EPSC latency in three neuron groups. A, representative traces of EPSC1 evoked by TS stimulation (arrowheads). Left, averaged waveform (black; n = 11) and overlay of each waveform (gray) of the rising phase of EPSC1 responses in type I and type II DMX neurons and dm-cNTS (NTS) neurons; eleven consecutive responses. Note that the time between the stimulation and the beginning of downward deflections (latency) was constant across trials in these neurons. The latency values were 3.7, 4.0 and 4.3 ms for these type I DMX, type II DMX and dm-cNTS neurons, respectively. Right, averaged traces showing the responses to paired-pulse TS stimulation at an ISI of 100 ms. Note the different time scales between the left and right panels. The PPR values for these neurons were 0.86, 0.40 and 0.18 for type I DMX, type II DMX and dm-cNTS neurons, respectively.B, histogram showing the distribution of EPSC latency in type I (n = 6), type II DMX (n = 10) and dm-cNTS neurons (n = 16). The latency was measured in the EPSC recordings in which the onset of EPSC waveforms could be unequivocally defined, free of artifacts from the preceding stimulation.C, summary and comparison of the mean latency between type I and type II DMX and dm-cNTS neurons. The latency for EPSC in dm-cNTS neurons was slightly but significantly longer than that in DMX neurons. **, p < 0.01; one-way ANOVA.D, histogram showing the distribution of the SD of EPSC latency over 11 trials. E, summary and comparison of the standard deviation of latency among type I DMX, type II DMX and dm-cNTS neurons. There was no significant difference in the SD of latency for EPSC in these three classes of DVC neurons (one-way ANOVA).