = {Action Potential, Neuronal Networks}, pubstate = {published}, tppubtype = {conference} } Close
	Diggelmann, Roland; Fiscella, Michele; Hierlemann, Andreas; Franke, Felix Pre-whitening as a means to improve dimensionality reduction and simplify clustering in spike-sorters for multi-electrode recordings Conference 26th Annual Computational Neuroscience Meeting (CNS2017) Antwerp, Belgium , 2017. Abstract \| Links \| BibTeX \| タグ: Spike Sorting @conference{Diggelmann2017, title = {Pre-whitening as a means to improve dimensionality reduction and simplify clustering in spike-sorters for multi-electrode recordings}, author = {Roland Diggelmann and Michele Fiscella and Andreas Hierlemann and Felix Franke}, url = {https://bmcneurosci.biomedcentral.com/articles/10.1186/s12868-017-0371-2}, year = {2017}, date = {2017-07-15}, address = {Antwerp, Belgium }, organization = {26th Annual Computational Neuroscience Meeting (CNS2017)}, abstract = {Spike sorting is the process to extract single neuronal activity from extracellular recordings. It makes use of the fact that spikes from a single neuron feature highly similar waveforms, whereas spikes from different neurons have different waveforms. Clustering algorithms are used to find groups of similar spikes that putatively originated from the same neuron. However, since spike waveforms especially in multi-electrode recordings can have a high dimensionality, their dimensionality needs to be reduced before clustering. Principal component analysis (PCA) is one of the most commonly employed dimensionality reduction methods for this purpose [1]. It reduces the dimensions to those where the variance of the data was highest, presumably those along which the waveforms of separate neurons differ most strongly, However, if the noise is not uniform in all dimensions, high variability can also mean high noise, which would render a dimension useless for discrimination. We, therefore, propose an additional pre-whitening step before PCA and discuss two beneficial effects on the subsequent clustering. We illustrate these effects by using spikes from retinal ganglion cells recorded with high-density multi-electrode arrays (HD-MEA).}, keywords = {Spike Sorting}, pubstate = {published}, tppubtype = {conference} } Close Spike sorting is the process to extract single neuronal activity from extracellular recordings. It makes use of the fact that spikes from a single neuron feature highly similar waveforms, whereas spikes from different neurons have different waveforms. Clustering algorithms are used to find groups of similar spikes that putatively originated from the same neuron. However, since spike waveforms especially in multi-electrode recordings can have a high dimensionality, their dimensionality needs to be reduced before clustering. Principal component analysis (PCA) is one of the most commonly employed dimensionality reduction methods for this purpose [1]. It reduces the dimensions to those where the variance of the data was highest, presumably those along which the waveforms of separate neurons differ most strongly, However, if the noise is not uniform in all dimensions, high variability can also mean high noise, which would render a dimension useless for discrimination. We, therefore, propose an additional pre-whitening step before PCA and discuss two beneficial effects on the subsequent clustering. We illustrate these effects by using spikes from retinal ganglion cells recorded with high-density multi-electrode arrays (HD-MEA). Close https://bmcneurosci.biomedcentral.com/articles/10.1186/s12868-017-0371-2 Close
	Viswam, Vijay; Bounik, Raziyeh; Shadmani, Amir; Dragas, Jelena; Obien, Marie; Müller, Jan; Chen, Yihui; Hierlemann1, Andreas High-density mapping of brain slices using a large multi-functional high-density CMOS microelectrode array system Conference 2017 19th International Conference on Solid-State Sensors, Actuators and Microsystems (TRANSDUCERS) 2017. Abstract \| Links \| BibTeX \| タグ: ETH-CMOS-MEA @conference{Viswam2017c, title = {High-density mapping of brain slices using a large multi-functional high-density CMOS microelectrode array system}, author = {Vijay Viswam and Raziyeh Bounik and Amir Shadmani and Jelena Dragas and Marie Obien and Jan Müller and Yihui Chen and Andreas Hierlemann1}, url = {https://ieeexplore.ieee.org/document/7994006}, doi = {10.1109/TRANSDUCERS.2017.7994006}, year = {2017}, date = {2017-06-18}, organization = {2017 19th International Conference on Solid-State Sensors, Actuators and Microsystems (TRANSDUCERS)}, abstract = {We present a CMOS-based high-density microelectrode array (HD-MEA) system that enables high-density mapping of brain slices in-vitrowith multiple readout modalities. The 4.48×2.43 mm2 array consists of 59,760 micro-electrodes at 13.5 μm pitch (5487 electrodes/mm2). The overall system features 2048 action-potential, 32 local-field-potential and 32 current recording channels, 32 impedance-measurement and 28 neurotransmitter-detection channels and 16 voltage/ current stimulation channels. The system enables real-time and label-free monitoring of position, size, morphology and electrical activity of brain slices.}, keywords = {ETH-CMOS-MEA}, pubstate = {published}, tppubtype = {conference} } Close We present a CMOS-based high-density microelectrode array (HD-MEA) system that enables high-density mapping of brain slices in-vitrowith multiple readout modalities. The 4.48×2.43 mm2 array consists of 59,760 micro-electrodes at 13.5 μm pitch (5487 electrodes/mm2). The overall system features 2048 action-potential, 32 local-field-potential and 32 current recording channels, 32 impedance-measurement and 28 neurotransmitter-detection channels and 16 voltage/ current stimulation channels. The system enables real-time and label-free monitoring of position, size, morphology and electrical activity of brain slices. Close https://ieeexplore.ieee.org/document/7994006 doi:10.1109/TRANSDUCERS.2017.7994006 Close
	Viswam, Vijay; Bounik, Raziyeh; Shadmani, Amir; Dragas, Jelena; Obien, Marie Engelene J; Muller, Jan; Chen, Yihui; Hierlemann, Andreas High-density Mapping of Brain Slices Using a Large Multi-functional High-density CMOS Microelectrode Array System Conference 19th International Conference on Solid-State Sensors, Actuators and Microsystems (TRANSDUCERS) Kaohsiung, Taiwan, 2017, ISSN: 2167-0021. Abstract \| Links \| BibTeX \| タグ: Brain Slice, ETH-CMOS-MEA, HD-MEA @conference{Viswam2017b, title = {High-density Mapping of Brain Slices Using a Large Multi-functional High-density CMOS Microelectrode Array System}, author = {Vijay Viswam and Raziyeh Bounik and Amir Shadmani and Jelena Dragas and Marie Engelene J. Obien and Jan Muller and Yihui Chen and Andreas Hierlemann }, url = {https://ieeexplore.ieee.org/abstract/document/7994006}, doi = {10.1109/TRANSDUCERS.2017.7994006}, issn = {2167-0021}, year = {2017}, date = {2017-06-18}, pages = {135-138}, address = {Kaohsiung, Taiwan}, organization = {19th International Conference on Solid-State Sensors, Actuators and Microsystems (TRANSDUCERS)}, abstract = {We present a CMOS-based high-density microelectrode array (HD-MEA) system that enables high-density mapping of brain slices in-vitro with multiple readout modalities. The 4.48×2.43 mm 2 array consists of 59,760 micro-electrodes at 13.5 μm pitch (5487 electrodes/mm 2 ). The overall system features 2048 action-potential, 32 local-field-potential and 32 current recording channels, 32 impedance-measurement and 28 neurotransmitter-detection channels and 16 voltage/current stimulation channels. The system enables real-time and label-free monitoring of position, size, morphology and electrical activity of brain slices.}, keywords = {Brain Slice, ETH-CMOS-MEA, HD-MEA}, pubstate = {published}, tppubtype = {conference} } Close We present a CMOS-based high-density microelectrode array (HD-MEA) system that enables high-density mapping of brain slices in-vitro with multiple readout modalities. The 4.48×2.43 mm 2 array consists of 59,760 micro-electrodes at 13.5 μm pitch (5487 electrodes/mm 2 ). The overall system features 2048 action-potential, 32 local-field-potential and 32 current recording channels, 32 impedance-measurement and 28 neurotransmitter-detection channels and 16 voltage/current stimulation channels. The system enables real-time and label-free monitoring of position, size, morphology and electrical activity of brain slices. Close https://ieeexplore.ieee.org/abstract/document/7994006 doi:10.1109/TRANSDUCERS.2017.7994006 Close
