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.