Stories of the near-death experiences, or NDEs, of coma patients have been collected by Steven Laureys down the years: “Some people will report having had an out-of-body experience, having seen a bright light or being passed through a tunnel; all well-known elements of the famous near-death experience,” he explains.
The patients do seem to come back happier and no longer fear death, according to Laureys, whose team has studied 18 coma survivors and a similar number of controls. They compared people’s memories of NDEs with memories of intense real-life events like marriages and births and also with recollections of dreams and thoughts – events that did not occur in reality. The memories of NDEs are “even more real than real,” he says.
The experiences are clearly hallucinations of some kind, though there are still those who cling to the mystical idea that they suggest human consciousness can somehow function independently of the brain, a Victorian idea that the ‘spirit’ can gaze down on the body as it departs (presumably for heaven), before returning to tell the tale. Laureys points out that not one patient has recalled seeing any of the targets that have been specially placed high up and out of normal view in operating theatres to test this far-fetched idea.
However, we do know that NDEs are the product of a distressed brain and we are even beginning to understand how they are produced. A study by Jimo Borjigin and colleagues at the University of Michigan recorded EEG activity directly from the brains of nine rats, which had been given – under heavy anaesthesia – a lethal injection of potassium chloride into the heart. Between 12 and 30 seconds after cardiac arrest, the rats’ brains became surprisingly active, ringing with highly coherent neural oscillations for a 20-second interval after the heart and lungs stopped working.
Whether this reflects a state of heightened consciousness, as some have claimed, is a matter of debate: they are rats, after all. Nonetheless, Laureys believes this paradoxical surge in brain activity does mark an interesting insight into consciousness at the end of life. More answers will come when, inevitably, a dying patient happens to be inside a scanner when the last trace of consciousness ebbs away.
Professor Laureys and his colleagues would like to hear from any readers who have had a near-death experience and are willing to share their story. Email them at firstname.lastname@example.org.