	Frey, Urs; Obien, Marie Engelene J; Muller, Jan; Hierlemann, Andreas Technology Trends and Commercialization of High-density Microelectrode Arrays for Advanced In-vitro Electrophysiology Conference IEEE International Symposium on Circuits and Systems (ISCAS Baltimore, MD, USA, 2017, ISSN: 2379-447X. Abstract \| Links \| BibTeX \| タグ: HD-MEA, In-Vitro @conference{Frey2017, title = {Technology Trends and Commercialization of High-density Microelectrode Arrays for Advanced In-vitro Electrophysiology}, author = {Urs Frey and Marie Engelene J. Obien and Jan Muller and Andreas Hierlemann}, url = {https://ieeexplore.ieee.org/document/8050215/}, doi = {10.1109/ISCAS.2017.8050215}, issn = {2379-447X}, year = {2017}, date = {2017-05-28}, address = {Baltimore, MD, USA}, organization = {IEEE International Symposium on Circuits and Systems (ISCAS}, abstract = {Microelectrode arrays (MEAs) enable fast and high-throughput readout of cell's electrical signals. MEAs are currently used for phenotype characterization and drug toxicity/efficacy testing with iPSC-derived neurons and cardiomyocytes. A key advantage of MEAs is the capability to record and stimulate individual neurons at multiple sites simultaneously. We will present ongoing advancements of MEA technology, with a focus on achieving higher quality recordings by means of monolithic co-integration of circuitry on chip by using CMOS technology [1]. Such high-density MEAs with more than 3000 electrodes per mm2 are a suitable tool for capturing neuronal activity across various scales, including axons, somas, dendrites, entire neurons, and networks.}, keywords = {HD-MEA, In-Vitro}, pubstate = {published}, tppubtype = {conference} } Close Microelectrode arrays (MEAs) enable fast and high-throughput readout of cell's electrical signals. MEAs are currently used for phenotype characterization and drug toxicity/efficacy testing with iPSC-derived neurons and cardiomyocytes. A key advantage of MEAs is the capability to record and stimulate individual neurons at multiple sites simultaneously. We will present ongoing advancements of MEA technology, with a focus on achieving higher quality recordings by means of monolithic co-integration of circuitry on chip by using CMOS technology [1]. Such high-density MEAs with more than 3000 electrodes per mm2 are a suitable tool for capturing neuronal activity across various scales, including axons, somas, dendrites, entire neurons, and networks. Close https://ieeexplore.ieee.org/document/8050215/ doi:10.1109/ISCAS.2017.8050215 Close
	Hillier, Daniel; Fiscella, Michele; Drinnenberg, Antonia; Trenholm, Stuart; Rompani, Santiago B; Raics, Zoltan; Katona, Gergely; Jüttner, Josephine; Hierlemann, Andreas; Rozsa, Balazs; Roska, Botond Causal evidence for retina-dependent and -independent visual motion computations in mouse cortex Journal Article Nature Neuroscience, 20 (7), pp. 960–968, 2017, ISSN: 1097-6256. Abstract \| Links \| BibTeX \| タグ: MaxOne, Retina @article{Hillier2017, title = {Causal evidence for retina-dependent and -independent visual motion computations in mouse cortex}, author = {Daniel Hillier and Michele Fiscella and Antonia Drinnenberg and Stuart Trenholm and Santiago B Rompani and Zoltan Raics and Gergely Katona and Josephine Jüttner and Andreas Hierlemann and Balazs Rozsa and Botond Roska}, url = {http://www.nature.com/doifinder/10.1038/nn.4566}, doi = {10.1038/nn.4566}, issn = {1097-6256}, year = {2017}, date = {2017-05-22}, journal = {Nature Neuroscience}, volume = {20}, number = {7}, pages = {960--968}, abstract = {How neuronal computations in the sensory periphery contribute to computations in the cortex is not well understood. We examined this question in the context of visual-motion processing in the retina and primary visual cortex (V1) of mice. We disrupted retinal direction selectivity, either exclusively along the horizontal axis using FRMD7 mutants or along all directions by ablating starburst amacrine cells, and monitored neuronal activity in layer 2/3 of V1 during stimulation with visual motion. In control mice, we found an over-representation of cortical cells preferring posterior visual motion, the dominant motion direction an animal experiences when it moves forward. In mice with disrupted retinal direction selectivity, the over-representation of posterior-motion-preferring cortical cells disappeared, and their responses at higher stimulus speeds were reduced. This work reveals the existence of two functionally distinct, sensory-periphery-dependent and -independent computations of visual motion in the cortex.}, keywords = {MaxOne, Retina}, pubstate = {published}, tppubtype = {article} } Close How neuronal computations in the sensory periphery contribute to computations in the cortex is not well understood. We examined this question in the context of visual-motion processing in the retina and primary visual cortex (V1) of mice. We disrupted retinal direction selectivity, either exclusively along the horizontal axis using FRMD7 mutants or along all directions by ablating starburst amacrine cells, and monitored neuronal activity in layer 2/3 of V1 during stimulation with visual motion. In control mice, we found an over-representation of cortical cells preferring posterior visual motion, the dominant motion direction an animal experiences when it moves forward. In mice with disrupted retinal direction selectivity, the over-representation of posterior-motion-preferring cortical cells disappeared, and their responses at higher stimulus speeds were reduced. This work reveals the existence of two functionally distinct, sensory-periphery-dependent and -independent computations of visual motion in the cortex. Close http://www.nature.com/doifinder/10.1038/nn.4566 doi:10.1038/nn.4566 Close
	Bullmann Torsten; Radivojevic, Milos; Huber Stefan Deligkaris Kosmas; Hierlemann Andreas; Frey Urs T: Network Analysis Of High-Density Microelectrode Recordings Journal Article bioRxiv , (139436), pp. 1-23, 2017. Abstract \| Links \| BibTeX \| タグ: ETH-CMOS-MEA @article{Bullmann2017, title = {Network Analysis Of High-Density Microelectrode Recordings}, author = {Bullmann, Torsten; Radivojevic, Milos; Huber, Stefan T: Deligkaris, Kosmas; Hierlemann, Andreas; Frey, Urs }, url = {https://www.biorxiv.org/content/early/2017/05/18/139436 }, doi = {10.1101/139436}, year = {2017}, date = {2017-05-18}, journal = {bioRxiv }, number = {139436}, pages = {1-23}, abstract = {Extracellular voltage fields produced by a neuron's action potentials provide a primary means for studying neuron function, yet their biophysical sources remain ambiguous. The neuron's soma and dendrites are thought to drive the extracellular action potential (EAP), while the axon is usually ignored. However, by recording voltages of single neurons in dissociated rat cortical cultures and Purkinje cells in acute mouse cerebellar slices at hundreds of sites, we find instead that the axon initial segment dominates the EAP, and, surprisingly, the soma shows little or no influence. As expected, this signal has negative polarity (charge entering the cell) and initiates at the distal end. Interestingly, signals with positive polarity (charge exiting the cell) occur near some but not all dendritic branches and occur after a delay. Such basic knowledge about which neuronal compartments contribute to the extracellular voltage field is important for interpreting results from all electrical readout schemes. Moreover, this finding shows that changes in the AIS position and function can be observed in high spatiotemporal detail by means of high-density extracellular electrophysiology.