Noise-induced Phenomena in Two Strongly Pulse-coupled Spiking Neurons

In this study, we address noise-induced phenomena in a system of two pulse-coupled resonate-and-fire neuron models as a piecewise smooth dynamical system. The model is a spiking neuron model that has second-order membrane dynamics with a firing threshold, and it exhibits subthreshold oscillation of membrane potential, resulting in the sensitivity to the timing of inputs. The pulse-coupled system shows the grazing bifurcation, a specific feature of a piecewise smooth dynamical system, as well as the saddle-node bifurcation. We numerically investigated mixture bifurcation structure of the system, leading to complex behaviors, such as burst synchronization and chaotic phenomena. Moreover, we found that a novel type of noise-induced order and chaos occur in the system when additive noise are given as a perturbation on the firing threshold. Finally, we will discuss a considerable mechanism of such noise-induced phenomena and the relationship to discontinuity-induced bifurcation in view of the piecewise smooth dynamical system theory.