Figure 6.

Spike timing deviation in absence and presence of SKF-81297. Spiking elicited and recorded using same methods as in Figure 5. Spike timing was compared moment-by-moment in three 10 s traces recorded ≤4 min before application of SKF-81297 (A), and in three 10 s traces recorded 12–16 min after application of SKF-81297 (B). For each condition, if spikes occurred at similar times in all three traces (i.e., if spikes were “temporally coaligned”), the difference between the time of each spike and the average of the times of the coaligned spikes was measured, and tallied accordingly in A or B. Time was measured from beginning of each current injection to moment of maximum change in slope (dV/dt) along rising phase of each spike. Histograms are binned at 0.2 ms, and include 165 (55 × 3) and 81 (27 × 3) spikes for A and B, respectively. Insets superimpose examples of spikes considered to be coaligned in traces recorded before (A) and after (B) SKF. All six traces (labeled a–c in A and in B) begin at identical times after start of each 10 s current injection. C, Percentage distribution of spike timing deviation. Spike number in A and B was normalized by respective total spike number and the two histograms were overlaid, with gray signifying overlap of the before (clear) and after SKF (filled) distributions.