Early analysis of fMRI data looked for correlational evidence of brain regions being related to specific functions (known as functional segregation). However, it became obvious that the brain operates as a global complex system with many interactions (functional integration). While a large body of work in the literature focuses on structural connectivity of the brain, that is, how white matter interconnects brain regions, some authors have attempted to model and characterize the brain as a network using functional connectivity (i.e., temporal correlation between remote brain regions). This network-centric perspective has led to fundamental insights in terms of the organization of the healthy and diseased brain, how its resilient