Fig. 1.

Schematic drawing for all three measures. (A) Illustration of the variables that define the ISI-distance. The instantaneous interspike intervals $x_{\mathrm{ISI}}^{(n)}(t)$ are used as estimates of the local firing rate. (B) Additional variables employed in the definition of the SPIKE-distance. (C) Coincidence criterion for SPIKE-synchronization. The coincidence window of each spike is derived from its two surrounding interspike intervals. Here we illustrate two different examples. The two spikes on the left side are considered coincident since both lie in each other's coincidence windows. On the right there is no coincidence since the spike from the second spike train is outside of the coincidence window from the spike of the first spike train.