What Is the Default Mode Network?
The default mode network (DMN) is a system of connected brain areas that show increased activity when a person is not focused on the outside world.
The DMN is especially active, research shows, when one engages in introspective activities such as daydreaming, contemplating the past or the future, or thinking about the perspective of someone else. It is also active when a person is awake, but in a resting state, not engaged in any demanding, externally oriented mental task—hence the word “default.”
The DMN spans a number of brain regions, incorporating parts of the prefrontal, parietal, and temporal cortices that show joint activation (or deactivation) in connection with particular mental functions. It is one of a number of such brain networks, which also include the salience network and the executive control network.
Why Does the Default Mode Network Matter?
In addition to its connection to essential states of self-focus, social cognition, and mental time-travel, the activity of the default mode network appears to be related to varied forms of mental illness. Researchers have reported lower connectivity between the components of the DMN in patients with Alzheimer’s disease as well as those with Parkinson’s disease. Decreased connectivity between particular DMN areas has also been linked to levels of rumination in depressed individuals. Further links with DMN dysregulation have been made to autism, schizophrenia, and other conditions.
The DMN is also thought to play a role, in combination with other brain networks, in key human qualities such as creativity. As a person idles and her mind drifts, the activity of the DMN may help give rise ideas that other networks then vet and process further.