Approximately 3% of the US population say they have had a near-death experience, according to a Gallup poll. Near-death experiences are reported across cultures and can be found in literature dating back to ancient Greece.
Near-death experiences are simply "manifestations of normal brain functions gone awry" and that many common near-death experiences could be caused by the brain's attempt to make sense of unusual sensations and perceptions occurring during a traumatic event, researchers explain. Dr Caroline Watt, said: "Our brains are very good at fooling us...The scientific evidence suggests that all aspects of the near-death experience have a biological basis."
There is a condition called "Cotard" - or "walking corpse" syndrome, where a person believes they are dead. It has been seen following trauma and during the advanced stages of typhoid and multiple sclerosis. Out-of-body experiences, where people feel they are floating above themselves, are also commonly reported. But Swiss researchers found such experiences could be artificially induced by stimulating the right temporoparietal junction in the brain that plays a role in perception and awareness. The "tunnel of light" sensation reported by those who believe they are having a near-death experience can also be artificially induced. Pilots flying at G-force can sometimes experience "hypertensive syncope" which causes tunnel-like peripheral or even central visual loss for up to eight seconds. And a US study suggested the light at the end of the tunnel can be explained by poor blood and oxygen supply to the eye. The feelings of bliss and euphoria, meanwhile, can be recreated with drugs such as ketamine and amphetamine. The paper also suggests the action of noradrenaline, a hormone released by the mid-brain, can evoke positive emotions, hallucinations and other features of the near-death experience.
"Taken together, the scientific experience suggests that all aspects of near-death experience have a neuro-physiological or psychological basis."