Circuit implementation of neural FitzHugh-Nagumo equations

摘要

A circuit that emulates FitzHugh-Nagumo's differential equations using OTAs, diodes, and capacitors is proposed. These equations model the fundamental behavior of an organic neuron cell, i.e. if the input is below a certain threshold, no output is observed, and if it is above threshold, the output yields a sequence of firing pulses. The circuit is obtained by using a general method for implementing nonlinear differential equations. The resulting circuit, due to the (voltage) programmability of the OTA, allows one to easily vary parameters. Thus, a large family of solutions can be obtained, including the Van der Pol's equation. Experimental results from a breadboard prototype that show the suitability of the technique and its potential for CMOS implementation are given.