Supplementary Figure 3: Criteria used for the detection of significant correlations between the BLA and PL cells, and side-by-side results with multiple time bin sizes.

Related to Figure 2. (a) Cross-correlograms were calculated using 25-ms time bins, they were then corrected using two different predictor methods (trial shifting and spike shuffling) to eliminate confounds produced by CS-elicited changes in firing frequency, and they were then z-score transformed to detect significant peaks or troughs. (a1) Correction by shifting trials (repeated 19 times per trial type). (a2) Correction by shuffling spike trains (repeated 100 times per trial type). (a3) Repetition of the analysis using 5-ms time bins to detect and exclude “zero-lag correlations” (i.e., peaks or troughs that are centered at zero, ±2.5 ms), which typically result from common input-induced comodulation. The resulting correlograms from the shift and shuffle predictors (second column) were subtracted from the raw correlograms (first column), and the difference was z-score transformed (third column; zoomed in on the fourth column) to detect significant peaks or troughs within the time window of interest (±100 ms). Peaks or troughs were required to reach a z-value threshold (indicated by dashed horizontal lines) that was calculated based on a P-level of <0.01 (corrected for two-tail comparisons and Bonferroni-corrected for multiple comparisons). Significant peaks in these representative correlograms are indicated with colored dots for each trial type. To classify neural pairs as significantly correlated, peaks or troughs were required to exceed the significance threshold after correcting with both predictor correctors (trial-shifting and spike shuffling), and do not show "zero-lag" latencies in the 5-ms binned correlograms. In addition, neural pairs were classified as either “BLA led” if peaks or troughs occurred within the range of +2.5 to +100 ms, or as “PL led” if peaks or troughs occurred within the range of -100 to -2.5 ms, relative to the BLA reference spikes. (b-c) Side-by-side cross-correlation results using either 25-ms or 10-ms bin widths. Numbers within the heatmaps represent the proportion of significantly correlated BLA/PL neural pairs during the CS-Suc and CS-Shock trials. Inset heatmaps show zoomed in views of the time window of interest (±100 ms). (d-e) Lead and lag results using either 25 ms or 10 ms bins. With both bin widths, excitatory correlations were likelier to be led by the BLA during the CS-Shock trials, whereas inhibitory correlations were likelier to be led by the BLA during the CS-Suc trials. Chi-square tests for the 25-ms binned excitatory CCs: X² = 29.8 and ***P < 0.001 (BLA vs PL during the CS-Shock), X² = 16.0 and ***P < 0.001 (CS-Suc vs CS-Shock ratios). Chi-square tests for the 25-ms binned inhibitory CCs: X² = 5.99 and *P = 0.014 (BLA vs PL during the CS-Suc), X² = 5.70 and *P = 0.017 (CS-Suc vs CS-Shock ratios). Chi-square tests for the 10-ms binned excitatory CCs: X² = 21.0 and ***P < 0.001 (BLA vs PL during the CS-Shock), X² = 14.4 and ***P < 0.001 (CS-Suc vs CS-Shock ratios). Chi-square tests for the 10-ms binned inhibitory CCs: X² = 0.67 and P = 0.41 (BLA vs PL during the CS-Suc), X² = 1.18 and P = 0.28 (CS-Suc vs CS-Shock ratios). (f-g) Mean latency of peaks and troughs. Boxes represent the median and the 25^th to 75^th percentiles, whiskers represent the 10^th and 90^th percentiles, and the plus signs (+) within the boxes represent the mean latencies per event. The mean latencies for the excitatory correlations with the 25-ms bins were as follow: CS-Suc, 5.9±2.5 ms; CS-Shock, 13.0±2.4 ms (unpaired T-test: t₆₂₃ = 2.05, *P = 0.041). The mean latencies for the inhibitory correlations with the 25-ms bins were as follow: CS-Suc, 17.1±7.6 ms; CS-Shock, -1.4±5.2 ms (t₉₅ = 1.95, ^~P = 0.055). The mean latencies for the excitatory correlations with the 10-ms bins were as follow: CS-Suc, 2.0±2.7 ms; CS-Shock, 8.1±2.5 ms (t₆₂₃ = 2.05, ^~P = 0.064). The mean latencies for the inhibitory correlations with the 10-ms bins were as follow: CS-Suc, 9.5±15.0 ms; CS-Shock, 8.2±8.9 ms (t₃₄ = 0.08, P = 0.94).