Extended Data Fig. 9: Time cells for the other bat.

(a) Scatter plot of the time-field duration (field width at half-height) versus the preferred time, for all the significant time-fields for the other bat, pooled across all three locations (n = 73 significant fields: blue dots; the number of dots here [73] is larger than the number of significant time-cells for the other bat [n = 56], because if a cell was significantly time-tuned on 2 or 3 landing-balls, it contributed 2 or 3 dots to this scatter). This scatter shows a significant positive correlation: Pearson r = 0.27, P = 0.021; Spearman ρ = 0.25, P = 0.035 (two-sided tests). Thus, the resolution of time-fields deteriorated with the passage of time – as for self time-cells (Extended Data Fig. 2d), and as reported for time-cells in rats^7,8,10,17. (b) Firing sequences in simultaneously-recorded time-cells for the other bat are similar to the population time-cell sequences pooled across all days. Distributions of time-differences (∆T) between the preferred-times for all the pairs of significant time-cells for the other, which were recorded simultaneously on the same day (gray bars; n = 28 cell-pairs), and all the cell-pairs recorded on different days (black line; n = 1672 cell-pairs), pooled over the 3 locations in the room. The gray and black distributions were statistically indistinguishable (two-sided Kolmogorov-Smirnov test: P = 0.56). This demonstrates that the pooled sequences for time-cells for the other bat (main Fig. 5c: diagonal panels) are reliably representing the within-day sequences – indicating that time-cells for the other bat form internally-generated firing sequences. (c) Additional 12 examples of time-cells for the other. For each example cell, the top panel shows the color-coded raster plot: x-axis, elapsed time from the moment the bat has landed (time 0); y-axis, repeated landings (trials); plotted as in main Fig. 1e. The bottom panel shows the temporal tuning-curve (black trace), which is the averaged firing-rate of each cell (average of the color-coded raster above); the preferred-time is indicated above the peak-firing of each cell (marked also by a vertical red line); green shading represents statistically-significant time bins; red curve shows the width-at-half-height of the time-field. (d) Venn diagrams showing the distributions and overlap between social place-cells and social time-cells, separately for each of the 4 individual recorded bats. (e) Scatter plot of the time of peak firing of the time-cells for the other bat versus the time of reward (dots show individual trials, pooled across all the example cells shown in main Fig. 5; Pearson r = 0.28; P = 2 × 10^–4; two-sided test; n = 174 trials). Note there was large variability in the time-of-reward (large spread along the y-axis: standard deviation = 1.0 s; mean = 3.18 s), which was substantially larger than the variability in the neurons’ time of firing across the trials (small spread along the x-axis: standard deviation = 0.45 s; mean = 1.38 s).