Spike-timing property of a pair of simultaneously recorded Purkinje cells during the saccade task. A: a Purkinje cell was isolated by contact 5 and another one by contact 6. Data recorded by contact 6 (top) were triggered by simple spike events on contact 6 (left) and by simple spike events on contact 5 (middle); data on right were recorded by contact 6 and triggered if there was a simple spike event in both contacts 6 and 5 within 1 ms of each other. Bottom shows waveform for contact 5. On average, spikes in one contact did not produce a significant voltage change in another contact, and the shapes of synchronous (within 1 ms) and nonsynchronous spikes were nearly identical. B: to measure coordination among the Purkinje cells, we triggered the waveform on contact 6 by the spikes on contact 5. The pattern of coordination is quantified via the conditional probability Pr[S6(t)|S5(0)]. C, left: the probability of simple spikes at time t, given that a complex spike occurred at time 0 in another channel, quantified by Pr[S5(t)|C6(0)] and Pr[S6(t)|C5(0)]. There is no suppression of simple spikes following a complex spike. Right: the probability of co-occurrence of the complex spikes, Pr[C5(t)|C6(0)]. The 2 cells did not produce complex spikes that were strongly coordinated. Prob., probability.