Fig. 4: Unbiased identification of the acute decoherence period evoked by ketamine.

a Temporally-binned firing rates plotted onto the first two dimensions of UMAP space. Each point represents a time-bin of population firing rates of recorded neurons. Color-coded by the animals position (top) and by the experimental epoch (bottom). Non-linear dimensionality reduction better clusters out activity by epoch and it is possible to visualize the animal’s position on the looped-linear during the baseline and control sessions. b Raster plots from example cells with spikes identified in the acute-decoherence periods identified by UMAP and HDBSCAN, highlighted in red. c Two example sessions with firing rates dimensionally reduced with UMAP and clustered with HDBSCAN. Colors label clusters identified by UMAP and HDBSCAN. Circled cluster is the acute decoherence period that follows the ketamine injection. d UMAP/HDBSCAN identified trial clusters for each session, decoherence period highlighted in red. e A histogram of the length of identified acute decoherence periods (n = 28 sessions, 10 min bins). f Violin plot comparing firing rate in the decoherence period and the equivalently lengthened control period, averaged over sessions. Firing rates are higher during the decoherence period (two-sided Wilcoxon matched pairs signed rank test, Z = 22.78, p < 10⁻²⁰, n = 2926 cells). The central mark of the boxplot indicates the median, the bottom and top edges of the box indicate the 25th and 75th percentiles, respectively, and the whiskers extend to the most extreme data points not considered outliers. g Histogram of the number of cells that decreased (left) or increased (right) their firing rate during the identified decoherence period (n = 2895 cells, 2007 cells increased, 888 cells decreased). h Violin plot comparing spatial information content in the decoherence period and an equivalent length control period. Spatial information is lower during the decoherence period (two-sided Wilcoxon matched pairs signed rank test, Z = 16.5, p < 10⁻²⁰, n = 2926 cells). Significant comparisons highlighted ****p < 0.0001. All violins have the same area, but the width represents the kernel probability density of the data at different values. Source data are provided as a Source data file.