A. Examples of averaged IPSCs induced by brief (1 ms) laser pulses. The left panel (a) is subtracted from the middle panel (ab) to give the right panel (c). B. Examples of IPSCs in one cell in response to paired laser pulses at varying interpulse intervals. C. Pooled data of 9 cells, showing the ratio of paired-pulse inhibition amplitudes as a function of paired laser-pulse intervals. Note that the response to the second pulse disappears, but then recovers to ∼30% and ∼80% of the amplitude of the first pulse for interpulse intervals of ∼10, ∼25 and ∼70 ms, respectively. D. Examples of averaged IPSPs induced by photo stimulation similar to A. E. Pooled data of 7 cells, showing that the inhibition is largely recovered for an interpulse interval of ∼100 ms. Note that some cells were recorded under both voltage- and current-clamp configurations, and are therefore included in both groups.