Coherence resonance in an autaptic Hodgkin–Huxley neuron with time delay

Autapses, synapses between a neuron and itself, are believed to serve as a regulator of information processing in the nervous system. Noise, as random or unpredictable fluctuations, affects nearly all aspects of nervous function. In this work, we studied the regulatory ability of an autapse on firing behaviors of a Hodgkin–Huxley neuron in response to synaptic-like signals in the presence of noise. For weak subthreshold synaptic input, the autaptic neuron produced the similar firing behavior governed by the noise in case of either determinate or random synaptic input. The critical noise intensity necessary to trigger the spike train slightly was decreased with determinate low-frequency input. Under a strong suprathreshold synaptic current, noise-induced frequency resonance and precise responses mostly occured with a high-frequency determinate input. With a random strong synaptic input, an increase in the autaptic delay led to a resonance-like response, but had no observable effects in cases with a short delay time under a low-frequency input.