}, keywords = {ETH-CMOS-MEA}, pubstate = {published}, tppubtype = {article} } Close Extracellular voltage fields produced by a neuron's action potentials provide a primary means for studying neuron function, yet their biophysical sources remain ambiguous. The neuron's soma and dendrites are thought to drive the extracellular action potential (EAP), while the axon is usually ignored. However, by recording voltages of single neurons in dissociated rat cortical cultures and Purkinje cells in acute mouse cerebellar slices at hundreds of sites, we find instead that the axon initial segment dominates the EAP, and, surprisingly, the soma shows little or no influence. As expected, this signal has negative polarity (charge entering the cell) and initiates at the distal end. Interestingly, signals with positive polarity (charge exiting the cell) occur near some but not all dendritic branches and occur after a delay. Such basic knowledge about which neuronal compartments contribute to the extracellular voltage field is important for interpreting results from all electrical readout schemes. Moreover, this finding shows that changes in the AIS position and function can be observed in high spatiotemporal detail by means of high-density extracellular electrophysiology. Close https://www.biorxiv.org/content/early/2017/05/18/139436 doi:10.1101/139436 Close
	Dragas, Jelena; Viswam, Vijay; Shadmani, Amir; Chen, Yihui; Bounik, Raziyeh; Stettler, Alexander; Radivojevic, Milos; Geissler, Sydney; Obien, Marie Engelene J; Müller, Jan; Hierlemann, Andreas A Multi-Functional Microelectrode Array Featuring 59760 Electrodes, 2048 Electrophysiology Channels, Stimulation, Impedance Measurement and Neurotransmitter Detection Channels Journal Article IEEE journal of solid-state circuits, 52 (6), pp. 1576-1590, 2017, ISSN: 0018-9200. Abstract \| Links \| BibTeX \| タグ: ETH-CMOS-MEA, MEA Technology @article{Dragas2017, title = {A Multi-Functional Microelectrode Array Featuring 59760 Electrodes, 2048 Electrophysiology Channels, Stimulation, Impedance Measurement and Neurotransmitter Detection Channels}, author = {Jelena Dragas and Vijay Viswam and Amir Shadmani and Yihui Chen and Raziyeh Bounik and Alexander Stettler and Milos Radivojevic and Sydney Geissler and Marie Engelene J Obien and Jan Müller and Andreas Hierlemann}, url = {http://ieeexplore.ieee.org/document/7913669/}, doi = {10.1109/JSSC.2017.2686580}, issn = {0018-9200}, year = {2017}, date = {2017-04-27}, journal = {IEEE journal of solid-state circuits}, volume = {52}, number = {6}, pages = {1576-1590}, abstract = {Biological cells are characterized by highly complex phenomena and processes that are, to a great extent, interdependent. To gain detailed insights, devices designed to study cellular phenomena need to enable tracking and manipulation of multiple cell parameters in parallel; they have to provide high signal quality and high spatiotemporal resolution. To this end, we have developed a CMOS-based microelectrode array system that integrates six measurement and stimulation functions, the largest number to date. Moreover, the system features the largest active electrode array area to date (4.48×2.43 mm(2)) to accommodate 59,760 electrodes, while its power consumption, noise characteristics, and spatial resolution (13.5 mum electrode pitch) are comparable to the best state-of-the-art devices. The system includes: 2,048 action-potential (AP, bandwidth: 300 Hz to 10 kHz) recording units, 32 local-field-potential (LFP, bandwidth: 1 Hz to 300 Hz) recording units, 32 current recording units, 32 impedance measurement units, and 28 neurotransmitter detection units, in addition to the 16 dual-mode voltage-only or current/voltage-controlled stimulation units. The electrode array architecture is based on a switch matrix, which allows for connecting any measurement/stimulation unit to any electrode in the array and for performing different measurement/stimulation functions in parallel.}, keywords = {ETH-CMOS-MEA, MEA Technology}, pubstate = {published}, tppubtype = {article} } Close Biological cells are characterized by highly complex phenomena and processes that are, to a great extent, interdependent. To gain detailed insights, devices designed to study cellular phenomena need to enable tracking and manipulation of multiple cell parameters in parallel; they have to provide high signal quality and high spatiotemporal resolution. To this end, we have developed a CMOS-based microelectrode array system that integrates six measurement and stimulation functions, the largest number to date. Moreover, the system features the largest active electrode array area to date (4.48×2.43 mm(2)) to accommodate 59,760 electrodes, while its power consumption, noise characteristics, and spatial resolution (13.5 mum electrode pitch) are comparable to the best state-of-the-art devices. The system includes: 2,048 action-potential (AP, bandwidth: 300 Hz to 10 kHz) recording units, 32 local-field-potential (LFP, bandwidth: 1 Hz to 300 Hz) recording units, 32 current recording units, 32 impedance measurement units, and 28 neurotransmitter detection units, in addition to the 16 dual-mode voltage-only or current/voltage-controlled stimulation units. The electrode array architecture is based on a switch matrix, which allows for connecting any measurement/stimulation unit to any electrode in the array and for performing different measurement/stimulation functions in parallel. Close http://ieeexplore.ieee.org/document/7913669/ doi:10.1109/JSSC.2017.2686580 Close
	Jäckel, David; Bakkum, Douglas J; Russell, Thomas L; Müller, Jan; Radivojevic, Milos; Frey, Urs; Franke, Felix; Hierlemann, Andreas Combination of High-density Microelectrode Array and Patch Clamp Recordings to Enable Studies of Multisynaptic Integration Journal Article Scientific Reports, 7 (1), pp. 978, 2017, ISSN: 2045-2322. Abstract \| Links \| BibTeX \| タグ: ETH-CMOS-MEA, Neuronal Networks @article{Jackel2017, title = {Combination of High-density Microelectrode Array and Patch Clamp Recordings to Enable Studies of Multisynaptic Integration}, author = {David Jäckel and Douglas J Bakkum and Thomas L Russell and Jan Müller and Milos Radivojevic and Urs Frey and Felix Franke and Andreas Hierlemann}, url = {http://www.nature.com/articles/s41598-017-00981-4}, doi = {10.1038/s41598-017-00981-4}, issn = {2045-2322}, year = {2017}, date = {2017-04-20}, journal = {Scientific Reports}, volume = {7}, number = {1}, pages = {978}, abstract = {We present a novel, all-electric approach to record and to precisely control the activity of tens of individual presynaptic neurons. The method allows for parallel mapping of the efficacy of multiple synapses and of the resulting dynamics of postsynaptic neurons in a cortical culture. For the measurements, we combine an extracellular high-density microelectrode array, featuring 11'000 electrodes for extracellular recording and stimulation, with intracellular patch-clamp recording. We are able to identify the contributions of individual presynaptic neurons - including inhibitory and excitatory synaptic inputs - to postsynaptic potentials, which enables us to study dendritic integration. Since the electrical stimuli can be controlled at microsecond resolution, our method enables to evoke action potentials at tens of presynaptic cells in precisely orchestrated sequences of high reliability and minimum jitter. We demonstrate the potential of this method by evoking short- and long-term synaptic plasticity through manipulation of multiple synaptic inputs to a specific neuron.}, keywords = {ETH-CMOS-MEA, Neuronal Networks}, pubstate = {published}, tppubtype = {article} } Close We present a novel, all-electric approach to record and to precisely control the activity of tens of individual presynaptic neurons. The method allows for parallel mapping of the efficacy of multiple synapses and of the resulting dynamics of postsynaptic neurons in a cortical culture. For the measurements, we combine an extracellular high-density microelectrode array, featuring 11'000 electrodes for extracellular recording and stimulation, with intracellular patch-clamp recording. We are able to identify the contributions of individual presynaptic neurons - including inhibitory and excitatory synaptic inputs - to postsynaptic potentials, which enables us to study dendritic integration. Since the electrical stimuli can be controlled at microsecond resolution, our method enables to evoke action potentials at tens of presynaptic cells in precisely orchestrated sequences of high reliability and minimum jitter. We demonstrate the potential of this method by evoking short- and long-term synaptic plasticity through manipulation of multiple synaptic inputs to a specific neuron. Close http://www.nature.com/articles/s41598-017-00981-4 doi:10.1038/s41598-017-00981-4 Close
