Fig. 2: Replay dynamics across spatial behaviours during aerial foraging.
From: Replay and representation dynamics in the hippocampus of freely flying bats
a, Example flight trajectories (top view) from one bat during a representative session. Flights are clustered into similar paths (colours); arrow denotes take-off. Scale bar, 1 m. b, Example posterior probabilities (squares) for candidate replays decoded using place fields from different trajectories (traces). Note the decoding specificity of replays. Scale bar, 1 m. c, Normalized replay rate (grey) and flight times (orange lines) during a session. Scale bar, 5 min. d, Replay rate around flight times (orange, within 30 s of a flight) versus periods of rest (grey, more than 30 s away from a flight). Bars denote the average replay rate; vertical lines denote s.e.m. ***P = 9.7 × 10−8, two-sided Wilcoxon signed-rank test (n = 71 trajectories from 19 sessions across 5 bats). e, Left, example of a local replay. Black dot, position of bat at time of replay; arrow, take-off; black trace, average flight trajectory being replayed. Middle, same, but for a remote replay. Scale bar, 1 m. Right, bar plot for the median proportion of local and remote replays (n = 19 sessions, 5 bats). f, Pie charts showing the percentage of spatial and temporally local replays with varying thresholds (the replays shown in the chart meet both spatial and temporal proximity criteria simultaneously). Δs, distance between location of bat at time of replay and start location of replay; Δt, time interval between replay and take-off (forward) or landing (reverse) of nearest replayed trajectory (n = 2,050 forward replays, 837 reverse replays from 23 sessions and 6 bats). g, Left, cumulative distribution of flight trajectory lengths (73 trajectories, 23 sessions from 6 bats). Shaded coloured rectangles are the groups of short and long flights used in i. Right, example average trajectories (top view) for different lengths. h, Example raster plots for forward replays of trajectories with different lengths, sorted from bottom left to top right. Note the near constant duration of replays across lengths. Scale bar, 500 ms. i, Top, average flight duration (left) and length (right) for the group of short (n = 37) versus long (n = 28) flight clusters (see g). Two-sided P = 7 × 10−12 and P = 7 × 10−12, Wilcoxon rank-sum test. Bottom, average replay duration (left) and speed (right) for the same groups. Two-sided P = 0.796 and 9.56 × 10−5, Wilcoxon rank-sum test; NS, not significant (n = 37 versus n = 28 flight clusters). Thick line represents median, coloured area (violin) represents the data distribution across flight trajectories. Note that replay speed, but not duration, scales with flight length.
