Traditionally, insights into brain function have been largely derived from studying the deficits caused by specific brain lesions. The view emerging from this approach posits a simplified structure-function relationship, in which anatomically distinct brain regions perform specialized, relatively independent computations (e.g. visual cortex is responsible for early visual processing). More recently, this approach has been extended by studies using brain imaging modalities such as electroencephalography (EEG), positron emission tomography (PET), and functional MRI (fMRI) to study brain function both in the resting state (Fox & Raichle, 2007) and during performance of various behavioral tasks. It has become increasingly apparent that complex brain functions, such as coordinated movement, memory and language, depend critically on interactions between brain areas, leading to the concept of functional connectivity networks— distributed brain regions interacting (often transiently) to perform a particular neural function. Studies have suggested that abnormalities in the interactions of network components play a critical role in common neuropsychiatric disorders ranging from depression to epilepsy (Mayberg et al., 2005; Lytton, 2008), and damage to specific functional connectivity networks can lead to distinct neurological syndromes
