A novel dynamical mechanism of neural excitability for integer multiple spiking

Integer multiple spiking is special firing behavior which has been already observed in a variety of neurophysiological experiments. In previous studies, many model neurons have been used to investigate the underlying mechanisms for the integer multiple spiking. However, these studies principally involved one case of dynamical mechanisms of neural excitability: the deterministic model neuron resides near a Hopf bifurcation (including supercritical and subcritical). In fact, it is well known that there are two frequently observed dynamical mechanisms of neural excitability, namely, Hopf bifurcation and saddle-node on invariant circle bifurcation. In this study, we consider the latter case at the first time and observe the firing behavior of integer multiple spiking by use of the Morris-Lecar model neuron near a saddle-node on invariant circle bifurcation subjected to a subthreshold periodic stimulus and a Gaussian white noise. Thus, we show that saddle-node on invariant circle bifurcation is a novel dynamical mechanism for integer multiple spiking. At the same time, we uncover a neuron with integer multiple spiking may employ the phenomenon of stochastic resonance to detect external weak signals and transmit neural information. (C) 2003 Elsevier Ltd. All rights reserved.