Spike synchrony of the dPAG stimulation-responsive BLA neurons under predatory threats.
(A) Among the 185 CCs of the simultaneously recorded BLA neurons, 14.1% of the pairs showed significant (z > 3) peaks during the robot session. (B, C) The mean CC AUCs (B) and CC peak values (C) were higher during the robot session compared to the other sessions (Zs > 29.36, P < 0.0001, Friedman test; Ps < 0.01 for pre-stimulation vs. robot, stimulation vs. robot, and post-stimulation vs. robot sessions comparisons, Dunn’s test). **, ***, and **** denote P < 0.01, P < 0.001, and P < 0.0001 compared to the robot session, respectively. (D) Among the BLA cell pairs that significantly synchronized during the robot session, 61.5% of the pairs (stim pairs) included dPAG stimulation-responsive BLA cells while 38.5 % of the pairs (non-stim pairs) did not. (E) Spike synchrony of the stim pairs. A representative CC of a stim pair (top) showed increased correlated firing during the robot session. The mean CC AUC (bottom, left) and CC peak (bottom right) of stim pairs during the robot session were higher than those during the other sessions (Zs > 17.42, P < 0.001, Friedman test; Ps < 0.037 for pre-stimulation vs. robot, stimulation vs. robot, and post-stimulation vs. robot sessions comparisons, Dunn’s test). *, **, and *** denote P < 0.05, P < 0.01, and P < 0.001 compared to the robot session, respectively. (F) Spike synchrony of the non-stim pairs. The representative CCs show significant correlated firing during the robot session in the non-stim pairs (top). The CC AUC (bottom left) did not differ between the robot and pellet-only sessions (pre- and post-stim sessions) while peak area during the robot session was higher than that during the stim session (Z = 13.84, P < 0.01, Friedman test; P = 0.0017 for the stimulation vs. robot sessions comparison, Dunn’s test). The CC peak (bottom right) during the robot session was higher than those during the stimulation and post-stimulation sessions (Z = 15.92, P < 0.01, Friedman test; Ps < 0.0335 for stimulation vs. robot and post-stimulation vs. robot sessions comparisons, Dunn’s test), but not the pre-stimulation session. *, **, and *** denote P < 0.05, P < 0.01, and P < 0.001 compared to the robot session, respectively. (G) Stim pairs showed higher correlated firings than the non-stim pairs during the 20-40 ms time period after the paired cell fired (U = 32, P = 0.011; Mann-Whitney U test) while they showed lower correlated firings than the non-stim pairs during the 60-100 ms time window of the CCs (60-100 ms; Us < 37, Ps < 0.023; Mann-Whitney U test). * denotes P < 0.05 compared to the non-stim pairs. (H) The CC peaks of the stim pairs during the robot session tended to be higher than those of the non-stim pairs (U = 43.0, P = 0.051; Mann-Whitney U test).