Left: Bootstrapped cumulative distribution of grid-place cell coherence scores during replay (dark purple) for directionally modulated grid cells (KL divergence > 0.15). Shaded areas shows 1SD of the bootstrap. The x-axis show the grid-place cell coherence scores and the y-axis the proportion of events. Inset: difference between the data and shuffle distributions. Right: same as top except for non-directional grid cells (KL divergence <= 0.15). Both directional and non-directional grid cells showed significantly higher grid-place cell coherence than their shuffle distributions (directional cells: p<0.0001, non-directional cells: p<0.0001, AUC test).