Limited impact of fear conditioning on spontaneous neurotransmission in the basal nucleus. A, Schedule for obtaining electrophysiological or behavioral measurements for all trained mice. Training entailed six pairings of pure-tone CS (2 kHz, 20 s, 80 dB) with scrambled footshock US (0.7 mA, 2 s), while naive mice were selected from cage-experienced littermates. B, C, Freezing during fear conditioning (B) and retrieval test (C). *p < 0.0001, paired t test versus baseline (n = 10). D, Representative sEPSC traces at −60 mV. Calibration: 10 pA × 400 ms. E, F, Cumulative distribution and group means for frequency (E) and amplitude (F) of sEPSCs, *p < 0.05, two-tailed t test [n = 12 (5) naive, 14 (4) trained]. G, Representative sIPSC traces at 0 mV. Calibration: 30 pA × 300 ms. H, I, Cumulative distribution and group means for frequency (H) and amplitude (I) of sIPSCs [n = 9 (3) naive, 11 (3) trained].