Analysis of history-dependent interspike interval duration in simulated motoneurons.

Top row: model with h-current, bottom row: model without h-current. Baseline frequency 10 Hz, no noise, inhibitory postsynaptic current (IPSC) amplitude -10 nA. (a, c): Membrane potential trajectory without stimulus (black, undisturbed interval) and with stimulus applied at two exemplary time points (blue, green). Dashed arrows mark IPSC application time with respect to the last discharge (t_stim) and solid arrows mark change of interspike interval with respect to the undisturbed interval (Δ ISI). Insert in (a) shows h-current for the shown interspike intervals between 40 ms and 100 ms. Here, a positive sign indicates current flux into the cell. (b, d): Change of interspike interval duration (Δ ISI) over time of IPSC application with respect to the last discharge (t_stim). Intervals shown in (a) and (c), respectively, are marked with asterisks. Dashed lines separate prolonged interspike intervals (inhibition) from shortened interspike intervals (excitation).