	Seichepine, Florent; Rothe, Jorg; Dudina, Alexandra; Hierlemann, Andreas; Frey, Urs Dielectrophoresis‐Assisted Integration of 1024 Carbon Nanotube Sensors into a CMOS Microsystem Journal Article Advanced Materials, 29 (17), 2017. Abstract \| Links \| BibTeX \| タグ: ETH-CMOS-MEA @article{Seichepine2017, title = {Dielectrophoresis‐Assisted Integration of 1024 Carbon Nanotube Sensors into a CMOS Microsystem}, author = {Florent Seichepine and Jorg Rothe and Alexandra Dudina and Andreas Hierlemann and Urs Frey}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adma.201606852}, doi = {10.1002/adma.201606852}, year = {2017}, date = {2017-03-15}, journal = {Advanced Materials}, volume = {29}, number = {17}, abstract = {Carbon‐nanotube (CNT)‐based sensors offer the potential to detect single‐molecule events and picomolar analyte concentrations. An important step toward applications of such nanosensors is their integration in large arrays. The availability of large arrays would enable multiplexed and parallel sensing, and the simultaneously obtained sensor signals would facilitate statistical analysis. A reliable method to fabricate an array of 1024 CNT‐based sensors on a fully processed complementary‐metal‐oxide‐semiconductor microsystem is presented. A high‐yield process for the deposition of CNTs from a suspension by means of liquid‐coupled floating‐electrode dielectrophoresis (DEP), which yielded 80% of the sensor devices featuring between one and five CNTs, is developed. The mechanism of floating‐electrode DEP on full arrays and individual devices to understand its self‐limiting behavior is studied. The resistance distributions across the array of CNT devices with respect to different DEP parameters are characterized. The CNT devices are then operated as liquid‐gated CNT field‐effect‐transistors (LG‐CNTFET) in liquid environment. Current dependency to the gate voltage of up to two orders of magnitude is recorded. Finally, the sensors are validated by studying the pH dependency of the LG‐CNTFET conductance and it is demonstrated that 73% of the CNT sensors of a given microsystem show a resistance decrease upon increasing the pH value.}, keywords = {ETH-CMOS-MEA}, pubstate = {published}, tppubtype = {article} } Close Carbon‐nanotube (CNT)‐based sensors offer the potential to detect single‐molecule events and picomolar analyte concentrations. An important step toward applications of such nanosensors is their integration in large arrays. The availability of large arrays would enable multiplexed and parallel sensing, and the simultaneously obtained sensor signals would facilitate statistical analysis. A reliable method to fabricate an array of 1024 CNT‐based sensors on a fully processed complementary‐metal‐oxide‐semiconductor microsystem is presented. A high‐yield process for the deposition of CNTs from a suspension by means of liquid‐coupled floating‐electrode dielectrophoresis (DEP), which yielded 80% of the sensor devices featuring between one and five CNTs, is developed. The mechanism of floating‐electrode DEP on full arrays and individual devices to understand its self‐limiting behavior is studied. The resistance distributions across the array of CNT devices with respect to different DEP parameters are characterized. The CNT devices are then operated as liquid‐gated CNT field‐effect‐transistors (LG‐CNTFET) in liquid environment. Current dependency to the gate voltage of up to two orders of magnitude is recorded. Finally, the sensors are validated by studying the pH dependency of the LG‐CNTFET conductance and it is demonstrated that 73% of the CNT sensors of a given microsystem show a resistance decrease upon increasing the pH value. Close https://onlinelibrary.wiley.com/doi/abs/10.1002/adma.201606852 doi:10.1002/adma.201606852 Close
	Yada, Yuichiro; Mita, Takeshi; Sanada, Akihiro; Yano, Ryuichi; Kanzaki, Ryohei; Bakkum, Douglas J; Hierlemann, Andreas; Takahashi, Hirokazu Development of neural population activity toward self-organized criticality Journal Article Neuroscience, 343 , pp. 55-65, 2017, ISSN: 0306-4522. Abstract \| Links \| BibTeX \| タグ: ETH-CMOS-MEA, Neuronal Networks @article{Takahashi2017, title = {Development of neural population activity toward self-organized criticality}, author = {Yuichiro Yada and Takeshi Mita and Akihiro Sanada and Ryuichi Yano and Ryohei Kanzaki and Douglas J Bakkum and Andreas Hierlemann and Hirokazu Takahashi}, url = {http://www.sciencedirect.com/science/article/pii/S0306452216306522}, doi = {10.1016/j.neuroscience.2016.11.031}, issn = {0306-4522}, year = {2017}, date = {2017-02-20}, journal = {Neuroscience}, volume = {343}, pages = {55-65}, abstract = {Self-organized criticality (SoC), a spontaneous dynamic state established and maintained in networks of moderate complexity, is a universal characteristic of neural systems. Such systems produce cascades of spontaneous activity that are typically characterized by power-law distributions and rich, stable spatiotemporal patterns (i.e., neuronal avalanches). Since the dynamics of the critical state confer advantages in information processing within neuronal networks, it is of great interest to determine how criticality emerges during development. One possible mechanism is developmental, and includes axonal elongation during synaptogenesis and subsequent synaptic pruning in combination with the maturation of GABAergic inhibition (i.e., the integration then fragmentation process). Because experimental evidence for this mechanism remains inconclusive, we studied the developmental variation of neuronal avalanches in dissociated cortical neurons using high-density complementary metal-oxide semiconductor (CMOS) microelectrode arrays (MEAs). The spontaneous activities of nine cultures were monitored using CMOS MEAs from 4 to 30 days in vitro (DIV) at single-cell spatial resolution. While cells were immature, cultures demonstrated random-like patterns of activity and an exponential avalanche size distribution; this distribution was followed by a bimodal distribution, and finally a power-law-like distribution. The bimodal distribution was associated with a large-scale avalanche with a homogeneous spatiotemporal pattern, while the subsequent power-law distribution was associated with diverse patterns. These results suggest that the SoC emerges through a two-step process: the integration process accompanying the characteristic large-scale avalanche and the fragmentation process associated with diverse middle-size avalanches.}, keywords = {ETH-CMOS-MEA, Neuronal Networks}, pubstate = {published}, tppubtype = {article} } Close Self-organized criticality (SoC), a spontaneous dynamic state established and maintained in networks of moderate complexity, is a universal characteristic of neural systems. Such systems produce cascades of spontaneous activity that are typically characterized by power-law distributions and rich, stable spatiotemporal patterns (i.e., neuronal avalanches). Since the dynamics of the critical state confer advantages in information processing within neuronal networks, it is of great interest to determine how criticality emerges during development. One possible mechanism is developmental, and includes axonal elongation during synaptogenesis and subsequent synaptic pruning in combination with the maturation of GABAergic inhibition (i.e., the integration then fragmentation process). Because experimental evidence for this mechanism remains inconclusive, we studied the developmental variation of neuronal avalanches in dissociated cortical neurons using high-density complementary metal-oxide semiconductor (CMOS) microelectrode arrays (MEAs). The spontaneous activities of nine cultures were monitored using CMOS MEAs from 4 to 30 days in vitro (DIV) at single-cell spatial resolution. While cells were immature, cultures demonstrated random-like patterns of activity and an exponential avalanche size distribution; this distribution was followed by a bimodal distribution, and finally a power-law-like distribution. The bimodal distribution was associated with a large-scale avalanche with a homogeneous spatiotemporal pattern, while the subsequent power-law distribution was associated with diverse patterns. These results suggest that the SoC emerges through a two-step process: the integration process accompanying the characteristic large-scale avalanche and the fragmentation process associated with diverse middle-size avalanches. Close http://www.sciencedirect.com/science/article/pii/S0306452216306522 doi:10.1016/j.neuroscience.2016.11.031 Close
