Regular pulsing induced by noise in a monolithic semiconductor neuron

We report on the stochastic dynamics of a semiconductor neuron that uses the non-linear conductances of modulation doped semiconductors to compute electrical spikes. This GaAs-based neuron has pn wires which propagate and delay electrical pulses and a soma which sums and regenerates pulses through the positive feedback of a quantum tunnel amplifier vertically integrated with the wire. The neuron exhibits the property of excitability: it responds with a spike to a perturbation that exceeds a certain threshold value, and remains silent if the perturbation is small. When exciting the neuron with a sub-threshold periodic signal, a superimposed random noise is shown to enhance the coherence of the output pulse train. We perform a systematic study of stochastic resonance and coherence resonance as a function of excitation parameters and analyze output spectra using statistical tools.