Extended Data Fig. 2: Dissimilarity of evoked and ongoing assemblies is robust to clustering methods and parameters.
From: Awake perception is associated with dedicated neuronal assemblies in the cerebral cortex
a, Dendrogram plot of the hierarchical binary cluster trees for spontaneous assemblies before and after stimulation in a sample recording session. The horizontal lines indicate the 4 cophenetic distance thresholds tested in the following panels (0.9, 1, 1.2, 1.5). b-e, Correlation matrix for a sample recording in the awake state. The spontaneous assemblies are sorted by hierarchical clustering with thresholds 1, 2, 3, and 4 (in b, c, d, and e respectively) as defined in a. Red squares in the lateral quadrants indicate the maximum similarity pairs. Red squares in the diagonal quadrants indicate clusters and groups. f, Scatter plot and statistics of similarity vs reproducibility (top: evoked/spont. pre.; bottom: evoked/spont.post.) for each threshold value for the example shown in b-e. Reproducibility of spontaneous and evoked assemblies is significantly higher than the similarity of evoked vs spontaneous assemblies independently of the threshold (all p-values equal to 10−9, n = 50 pairs of clusters, Paired Wilcoxon Signed Rank Test). g, Same as in f, but for the anesthetized state under isoflurane in the same sample population (all p-values were above 0.05, n = 50 pairs of clusters, Paired Wilcoxon Signed Rank Test:thresholds: 0.6 (p = 0.66, 0.50), 0.8 (p = 0.43, 0.94), 1 (p = 0.80, 0.94) and 1.2 (p = 0.16, 0.09)). h, Sample matrix where evoked assemblies were clustered in the same way as spontaneous ones (instead of grouping by sound). i, Relation between reproducibility (abscissa) and similarity (ordinate) of sound-evoked and spontaneous pre-stimulation assemblies for all sounds and sessions. Statistics across sessions are given in the right-hand-side histograms (p = 0.03, n = 6 mice). j, Same as in i for evoked versus spontaneous assemblies detected post-stimulation (p = 0.03, n = 6 mice). Paired Wilcoxon Signed Rank Test for i and j. (Corr., Correlation; Repro., Reproducibility; Sim., Similarity; spont, spontaneous; *, *** indicate p < 0.05, p < 0.001 respectively). For all box-and-whiskers plots, the red mark indicates the median, and the bottom and top edges of the box indicate the 25th and 75th percentiles, respectively. The whiskers extend to the most extreme data points not considered outliers, and the outliers are plotted individually using crosses. All tests are two-sided.
