Fig. 1: Wireless recordings with Neuropixels probes during aerial foraging reveal hippocampal replay in bats.

a, Top, schematic of the aerial foraging experiment. Bottom, dorsal hippocampus (coronal section) in one recorded bat, stained for 4′,6-diamidino-2-phenylindole (DAPI, blue) and CM-DiI (red) (Methods). White dashed lines marked with arrowheads denote tracks of three implanted Neuropixels 1.0 probes. Scale bar, 1 mm. b, Raster plot of simultaneously recorded hippocampal neurons during a representative session. Neurons are sorted by average firing frequency. Bottom trace, average hippocampal LFP across all channels of one probe during the same session. Scale bars, 800 μV (vertical) and 1 min (horizontal). c, Top, similar flights from a representative session. Arrow indicates take-off. Bottom, raster plot of simultaneously recorded place cells, sorted by the location of their firing field (Methods). Each row shows the firing during 22 consecutive repetitions of the same trajectory. Neural activity is plotted along a normalized flight trajectory, with all flights temporally aligned and rescaled (yellow shaded area) such that take-off and landing coincide in the visualization. Scale bar, 2 m. d, Neural activation of place cells during a representative epoch. Top, raster plots showing sorted neural activity during time-compressed candidate replays (red rectangles) and during a flight (blue shaded area on the right). Note the different temporal scales. Neurons are sorted by the location of their firing fields. Middle, raster plot from the same neurons, showing their activity during the entire epoch. Bottom, spike density from the same neurons. e, Distribution of rank-correlation values for all candidate replay events (n = 16,468, from 23 sessions and 6 bats; Methods). Grey distribution indicates non-significant events and red distribution significant events (P value from rank-correlation analysis; Methods). f, Decoded probability of linearized position (take-off location is at the bottom; Methods) for example replay events. Numbers indicate the temporal and spatial scale of each replay. g, Left, example LFP across a subset of contacts (for visualization) during a representative SWR event. Scale bar, 100 ms. Middle, example raster plots (top) and LFP epochs in the pyramidal cell layer (bottom) during representative replays. Note the coincidence between replay and one or more SWRs. Scale bar, 350 ms. Right, average cross-correlogram between replay and SWR times (n = 23 sessions from 6 bats). Illustration in a adapted from ref. ¹⁴, Springer Nature Limited, under a Creative Commons licence CC BY 4.0.

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