Definition Day: Default Mode Network & Ego Dissolution
Psychedelic coverage throws around a lot of jargon fast, so twice a week we're slowing down on two terms at a time.
Default Mode Network (DMN): the brain network active during self-referential thinking — mind-wandering, autobiographical memory, the running mental narrative about yourself. Neuroscientist Robin Carhart-Harris's "entropic brain" hypothesis proposes psychedelics work partly by collapsing this network's normal organization. When his team first scanned brains on psilocybin, they expected to see more activity and instead found a significant drop-off — the opposite of the prediction they went in with, and part of why the DMN became central to modern psychedelic neuroscience.
Ego Dissolution: the temporary loss of the felt boundary between self and everything else, one of the most commonly reported effects at higher psychedelic doses. Researchers measure it with the Ego-Dissolution Inventory, an 8-item scale validated in 2016. Scores on it rise with psychedelic dose but not with cocaine or alcohol dose — part of why researchers treat it as a specific, measurable effect rather than generic intoxication.
Full entries, plus 97 other terms, are in our Encyclopedia.