Variability of bursting patterns in a neuron model in the presence of noise
Divalent ions, which block Ca currents, combined with partial block of outward currents give rise to slow plateau-like oscillations (10}50 s period) with long duration plateaus and long inter-plateau intervals in leech heart interneurons (Opdyke, Calabrese, J. Comp. Physiol. 175 (1994) 781}789.) We present a simpli"ed mathematical model that replicates the main characteristics of these observations and suggests an underlying biophysical mechanism. A model containing transient Na current (I ), leakage and outward currents can generate oscillations with long plateau duration. The plateaus arise from a window mode of I and do not require noninactivating Na current (I ). The long inter-plateau intervals are produced reliably after including I . 2001 Elsevier Science B.V. All rights reserved.