Interfacing neurons and silicon by electrical induction

Direct electrical coupling of a nerve cell and silicon microstructures is achieved by electrical induction without electrochemical current across the silicon/electrolyte interface. A field-effect transistor with an insulated open gate detects the action potential of an attached neuron. A voltage step applied to a silicon microelectrode elicits an action potential through an insulating film of silicon dioxide. The electrical aspects of the neuron-silicon junctions are described by a representative circuit. its capacitive and resistive components are determined by AC-signals using patch-clamp technique. A spatially resolved picture of a junction is obtained by placing an array of closely packed transistors beneath a single neuron. The cable theory is used to describe the extended region of adhesion. Aspects of a further development of the systems and of their application are considered.