Figure 12. Postsynaptic spikes.

At membrane potentials less negative than -69 mV, second, third and fourth EPSPs (but very rarely first EPSPs) in brief trains could trigger postsynaptic spikes in this interneurone. This figure illustrates the short and constant latencies of these postsynaptic spikes, although the spike AHP varied from sweep to sweep. On the left, 3 single sweep responses to pairs of presynaptic spikes are superimposed. On the right a single sweep response to a train of 4 presynaptic spikes is shown. Sweeps including postsynaptic spikes were excluded from the averaged EPSPs illustrated in other figures.