Noninvasive neuroelectronic interfacing with synaptically connected snail neurons immobilized on a semiconductor chip

A hybrid circuit of a semiconductor chip and synaptically connected neurons was implemented and characterized, Individual nerve cells from the snail L ymnaea stagnalis were immobilized on a silicon chip by microscopic picket f ences of polyimide. The cells formed a network with electrical synapses aft er outgrowth in brain conditioned medium. Pairs of neurons were electronica lly interfaced for noninvasive stimulation and recording. Voltage pulses we re applied to a capacitive stimulator on the chip to excite the attached ne uron. Signals were transmitted in the neuronal net and elicited an action p otential in a second neuron. The postsynaptic excitation modulated the curr ent of a transistor on the chip. The implementation of the silicon-neuron-n euron-silicon circuit constitutes a proof-of-principle experiment for the d evelopment of neuroelectronic systems to be used in studies on neuronal sig nal processing, neurocomputation, and neuroprosthetics.