Statistical analysis of interspike intervals (ISI).

<p>(A) The average ISI decreases with the concentration ( = 5) and with ( = 1 ). The other parameter is kept at = 5 and = 1 , respectively. (B) Skewness and (C) coefficient of variation (CV = standard deviation/mean) increase with the channel closing rate , which controls the time scale separation between puffs (single cluster opening) and spikes (all clusters open). The solid lines are calculated for a realistic puff rate . The dotted lines indicate that the time-scale separation becomes weaker with growing puff rate (see text). The parameter values used for the stochastic model (Fig. 3) are indicated by the arrows.