Figure 9.

Action potential dejittering is impaired in AP-3b2 KO mice. A) Example of a natural stimulation train and the corresponding probability of evoked postsynaptic action potentials (B). Responses to small number of stimuli were different in WTs and KOs (5 out of 36). Examples of evoked postsynaptic spikes recorded in WTs (C) and KOs (D), seven responses are shown. Note that the difference in action potential jitter between single stimulation (1 stimulus within 50 ms, left) and burst stimulation (3 stimuli within 50 ms, right) is not present in KOs. E) Plot showing normalized action potential jitter as a function of the number of stimuli within 50 ms in WTs (black, n=18) and KOs (red, n=19). In contrast to WTs, action potential jitter does not change with the frequency of the presynaptic stimulus in KOs and is significantly larger after short burst stimulation. Dashed lines indicate example of corresponding stimulus number in B, stimuli were grouped into categories 1 and 3, respectively. F) Example of postsynaptic APs evoked by 10 stimuli at 20 Hz in KO mice. APs evoked by the third and tenth stimuli are expanded, ten responses are shown. Note similar AP jitter at the beginning and end of the train. G) Average plot showing that AP jitter calculated within 6 ms after stimulation is significantly larger in KOs (n=13) compared to WTs (n=7), and does not decrease significantly during train stimulation. *p < 0.05, **p < 0.01, ^###p < 0.001; Student’s t-test. Error bars show standard error of the mean (SEM).