  Modular structure is ubiquitous among real-world networks from related
proteins to social groups. Here we analyze the modular organization of brain
networks at a large-scale (voxel level) extracted from functional magnetic
resonance imaging (fMRI) signals. By using a random walk-based method, we
unveil the modularity of brain-webs, and show that modules with a spatial
distribution that matches anatomical structures with functional significance.
The functional role of each node in the network is studied by analyzing its
patterns of inter- and intra-modular connections. Results suggest that the
modular architecture constitutes the structural basis for the coexistence of
functional integration of distant and specialized brain areas during normal
brain activities at rest.