2016
	Gong, Wei; Sencar, Jure; Bakkum, Douglas J; Jäckel, David; Obien, Marie Engelene J; Radivojevic, Milos; Hierlemann, Andreas Multiple single-unit long-term tracking on organotypic hippocampal slices using high-density microelectrode arrays Journal Article Frontiers in Neuroscience, 10 , pp. 1-16, 2016, ISSN: 1662453X. Abstract \| Links \| BibTeX \| タグ: Brain Slice, ETH-CMOS-MEA @article{Gong2016, title = {Multiple single-unit long-term tracking on organotypic hippocampal slices using high-density microelectrode arrays}, author = {Wei Gong and Jure Sencar and Douglas J Bakkum and David Jäckel and Marie Engelene J Obien and Milos Radivojevic and Andreas Hierlemann}, url = {https://www.frontiersin.org/articles/10.3389/fnins.2016.00537/full}, doi = {10.3389/fnins.2016.00537}, issn = {1662453X}, year = {2016}, date = {2016-11-22}, journal = {Frontiers in Neuroscience}, volume = {10}, pages = {1-16}, abstract = {A novel system to cultivate and record from organotypic brain slices directly on high-density microelectrode arrays (HD-MEA) was developed. This system allows for continuous recording of electrical activity of specific individual neurons at high spatial resolution while monitoring at the same time, neuronal network activity. For the first time, the electrical activity patterns of single neurons and the corresponding neuronal network in an organotypic hippocampal slice culture were studied during several consecutive weeks at daily intervals. An unsupervised iterative spike-sorting algorithm, based on PCA and k-means clustering, was developed to assign the activities to the single units. Spike-triggered average extracellular waveforms of an action potential recorded across neighboring electrodes, termed ‘footprints' of single-units were generated and tracked over weeks. The developed system offers the potential to study chronic impacts of drugs or genetic modifications on individual neurons in slice preparations over extended times.}, keywords = {Brain Slice, ETH-CMOS-MEA}, pubstate = {published}, tppubtype = {article} } Close A novel system to cultivate and record from organotypic brain slices directly on high-density microelectrode arrays (HD-MEA) was developed. This system allows for continuous recording of electrical activity of specific individual neurons at high spatial resolution while monitoring at the same time, neuronal network activity. For the first time, the electrical activity patterns of single neurons and the corresponding neuronal network in an organotypic hippocampal slice culture were studied during several consecutive weeks at daily intervals. An unsupervised iterative spike-sorting algorithm, based on PCA and k-means clustering, was developed to assign the activities to the single units. Spike-triggered average extracellular waveforms of an action potential recorded across neighboring electrodes, termed ‘footprints' of single-units were generated and tracked over weeks. The developed system offers the potential to study chronic impacts of drugs or genetic modifications on individual neurons in slice preparations over extended times. Close https://www.frontiersin.org/articles/10.3389/fnins.2016.00537/full doi:10.3389/fnins.2016.00537 Close
	Deligkaris, Kosmas; Bullmann, Torsten; Frey, Urs Extracellularly Recorded Somatic and Neuritic Signal Shapes and Classification Algorithms for High-Density Microelectrode Array Electrophysiology Journal Article Frontiers in Neuroscience, 10 , pp. 421, 2016, ISSN: 1662-453X. Abstract \| Links \| BibTeX \| タグ: ETH-CMOS-MEA, Neuronal Networks @article{Frey2016, title = {Extracellularly Recorded Somatic and Neuritic Signal Shapes and Classification Algorithms for High-Density Microelectrode Array Electrophysiology}, author = {Kosmas Deligkaris and Torsten Bullmann and Urs Frey}, url = {https://www.frontiersin.org/article/10.3389/fnins.2016.00421}, doi = {10.3389/fnins.2016.00421}, issn = {1662-453X}, year = {2016}, date = {2016-09-14}, journal = {Frontiers in Neuroscience}, volume = {10}, pages = {421}, abstract = {High-density microelectrode arrays (HDMEA) have been recently introduced to study principles of neural function at high spatial resolution. However, the exact nature of the experimentally observed extracellular action potentials (EAPs) is still incompletely understood. The soma, axon and dendrites of a neuron can all exhibit regenerative action potentials that could be sensed with HDMEA electrodes. Here, we investigate the contribution of distinct neuronal sources of activity in HDMEA recordings from low-density neuronal cultures. We recorded EAPs with HDMEAs having 11,011 electrodes and then fixed and immunostained the cultures with beta3-tubulin for high-resolution fluorescence imaging. Immunofluorescence images overlaid with the activity maps showed EAPs both at neuronal somata and distal neurites. Neuritic EAPs had mostly narrow triphasic shapes, consisting of a positive, a pronounced negative peak and a second positive peak. EAPs near somata had wide monophasic or biphasic shapes with a main negative peak, and following optional positive peak. We show that about 86% of EAP recordings consist of somatic spikes, while the remaining 14% represent neuritic spikes. Furthermore, the adaptation of the waveform shape during bursts of these neuritic spikes suggested that they originate from axons, rather than from dendrites. Our study improves the understanding of HDMEA signals and can aid in the identification of the source of EAPs.}, keywords = {ETH-CMOS-MEA, Neuronal Networks}, pubstate = {published}, tppubtype = {article} } Close High-density microelectrode arrays (HDMEA) have been recently introduced to study principles of neural function at high spatial resolution. However, the exact nature of the experimentally observed extracellular action potentials (EAPs) is still incompletely understood. The soma, axon and dendrites of a neuron can all exhibit regenerative action potentials that could be sensed with HDMEA electrodes. Here, we investigate the contribution of distinct neuronal sources of activity in HDMEA recordings from low-density neuronal cultures. We recorded EAPs with HDMEAs having 11,011 electrodes and then fixed and immunostained the cultures with beta3-tubulin for high-resolution fluorescence imaging. Immunofluorescence images overlaid with the activity maps showed EAPs both at neuronal somata and distal neurites. Neuritic EAPs had mostly narrow triphasic shapes, consisting of a positive, a pronounced negative peak and a second positive peak. EAPs near somata had wide monophasic or biphasic shapes with a main negative peak, and following optional positive peak. We show that about 86% of EAP recordings consist of somatic spikes, while the remaining 14% represent neuritic spikes. Furthermore, the adaptation of the waveform shape during bursts of these neuritic spikes suggested that they originate from axons, rather than from dendrites. Our study improves the understanding of HDMEA signals and can aid in the identification of the source of EAPs. Close https://www.frontiersin.org/article/10.3389/fnins.2016.00421 doi:10.3389/fnins.2016.00421 Close
