August 13, 2013, 12:31 PM —
Image credit: Flickr/KIWANJA
There long has been a debate about "near-death experiences," in which people whose hearts momentarily stop beating report seeing brilliant lights, long tunnels, dead relatives and other visions, report floating above their own bodies, etc.
The people who have had and believe in those experiences insist they're quite real, while skeptics argue that they either are fabricated or meaningless hallucinations.
Now science is weighing in with evidence that brain activity continues after cardiac arrest, and actually may increase immediately after a heart stops beating.
In an experiment with nine lab rats, researchers at the University of Michigan Health System determined that "shortly after clinical death, in which the heart stops beating and blood stops flowing to the brain, rats display brain activity patterns characteristic of conscious perception," the university said in a statement:
Researchers analyzed the recordings of brain activity called electroencephalograms (EEGs) from nine anesthetized rats undergoing experimentally induced cardiac arrest.
Within the first 30 seconds after cardiac arrest, all of the rats displayed a widespread, transient surge of highly synchronized brain activity that had features associated with a highly aroused brain.
About one in five heart attack survivors report near-death experiences, which they invariably describe as intense and surreal.
“We reasoned that if near-death experience stems from brain activity, neural correlates of consciousness should be identifiable in humans or animals even after the cessation of cerebral blood flow,” said lead study author Dr. Jimo Borjigin, associate professor of molecular and integrative physiology and associate professor of neurology at the University of Michigan Medical School.
“We were surprised by the high levels of [brain] activity,” said study senior author Dr. George Mashour, assistant professor of anesthesiology and neurosurgery at the U-M. “In fact, at near-death, many known electrical signatures of consciousness exceeded levels found in the waking state, suggesting that the brain is capable of well-organized electrical activity during the early stage of clinical death.”
Results of the research were published Monday in the Proceedings of the National Academy of Sciences.