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. Contrast with Task Positive Network (TPN).

A network of different parts of the brain that activate when people are not focused on activities requiring their direct attention or active engagement. An example of such an activity would be mind-wandering. The activation of the brain in this network is of note to researchers, who see it as neural activity that activates when we find ourselves 'doing nothing.' In fact, the Default Mode Network is involved in consolidating memories, self-reflection, and engaging in 'mental time travel' - imagining the self in the past, and planning for the future.

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