Detection of hierarchical modular structure.

(a) Mean fluorescence of pixels, averaged over the full recording session. (b) Co-classification matrix generated using all statistically significant hierarchical levels. The dendrogram to the right depicts module splits. (c) The number of hierarchical levels aggregating data from all mice and all recording sessions. Panels (d), (e), and (f) depict module assignments at different levels of the hierarchy. The network diagrams shown in these panels are identical to one another and represent binarized matrices obtained by thresholding the jitter-adjusted correlation matrix of fluorescence traces between pairs of cells. Panels (g), (h), (i), and (j) depict distributions of z-scored mean intra-module Euclidean distance for each module and for each mouse. Panels (b), (d), (e), and (f) depict representative results from mouse 1. Here, the acronyms “IQR” and “Med.” represent interquartile range and median, respectively. Note also that nodes in panels b and d-f are ordered according to their hierarchical community assignments.