Enhanced Response to Subthreshold Signals by Phase Noise in a Hodgkin-Huxley Neuron

Noise has been revealed as an important cue for understanding the extraordinary ability of sensory neurons to detect or amplify external weak signals. We demonstrate that phase noise originating from the time-varying signal phase can enable an excitable neuron to excite spikes upon a periodic signal even though the signal amplitude is subthreshold. In addition, we find that there exists an optimal value on the phase noise at which the neuron's response to the subthreshold periodic signal can be significantly improved, resulting in a resonance-like behavior. Since phase noise makes the external signal aperiodic, our findings show that sensory neurons might evolve with a better performance on detecting aperiodic signals than periodic signals.