Methods for identifying cortical hubs and networks. A, The basis of the present methods is the intrinsic BOLD signal fluctuations that correlate between brain regions reflecting monosynaptic and polysynaptic connections. B, The functional connectivity matrix was computed to represent the strength of correlation between every pair of voxels across the brain; the pattern of these connections is the functional connectivity network (example is of a binary matrix and network of 1000 nodes). C, To determine cortical hubs, the degree of connectivity of each voxel was computed and projected onto the cortical surface of the brain. Candidate hubs are those regions with disproportionately high connectivity and are plotted in yellow and red. D, As a secondary analysis, the networks associated with identified hubs were determined by seeding individual regions located at the peak of the hub and determining the subnetworks that showed correlation.