Figure 3

Results of Series I: Changes induced in spontaneous bursting by strong stimulation through several electrodes. A An exceptional example from protocol I.1, where the induction sequence resulted in reduced burst rates and sizes. Note though, that spontaneous drift in the burst rate before the analyzed portion of the recording was of comparable magnitude. B A typical example from protocol I.2, showing no effect. Induction sequences in A and B are marked by gray bars. Top to bottom: number of spikes in individual bursts; number of bursts in successive one-hour time windows (with error bars based on assumed Poisson statistics); total number of spikes in bursts in successive hours. C A summary of all experiments in Series I shows that changes concomitant with induction were no larger than spontaneous changes. D Comparison of spontaneous changes and changes concomitant with induction in hourly burst rates. Unlike in C, all changes were normalized to the hourly burst rate before the induction sequence. Data are mean ± SEM of absolute values of changes; N = 4, 16, 8 for protocols I.1, I.2, I.3 respectively. Paired t-tests revealed no significant effects of the induction sequence.