Bursting dynamics of a model neuron induced by intrinsic channel noise

Irregular switching of ion channels is an inherent source of noise in real neurons. Taking into account the stochastic nature of calcium and fast potassium channel currents in the Plant model of a bursting neuron, we found noise-induced coherent bursting even in the case when the deterministic neuron is silent. The bursts keep their regularity in a wide range of membrane sizes. The measure of this coherence, the coefficierit of variation of interspike intervals, passes through a minimum at the membrane area near 150 mum(2). The degree of coherence obtained from power spectra of spike trains increases monotonously with decrease of membrane size.