Default Mode Network (DMN)

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The default mode network (DMN) is a brain network connecting regions that show higher activity during rest and decreased activity during tasks requiring sustained, goal-directed focus. The DMN supports internally directed cognition, including self-reflection, memory retrieval, reminiscing, planning, daydreaming, and mind-wandering. Key regions include the medial prefrontal cortex, posterior cingulate cortex, and angular gyrus.

The DMN plays an important role in identity, meaning-making, and mental time travel, but when overactive or poorly regulated, it can contribute to rumination, worry, and difficulty shifting attention outward. Altered DMN activity has been linked to depression, anxiety, and schizophrenia, and is implicated in attention difficulties seen in ADHD and autism.

Emerging research suggests variations in DMN function may also relate to patterns of self-focus — such as increased local efficiency associated with grandiose narcissism or links between vulnerability and oxidative stress — though these findings are still being explored. The DMN is part of a broader system of interacting networks, including the salience network, which helps determine what captures attention and when the brain shifts between internal and external focus.