Other studies have focused on EEG measures of functional connectivity between distant cortical regions. A theory of spatiotemporal organization of cerebral function (Livanov, 1977) posits that dynamical functional networks supporting goal-directed behavior are formed by the synchronization of neural oscillations in distributed but functionally connected brain regions. One of the most frequently used metrics of large-scale synchronization of cortical oscillations is EEG coherence, a measure of phase consistency between two oscillatory processes at a given frequency which is analogous to a linear correlation.
