Default Mode Network (DMN)

Discrete, bilateral, and symmetrical cortical areas, in the medial and lateral parietal, medial prefrontal, and medial and lateral temporal cortices of the human, nonhuman primate, cat, and rodent brains. In the human brain, the DMN is a constellation of areas in the cerebral cortex that consistently reduces its activity while performing various novel, non-self-referential, goal-directed tasks. The DMN operates in the background and is active when the brain is not focused on the outside world (e.g., mind-wandering, daydreaming). It becomes deactivated during goal-directed tasks. See also Task Positive Network (TPN).

Reference:

Raichle, M. E. (2015). The brain's default mode network. Annual Review of Neuroscience, 38(1), 433-447. https://doi.org/10.1146/annurev-neuro-071013-014030