a, Fear extinction training for ex vivo mIPSC recordings in the BLA (conditioned (cond), n = 3; 1 d CS, n = 2; 1 d ABS + CS, n = 3; 7 d CS, n = 3; 7 d ABS + CS, n = 3 mice). Statistical analysis was not performed because of the small sample size. b, Optical fibre placements for MD–BLA silencing experiments. c, Viral injections used to visualize the MD–BLA projection. The results (d, e) were replicated with seven mice including five mice obtained after whole-cell recording (h). d, Coronal section under excitation with low laser power optimized for visualizing fluorescence in MD area. e, Coronal section under excitation with high laser power optimized for visualizing fluorescence in the BLA complex. CeA, central amygdala. f, Viral injection (top) and whole-cell recording (bottom) for the feedforward inhibition test. g, Sample traces evoked by photostimulation of MD fibres. h, Averaged latencies of EPSCs (B6/J, n = 7; Grik4-cre, n = 8 cells) and IPSCs (B6/J, n = 11; Grik4-cre, n = 6 cells) from the laser onset to 10% rise time. i, j, Light-evoked outward currents recorded at +10 mV were blocked by bicuculline (i) or CNQX and d-AP5 (j), indicating that recorded currents represent feedforward inhibition. k, Fear extinction training for ex vivo recording of MD–BLA synaptic transmission (CS, n = 3; ABS + CS, n = 3 mice). Mixed-design ANOVA: F1,4 = 7.305, P = 0.0539 for group effect. Data shown as mean ± s.e.m. See Supplementary Table 1 for statistical details.