Figure 4.

Observational fear training (OF) attenuates depression of dendritic inhibitory postsynaptic currents (IPSCs). (a) Experimental scheme. Stimulation of dmPFC layer I, voltage-clamp recording from the layer V principal neuron held at 0 mV and puffing picrotoxin on soma of the recorded neuron are illustrated. Directions of puffing and ASCF flow are shown. (b). Picrotoxin puff on soma eliminated above 80% of spontaneous IPSCs (sIPSCs) and decreased sIPSC amplitude. Left: an example of sIPSC recorded before and after a somatic puff of picrotoxin. Right: summary data for sIPSCs detected within 1 min before (Baseline) and after (Picrotoxin) puff of picrotoxin (1 mM): sIPSC frequency normalized to the baseline value and absolute amplitude. Data were merged from control and OF groups, six cells/three mice each, as picrotoxin effects were same between the groups. (c) Left: examples of IPSCs evoked by 5 Hz train of electrical pulses, averages of five sweeps are shown. Right: IPSC amplitudes and charge transfers normalized to the values of the first IPSC, control: 11 cells/3 mice, OF: 12 cells/3 mice. (d) Same experiment as in c, in the presence of CGP52432 (10 μM), control: 15 cells/3 mice, OF: 15 cells/3 mice. Black and gray colors represent control and OF groups, respectively. Baseline vs Picrotoxin, or OF vs control: *p<0.05, **p<0.01, ***p<0.001, and ****p<0.0001. Error bars represent SEM.