Coherence resonance with multiple peaks in a coupled FitzHugh-Nagumo model

Coherence resonance in a coupled excitable system is studied, through both a computer simulation and a circuit experiment, using a piecewise linear version of the FitzHugh-Nagumo model. White noise is added to the first element and spikes are accordingly generated and transmitted to the second element. The mean, standard deviation, and coefficient of variation of the interspike intervals in the second element have multiple peaks as the noise strengthens, when the coupling strength is small. This results from the phase locking to the spikes that the noise generates.