The correlated nature of large-scale neural activity unveiled by the resting brain.

Most of functional neuroscience studies investigate the brain's response to a task or stimulus. However, the brain is very active even in the absence of an external or internal input. Recent neuroimaging, electrophysiological and optical imaging studies revealed that the neural activity at rest is structured in functionally specific, temporally correlated, spatially distributed patterns that explain a large part of the variability of event-related responses. These results importantly extend the focus of cognitive neuroscience from the stimulus-evoked responses to the spatial and temporal correlations between different neural populations. I argue that integrating the correlated nature of the neural activity to standard measures of evoked responses might significantly advance our understanding on the neural mechanisms underlying cognitive functions. This perspective may be tackled by identifying spontaneous spatiotemporal patterns of neural activity at rest and tracking their evolution and dynamical interactions during cognitive processing.