By Douglas Quenqua, New York Times, August 12/13, 2013

A surge of brain activity in dying rats may hold an explanation for the vivid, realistic visions experienced by some human victims of cardiac arrest, researchers say.

About 20 percent of such patients say they have experienced lucid, lifelike hallucinations after clinical death, often described as visions of an afterlife or other supernatural scenarios. Seeking a physical explanation for the phenomenon, scientists from the University of Michigan induced cardiac arrest in nine rats and monitored their brain activity with an electroencephalograph.

Within 30 seconds of clinical death, each of the rats displayed low-amplitude but very high-frequency waves indicative of a highly aroused brain. Activity associated with information processing was eight times what is typically found during a conscious, waking state. Activity associated with sensory processing was five times as high.

“You take away the oxygen, take away the glucose, and at least temporarily there’s this heightened activity,” said Jimo Borjigin, an associate professor of physiology at the University of Michigan and lead author of the study, which was published in Proceedings of the National Academy of Sciences [....]