Fig. 4: Distinct modular structures during different types of visual stimuli.

A (top) Topological structure of functional connectivity of a mouse during six types of visual stimuli with neurons colored by area. The color of each connection shows its sign with red denoting positive connection and blue representing negative correlation. The community partition is obtained through modified Modularity for signed networks (see Methods). (bottom) We computed the Z-score of Modularity with Signed-pair-preserving model as the reference to show the degree to which functional network has a modular structure. Networks during gratings and natural stimuli show significant modular structure. Error bars represent standard error of the mean and are displayed with mean, n = 7 mice. B We used three measures to reveal the modular structure regarding visual area from different perspectives. Coverage and purity are module-level measures, where the former marks the degree to which the module covers any visual area, while the latter measures the degree to which all neurons in the module are from the same visual area. We computed the average coverage and purity weighted by module size to show the overall properties of the whole functional network (see Methods). Adjusted Rand Index (ARI), a network-level measure, was also used to quantify the difference between module partition and visual areal organization. The weighted average (WA) coverage is 0.375 and 1 (ranges from 0 to 1), WA purity is 0.333 and 1 (ranges from 0 to 1) and ARI is −0.03 and 1 (ranges from −0.5 to 1) for the corresponding two toy examples visualizing the “low” and “high” cases for the measure. C WA coverage, WA purity and ARI during six visual stimuli. In general, there tend to be fewer and larger modules with higher coverage during grating stimuli, whereas we usually find more and smaller modules with higher purity during natural stimuli. As a result, ARI is lower during resting state and flash while higher during grating and natural stimuli. Error bars represent standard error of the mean and are displayed with mean, n = 7 mice.