Fig. 6

Largely non-overlapping distribution of highly active and highly connected regions in the resting state human brain. A Overview of the classification of individual ROIs (brain regions, n=105) based on their level of activity and functional connectivity (degree). Variations of the brain region activity across time was used as a measure of activity and the Pearson correlation of brain regions’ activity was used a measure of functional connectivity (degree). The k-means clustering algorithm was employed to cluster the brain regions into three levels based on each measure. B Percent of total ROIs in each activity level category. C Percent of total ROIs in each functional connectivity level category. D Highly active (red) and highly connected regions (green) across all subjects (n=74). E Connectivity levels (Y-axis) of all brain regions sorted based on their activity (X-axis) in an example subject. Red and blue boxes denote regions of high activity and high functional connectivity, respectively. The dotted circle denotes where highly active and highly connected brain regions are expected to locate. F The population distribution curve of brain regions with different levels of activity and functional connectivity. Note that brain regions that have high activity and high connectivity are non-existent. The number of replicates used is 74