A bio-physically inspired silicon neuron

The physical principles governing ion flow in biological neurons share interesting similarities to electron flow through the channels of MOSFET transistors. Here, is described a circuit which exploits the similarities better than previous approaches to build an elegant circuit with electrical properties similar to real biological neurons. A two-channel model is discussed including sodium (Na⁺) and potassium (K⁺). The Na⁺ channel uses four transistors and two capacitors. The K⁺ channel uses two transistors and one capacitor. One more capacitor simulates the neuron membrane capacitance yielding a total circuit of four capacitors and six transistors. This circuit operates in real-time, is fabricated on standard CMOS processes, runs in subthreshold, and has a power supply similar to that of real biology. Voltage and current responses of this circuit correspond well with biology in terms of shape, magnitude, and time.