Effects of 8-OH-DPAT and CP93129 on spike timing. A. PSTHs for one neuron in response to 8-OH-DPAT, CP93129, or drug co-application (‘both’). Values for latency are the median latencies of the first spikes in each condition, in ms. The bin size is 500 μs and the total duration of the PSTH is 30 ms. PSTHs are accompanied by raster plots showing the spike timing for each stimulus repetition. Black dots represent first spikes, and gray dots represent subsequent spikes. B. PSTHs and rasters for a second neuron. The bin size is 100 μs and the total duration of the PSTH is 6 ms. For both neurons, the order of drug treatments represents the sequence of drug application.