(a) Left: Average difference in distance offset between same (S) and randomly (R) chosen cell pairs. Data are plotted as in Fig. 5b,c. Red line indicates median difference in offset of the displaced center peak, box edges indicate 25th and 75th percentiles, whiskers extend to the last data point that lies within 1.5 times the interquartile range, and data points larger than 1.5 times the interquartile range are considered outliers (black dots). Rat number and trial date are indicated at the top. Number of cells and cell pairs are indicated at the bottom right (***P < 0.001, two-sided Wilcoxon rank sum test). Center: Average angular difference of orientation offset between same and random cell pairs (***P < 0.001, Watson U2 test). Right: Pairs of grid cells share the same orientation and spacing. Average correlation of autocorrelograms for all cell pairs. Stippled red line indicates 90th percentile of all pairwise correlations from all cells and rats (n = 128 cells / 8128 pairs). (b) – (f) As in a but for different trials or animals (**P < 0.05, Watson U2 test).