One of the Cognitive ghosts discussed in the The Rest Is Science episode “Cognitive Ghosts”.
What it is
The reported sensation that, at the moment of near-death or actual death, your whole life flashes before your eyes — a flood of memories, sometimes described as a rapid life review. Long dismissed as a cliché or trope, it now has at least a tentative neurological basis.
What’s happening in the brain
Two complementary ideas come up. First, a survival search: faced with mortal danger, the brain may rapidly ransack memory for any past experience that could help it escape the threat. Second — and more concretely — the dying brain may replay memories as a byproduct of its final bursts of activity. There’s an important caveat the hosts raise: because the “life flashing” idea is such a well-worn cultural trope, it may also shape how survivors interpret and report whatever they actually experienced.
References from the show
- The hosts describe a remarkable case: an EEG recording captured by accident as an elderly patient died — this is the Zemmar et al. (2022) study (Frontiers in Aging Neuroscience). An 87-year-old man with epilepsy had a cardiac arrest while being monitored; in the ~30 seconds before and after blood flow stopped, his brain showed a surge of gamma oscillations in patterns strikingly similar to those seen during memory retrieval and dreaming — the first-ever EEG of a dying human brain.
Links
- Surges of activity in the dying human brain — Scientific American
- Surge of gamma oscillations in the dying human brain — PNAS / original study
Related
- End-of-life dreams and visions — the other “edge of death” ghost in the episode
- Déjà rêvé · The Third Man Factor
- Cognitive ghosts