Supplementary Figure 4: Representative raw cross-correlations demonstrating potential increased variability with smaller time bin widths.

Related to Figure 2. Cross-correlations for each neural pair (individual columns) are represented in triplicate using three different bin widths: 25 ms (top row), 10 ms (middle row), and 5 ms (bottom row). Significant correlations are displayed as solid lines, and non-significant correlations are displayed as dotted lines. Significant peaks are indicated by colored dots. While these examples illustrate the y-axes as PL spike probability, the significance of each correlation was assessed using our compound criteria based on z-score thresholds after correcting with the trial-shifting and spike-shuffling predictors (as in Supplementary Fig. S3a). (a) Correlograms between representative BLA and PL cells with moderate firing frequencies that showed consistent peaks and lead/lag timings across all three bin widths. (b) Correlograms between representative BLA and PL cells with relatively low firing frequencies that showed peaks and lead/lag timings that were somewhat inconsistent across the distinct bin widths. (c-d) Example correlograms between representative BLA and PL cells with either low or moderate firing frequencies that exhibited spurious significant peaks when using the narrowest 5-ms bin widths, raising concerns for false positives due to the increased variability obtained with the small bins. (e-f) Example correlograms between representative BLA and PL cells both with relatively low firing frequencies that also showed spurious significant peaks with the smaller bin widths. These examples also raised concerns for false positives when using small bin widths due to sparse firing. (g) Example correlograms that represent the potential for false negatives with the 5-ms bins, which may be due to splitting of the peaks among adjacent bins, or due to the more stringent z-score criteria, which required additional corrections for multiple comparison in the case of the 5-ms bins compared to the wider bin widths. In summary, our dataset provided more reliable cross-correlation results when using the relatively wider bin widths (25 ms).