Noise effects on spike propagation during the refractory period in the FitzHugh-Nagumo model

Effects of membrane noise on spike propagation on a nerve fiber are studied on the basis of a stochastic version of the FitzHugh-Nagumo model. The noise varies the propagation speeds of spikes and thus changes the interspike intervals of a spike train during propagation. A kinematic description of spike propagation derives expressions for the changes in the interspike intervals. It is shown that the dispersion relation causes the correlation of the interspike intervals characteristic of a spike train propagating in the refractory period.