A circuit was developed to serve as an interface from an intact biological neuron to an electromechanical device. The circuit is a custom VLSI IC that contains a highly sensitive buffer, a neuron-like threshold discriminator, and a dedicated four-phase output driver. Nerve-like in behavior, the circuit detects action potentials from living nerve tissue, and if the activity exceeds a given threshold, drives a four-phase stepper motor. Fabricated in 2-micron CMOS, the circuit is comprehensive, compact, noise-immune, and very power efficient, making it appropriate for the control of robotic or prosthetic devices.<<ETX>>