	Radivojevic, Milos; Jäckel, David; Altermatt, Michael; Müller, Jan; Viswam, Vijay; Hierlemann, Andreas; Bakkum, Douglas J Electrical Identification and Selective Microstimulation of Neuronal Compartments Based on Features of Extracellular Action Potentials Journal Article Scientific Reports, 6 (1), pp. 1-20, 2016, ISSN: 2045-2322. Abstract \| Links \| BibTeX \| タグ: ETH-CMOS-MEA, Neuronal Networks, Stimulation @article{Radivojevic2016, title = {Electrical Identification and Selective Microstimulation of Neuronal Compartments Based on Features of Extracellular Action Potentials}, author = {Milos Radivojevic and David Jäckel and Michael Altermatt and Jan Müller and Vijay Viswam and Andreas Hierlemann and Douglas J Bakkum}, url = {http://www.nature.com/articles/srep31332}, doi = {10.1038/srep31332}, issn = {2045-2322}, year = {2016}, date = {2016-08-11}, journal = {Scientific Reports}, volume = {6}, number = {1}, pages = {1-20}, abstract = {A detailed, high-spatiotemporal-resolution characterization of neuronal responses to local electrical fields and the capability of precise extracellular microstimulation of selected neurons are pivotal for studying and manipulating neuronal activity and circuits in networks and for developing neural prosthetics. Here, we studied cultured neocortical neurons by using high-density microelectrode arrays and optical imaging, complemented by the patch-clamp technique, and with the aim to correlate morphological and electrical features of neuronal compartments with their responsiveness to extracellular stimulation. We developed strategies to electrically identify any neuron in the network, while subcellular spatial resolution recording of extracellular action potential (AP) traces enabled their assignment to the axon initial segment (AIS), axonal arbor and proximal somatodendritic compartments. Stimulation at the AIS required low voltages and provided immediate, selective and reliable neuronal activation, whereas stimulation at the soma required high voltages and produced delayed and unreliable responses. Subthreshold stimulation at the soma depolarized the somatic membrane potential without eliciting APs.}, keywords = {ETH-CMOS-MEA, Neuronal Networks, Stimulation}, pubstate = {published}, tppubtype = {article} } Close A detailed, high-spatiotemporal-resolution characterization of neuronal responses to local electrical fields and the capability of precise extracellular microstimulation of selected neurons are pivotal for studying and manipulating neuronal activity and circuits in networks and for developing neural prosthetics. Here, we studied cultured neocortical neurons by using high-density microelectrode arrays and optical imaging, complemented by the patch-clamp technique, and with the aim to correlate morphological and electrical features of neuronal compartments with their responsiveness to extracellular stimulation. We developed strategies to electrically identify any neuron in the network, while subcellular spatial resolution recording of extracellular action potential (AP) traces enabled their assignment to the axon initial segment (AIS), axonal arbor and proximal somatodendritic compartments. Stimulation at the AIS required low voltages and provided immediate, selective and reliable neuronal activation, whereas stimulation at the soma required high voltages and produced delayed and unreliable responses. Subthreshold stimulation at the soma depolarized the somatic membrane potential without eliciting APs. Close http://www.nature.com/articles/srep31332 doi:10.1038/srep31332 Close
	Lewandowska, Marta K; Radivojevic, Milos; Jäckel, David; Müller, Jan; Hierlemann, Andreas Cortical axons, isolated in channels, display activity-dependent signal modulation as a result of targeted stimulation Journal Article Frontiers in Neuroscience, 10 , pp. 83, 2016, ISSN: 1662453X. Abstract \| Links \| BibTeX \| タグ: MaxOne, Neuronal Networks, u-Tunnels @article{Lewandowska2016, title = {Cortical axons, isolated in channels, display activity-dependent signal modulation as a result of targeted stimulation}, author = {Marta K Lewandowska and Milos Radivojevic and David Jäckel and Jan Müller and Andreas Hierlemann}, url = {https://www.frontiersin.org/articles/10.3389/fnins.2016.00083/full}, doi = {10.3389/fnins.2016.00083}, issn = {1662453X}, year = {2016}, date = {2016-03-07}, journal = {Frontiers in Neuroscience}, volume = {10}, pages = {83}, abstract = {Mammalian cortical axons are extremely thin processes that are difficult to study as a result of their small diameter: they are too narrow to patch while intact, and super-resolution microscopy is needed to resolve single axons. We present a method for studying axonal physiology by pairing a high-density microelectrode array with a microfluidic axonal isolation device, and use it to study activity-dependent modulation of axonal signal propagation evoked by stimulation near the soma. Up to three axonal branches from a single neuron, isolated in different channels, were recorded from simultaneously using 10-20 electrodes per channel. The axonal channels amplified spikes such that propagations of individual signals along tens of electrodes could easily be discerned with high signal to noise. Stimulation from 10 up to 160 Hz demonstrated similar qualitative results from all of the cells studied: extracellular action potential characteristics changed drastically in response to stimulation. Spike height decreased, spike width increased, and latency increased, as a result of reduced propagation velocity, as the number of stimulations and the stimulation frequencies increased. Quantitatively, the strength of these changes manifested itself differently in cells at different frequencies of stimulation. Some cells' signal fidelity fell to 80% already at 10 Hz, while others maintained 80% signal fidelity at 80 Hz. Differences in modulation by axonal branches of the same cell were also seen for different stimulation frequencies, starting at 10 Hz. Potassium ion concentration changes altered the behavior of the cells causing propagation failures at lower concentrations and improving signal fidelity at higher concentrations.}, keywords = {MaxOne, Neuronal Networks, u-Tunnels}, pubstate = {published}, tppubtype = {article} } Close Mammalian cortical axons are extremely thin processes that are difficult to study as a result of their small diameter: they are too narrow to patch while intact, and super-resolution microscopy is needed to resolve single axons. We present a method for studying axonal physiology by pairing a high-density microelectrode array with a microfluidic axonal isolation device, and use it to study activity-dependent modulation of axonal signal propagation evoked by stimulation near the soma. Up to three axonal branches from a single neuron, isolated in different channels, were recorded from simultaneously using 10-20 electrodes per channel. The axonal channels amplified spikes such that propagations of individual signals along tens of electrodes could easily be discerned with high signal to noise. Stimulation from 10 up to 160 Hz demonstrated similar qualitative results from all of the cells studied: extracellular action potential characteristics changed drastically in response to stimulation. Spike height decreased, spike width increased, and latency increased, as a result of reduced propagation velocity, as the number of stimulations and the stimulation frequencies increased. Quantitatively, the strength of these changes manifested itself differently in cells at different frequencies of stimulation. Some cells' signal fidelity fell to 80% already at 10 Hz, while others maintained 80% signal fidelity at 80 Hz. Differences in modulation by axonal branches of the same cell were also seen for different stimulation frequencies, starting at 10 Hz. Potassium ion concentration changes altered the behavior of the cells causing propagation failures at lower concentrations and improving signal fidelity at higher concentrations. Close https://www.frontiersin.org/articles/10.3389/fnins.2016.00083/full doi:10.3389/fnins.2016.00083 Close
