Default mode network; Task-negative network
The default network is a system of brain regions that is active when there are no external cognitive demands. The greatest brain activity is observed in this system during unstructured rest, and the least activity is observed during tasks that require concerted external focus. The existence and core location of the default network are widely accepted; however, its function and subsystems remain under investigation. The default network is distributed bilaterally and is comprised of at least two core midline regions, the posterior cingulate cortex and medial frontal gyrus, plus the inferior parietal lobule and areas in the medial and lateral temporal lobe.
Identification of the default network emerged unexpectedly from functional neuroimaging studies that administered paradigms with a variety of active cognitive challenges. Functional neuroimaging designs frequently sample brain activity during resting...