Fig. 2: M2 resting ensembles preferentially recruit neurons expressing high spatial information.
a Illustration of hierarchical clustering method used to detect synchronous neuronal ensembles during rest. A 1 min segment of REST2 from the same recording as Fig. 1c–d is shown. Neurons were sorted by similarity in time course vectors. Black vertical bands highlight movement epochs, which were excluded from analysis. The Pearson correlation matrix between the time-series of neuron pairs is illustrated, along with the dendrogram obtained from hierarchical clustering. Neurons part of a synchronous ensemble were grouped by the same colour. Coloured dots over the time-series mark reactivation events detected for individual ensembles. b The mean deconvolved ΔF/F0 as a function of position and laps for all individual neurons in the three synchronous ensembles in a. Neurons were sorted by place field location. Notice that neurons of the same ensemble share neighbouring place fields. c The mean activity of the neurons in b as a function of position. d The fraction of spatially-selective neurons that were part of REST1 and REST2 synchronous ensembles, and the overall fraction of spatial cells in all recording sessions (n = 14 mice; n = 86 sessions; p = 0.034 for REST1-REST2; not significant between other groups; Kruskal-Wallis H test). e Difference between the fraction of spatially-selective neurons within synchronous ensembles and the overall fraction of spatial cells (n = 14 mice; n = 86 sessions). REST2 ensembles contained a significantly higher fraction of spatial cells (p = 7.299 × 10−5; one-tailed Wilcoxon signed rank test for the null hypothesis of median smaller or equal to zero), while REST1 ensembles showed no significant deviation from baseline (p = 0.92). f Cumulative distribution functions of spatial information for REST1 and REST2 neurons that were part of synchronous ensembles (n = 2672 REST1 and n = 3613 REST2 neurons; p = 1.773 × 10−15 two-tailed Kolmogorov-Smirnov test; p = 1.22 × 10−18 two-tailed Mann-Whitney U-test). g Percentage of explained variance (ev) and reverse explained variance (rev) in all imaging sessions (n = 14 mice; n = 86 sessions; p = 1.815 × 10−15; paired-sample one-tailed Wilcoxon signed rank test for the null hypothesis of median smaller or equal to zero). All box plots show the median (line), the first and last quartiles (box), the minimum and maximum values (whiskers) and the outliers (circles). Source data are provided as a Source Data file.