	Franke, Felix; Fiscella, Michele; Sevelev, Maksim; Roska, Botond; Hierlemann, Andreas; Azeredo da Silveira, Rava Structures of Neural Correlation and How They Favor Coding Journal Article Neuron, 89 (2), pp. 409-422, 2016, ISSN: 10974199. Abstract \| Links \| BibTeX \| タグ: Data Analysis, ETH-CMOS-MEA, Neuronal Networks, Retina @article{Franke2016, title = {Structures of Neural Correlation and How They Favor Coding}, author = {Felix Franke and Michele Fiscella and Maksim Sevelev and Botond Roska and Andreas Hierlemann and Rava {Azeredo da Silveira}}, url = {http://www.sciencedirect.com/science/article/pii/S0896627315011393?via%3Dihub}, doi = {10.1016/j.neuron.2015.12.037}, issn = {10974199}, year = {2016}, date = {2016-01-20}, journal = {Neuron}, volume = {89}, number = {2}, pages = {409-422}, publisher = {Elsevier Inc.}, abstract = {The neural representation of information suffers from "noise"-the trial-to-trial variability in the response of neurons. The impact of correlated noise upon population coding has been debated, but a direct connection between theory and experiment remains tenuous. Here, we substantiate this connection and propose a refined theoretical picture. Using simultaneous recordings from a population of direction-selective retinal ganglion cells, we demonstrate that coding benefits from noise correlations. The effect is appreciable already in small populations, yet it is a collective phenomenon. Furthermore, the stimulus-dependent structure of correlation is key. We develop simple functional models that capture the stimulus-dependent statistics. We then use them to quantify the performance of population coding, which depends upon interplays of feature sensitivities and noise correlations in the population. Because favorable structures of correlation emerge robustly in circuits with noisy, nonlinear elements, they will arise and benefit coding beyond the confines of retina. Coding in the brain suffers from the variability of neural responses. Using experiment and theory, Franke et al. show that this "noise" comes with a particular structure, which emerges from circuit properties and which counteracts the harmful effect of variability.}, keywords = {Data Analysis, ETH-CMOS-MEA, Neuronal Networks, Retina}, pubstate = {published}, tppubtype = {article} } Close The neural representation of information suffers from "noise"-the trial-to-trial variability in the response of neurons. The impact of correlated noise upon population coding has been debated, but a direct connection between theory and experiment remains tenuous. Here, we substantiate this connection and propose a refined theoretical picture. Using simultaneous recordings from a population of direction-selective retinal ganglion cells, we demonstrate that coding benefits from noise correlations. The effect is appreciable already in small populations, yet it is a collective phenomenon. Furthermore, the stimulus-dependent structure of correlation is key. We develop simple functional models that capture the stimulus-dependent statistics. We then use them to quantify the performance of population coding, which depends upon interplays of feature sensitivities and noise correlations in the population. Because favorable structures of correlation emerge robustly in circuits with noisy, nonlinear elements, they will arise and benefit coding beyond the confines of retina. Coding in the brain suffers from the variability of neural responses. Using experiment and theory, Franke et al. show that this "noise" comes with a particular structure, which emerges from circuit properties and which counteracts the harmful effect of variability. Close http://www.sciencedirect.com/science/article/pii/S0896627315011393?via%3Dihub doi:10.1016/j.neuron.2015.12.037 Close
	Yonehara, Keisuke; Fiscella, Michele; Drinnenberg, Antonia; Esposti, Federico; Trenholm, Stuart; Krol, Jacek; Franke, Felix; Scherf, Brigitte Gross; Kusnyerik, Akos; Müller, Jan; Szabo, Arnold; Jüttner, Josephine; Cordoba, Francisco; Reddy, Ashrithpal Police; Németh, János; Nagy, Zoltán Zsolt; Munier, Francis; Hierlemann, Andreas; Roska, Botond Congenital Nystagmus Gene FRMD7 Is Necessary for Establishing a Neuronal Circuit Asymmetry for Direction Selectivity Journal Article Neuron, 89 (1), pp. 177-193, 2016, ISSN: 10974199. Abstract \| Links \| BibTeX \| タグ: ETH-CMOS-MEA, Retina @article{Yonehara2016, title = {Congenital Nystagmus Gene FRMD7 Is Necessary for Establishing a Neuronal Circuit Asymmetry for Direction Selectivity}, author = {Keisuke Yonehara and Michele Fiscella and Antonia Drinnenberg and Federico Esposti and Stuart Trenholm and Jacek Krol and Felix Franke and Brigitte Gross Scherf and Akos Kusnyerik and Jan Müller and Arnold Szabo and Josephine Jüttner and Francisco Cordoba and Ashrithpal Police Reddy and János Németh and Zoltán Zsolt Nagy and Francis Munier and Andreas Hierlemann and Botond Roska}, url = {http://www.sciencedirect.com/science/article/pii/S0896627315010387?via%3Dihub}, doi = {10.1016/j.neuron.2015.11.032}, issn = {10974199}, year = {2016}, date = {2016-01-06}, journal = {Neuron}, volume = {89}, number = {1}, pages = {177-193}, abstract = {Neuronal circuit asymmetries are important components of brain circuits, but the molecular pathways leading to their establishment remain unknown. Here we found that the mutation of FRMD7, a gene that is defective in human congenital nystagmus, leads to the selective loss of the horizontal optokinetic reflex in mice, as it does in humans. This is accompanied by the selective loss of horizontal direction selectivity in retinal ganglion cells and the transition from asymmetric to symmetric inhibitory input to horizontal direction-selective ganglion cells. In wild-type retinas, we found FRMD7 specifically expressed in starburst amacrine cells, the interneuron type that provides asymmetric inhibition to direction-selective retinal ganglion cells. This work identifies FRMD7 as a key regulator in establishing a neuronal circuit asymmetry, and it suggests the involvement of a specific inhibitory neuron type in the pathophysiology of a neurological disease.}, keywords = {ETH-CMOS-MEA, Retina}, pubstate = {published}, tppubtype = {article} } Close Neuronal circuit asymmetries are important components of brain circuits, but the molecular pathways leading to their establishment remain unknown. Here we found that the mutation of FRMD7, a gene that is defective in human congenital nystagmus, leads to the selective loss of the horizontal optokinetic reflex in mice, as it does in humans. This is accompanied by the selective loss of horizontal direction selectivity in retinal ganglion cells and the transition from asymmetric to symmetric inhibitory input to horizontal direction-selective ganglion cells. In wild-type retinas, we found FRMD7 specifically expressed in starburst amacrine cells, the interneuron type that provides asymmetric inhibition to direction-selective retinal ganglion cells. This work identifies FRMD7 as a key regulator in establishing a neuronal circuit asymmetry, and it suggests the involvement of a specific inhibitory neuron type in the pathophysiology of a neurological disease. Close http://www.sciencedirect.com/science/article/pii/S0896627315010387?via%3Dihub doi:10.1016/j.neuron.2015.11.032 Close
	Viswam, Vijay; Dragas, Jelena; Shadmani, Amir; Chen, Yihui; Stettler, Alexander; Müller, Jan; Hierlemann, Andreas 22.8 Multi-functional microelectrode array system featuring 59,760 electrodes, 2048 electrophysiology channels, impedance and neurotransmitter measurement units Conference 2016 IEEE International Solid-State Circuits Conference (ISSCC), 2016. Abstract \| Links \| BibTeX \| タグ: Action Potential, ETH-CMOS-MEA, HD-MEA, MEA Technology @conference{Viswam2016, title = {22.8 Multi-functional microelectrode array system featuring 59,760 electrodes, 2048 electrophysiology channels, impedance and neurotransmitter measurement units}, author = {Vijay Viswam and Jelena Dragas and Amir Shadmani and Yihui Chen and Alexander Stettler and Jan Müller and Andreas Hierlemann}, url = {http://ieeexplore.ieee.org/document/7418073/}, doi = {10.1109/ISSCC.2016.7418073}, year = {2016}, date = {2016-01-01}, booktitle = {2016 IEEE International Solid-State Circuits Conference (ISSCC)}, journal = {2016 IEEE International Solid-State Circuits Conference (ISSCC)}, abstract = {Various CMOS-based micro-electrode arrays (MEAs) have been developed in recent years for extracellular electrophysiological recording/stimulation of electrogenic cells [1–5]. Mostly two approaches have been used: (i) the activepixel approach (APS) [2–4], which features simultaneous readout of all electrodes, however, at the expense of a comparably high noise level, and (ii) the switchmatrix (SM) approach, which yields better noise performance, whereas only a subset of electrodes (e.g.,1024) is simultaneously read out [5]. All systems feature, at most, voltage recording and/or voltage/current stimulation functionalities.}, keywords = {Action Potential, ETH-CMOS-MEA, HD-MEA, MEA Technology}, pubstate = {published}, tppubtype = {conference} } Close Various CMOS-based micro-electrode arrays (MEAs) have been developed in recent years for extracellular electrophysiological recording/stimulation of electrogenic cells [1–5]. Mostly two approaches have been used: (i) the activepixel approach (APS) [2–4], which features simultaneous readout of all electrodes, however, at the expense of a comparably high noise level, and (ii) the switchmatrix (SM) approach, which yields better noise performance, whereas only a subset of electrodes (e.g.,1024) is simultaneously read out [5]. All systems feature, at most, voltage recording and/or voltage/current stimulation functionalities. Close http://ieeexplore.ieee.org/document/7418073/ doi:10.1109/ISSCC.2016.7418073 Close
2015
	Jones, Ian L; Russell, Thomas L; Farrow, Karl; Fiscella, Michele; Franke, Felix; Müller, Jan; Jäckel, David; Hierlemann, Andreas A method for electrophysiological characterization of hamster retinal ganglion cells using a high-density CMOS microelectrode array Journal Article Frontiers in Neuroscience, 9 , pp. 360, 2015, ISSN: 1662453X. Abstract \| Links \| BibTeX \| タグ: ETH-CMOS-MEA, Retina @article{Jones2015, title = {A method for electrophysiological characterization of hamster retinal ganglion cells using a high-density CMOS microelectrode array}, author = {Ian L Jones and Thomas L Russell and Karl Farrow and Michele Fiscella and Felix Franke and Jan Müller and David Jäckel and Andreas Hierlemann}, url = {https://www.frontiersin.org/articles/10.3389/fnins.2015.00360/full}, doi = {10.3389/fnins.2015.00360}, issn = {1662453X}, year = {2015}, date = {2015-10-13}, journal = {Frontiers in Neuroscience}, volume = {9}, pages = {360}, abstract = {Knowledge of neuronal cell types in the mammalian retina is important for the understanding of human retinal disease and the advancement of sight-restoring technology, such as retinal prosthetic devices. A somewhat less utilized animal model for retinal research is the hamster, which has a visual system that is characterized by an area centralis and a wide visual field with a broad binocular component. The hamster retina is optimally suited for recording on the microelectrode array (MEA), because it intrinsically lies flat on the MEA surface and yields robust, large-amplitude signals. However, information in the literature about hamster retinal ganglion cell functional types is scarce. The goal of our work is to develop a method featuring a high-density (HD) Complementary metal-oxide-semiconductor (CMOS) MEA technology along with a sequence of standardized visual stimuli in order to categorize ganglion cells in isolated Syrian Hamster (Mesocricetus auratus) retina. Since the HD-MEA is capable of recording at a higher spatial resolution than most MEA systems (17.5 um electrode pitch), we capitalized on this feature and were able to record from a large proportion of RGCs within a selected region. Secondly, we chose our stimuli so that they could be run during the experiment without intervention or computation steps. The visual stimulus set was designed to activate the receptive fields of most ganglion cells in parallel and to incorporate various visual features to which different cell types respond uniquely. Based on the ganglion cell responses, basic cell properties were determined: direction selectivity, speed tuning, width tuning, transience and latency. These properties were clustered in order to identify ganglion cell types in the hamster retina. Ultimately, we recorded up to a cell density 2780 cells/mm2 at 2 mm (42°) from the optic nerve head. Using 5 parameters extracted from the responses to visual stimuli, we obtained 7 ganglion cell types.}, keywords = {ETH-CMOS-MEA, Retina}, pubstate = {published}, tppubtype = {article} } Close Knowledge of neuronal cell types in the mammalian retina is important for the understanding of human retinal disease and the advancement of sight-restoring technology, such as retinal prosthetic devices. A somewhat less utilized animal model for retinal research is the hamster, which has a visual system that is characterized by an area centralis and a wide visual field with a broad binocular component. The hamster retina is optimally suited for recording on the microelectrode array (MEA), because it intrinsically lies flat on the MEA surface and yields robust, large-amplitude signals. However, information in the literature about hamster retinal ganglion cell functional types is scarce. The goal of our work is to develop a method featuring a high-density (HD) Complementary metal-oxide-semiconductor (CMOS) MEA technology along with a sequence of standardized visual stimuli in order to categorize ganglion cells in isolated Syrian Hamster (Mesocricetus auratus) retina. Since the HD-MEA is capable of recording at a higher spatial resolution than most MEA systems (17.5 um electrode pitch), we capitalized on this feature and were able to record from a large proportion of RGCs within a selected region. Secondly, we chose our stimuli so that they could be run during the experiment without intervention or computation steps. The visual stimulus set was designed to activate the receptive fields of most ganglion cells in parallel and to incorporate various visual features to which different cell types respond uniquely. Based on the ganglion cell responses, basic cell properties were determined: direction selectivity, speed tuning, width tuning, transience and latency. These properties were clustered in order to identify ganglion cell types in the hamster retina. Ultimately, we recorded up to a cell density 2780 cells/mm2 at 2 mm (42°) from the optic nerve head. Using 5 parameters extracted from the responses to visual stimuli, we obtained 7 ganglion cell types. Close https://www.frontiersin.org/articles/10.3389/fnins.2015.00360/full doi:10.3389/fnins.2015.00360 Close

論文

Publications

Selected Publications

<img decoding="async" class="floatLeft aligncenter" src="https://www.mxwbio.com/wp-content/uploads/2016/06/Mueller2015.jpg" alt="Mueller2015" width="200" /> High-resolution CMOS MEA platform to study neurons at subcellular, cellular, and network levels

<img decoding="async" class="floatLeft aligncenter" src="https://www.mxwbio.com/wp-content/uploads/2016/06/Obien2014frontiersrev.jpg" alt="Obien2014" width="200" /> Revealing Neuronal Function through Microelectrode Array Recordings

A 1024-Channel CMOS Microelectrode Array With 26,400 Electrodes for Recording and Stimulation of Electrogenic Cells In Vitro

Tracking axonal action potential propagation on a high-density microelectrode array across hundreds of sites

Microelectronic System for High-Resolution Mapping of Extracellular Electric Fields Applied to Brain Slices

Modulation of Cardiomyocyte Electrical Properties Using Regulated Bone Morphogenetic Protein-2 Expression

All Publications

2019

2018

2017

2016

2015

High-resolution CMOS MEA platform to study neurons at subcellular, cellular, and network levels

Revealing Neuronal Function through Microelectrode Array Recordings