A variety of explanations might also account for reports by those dying of meeting the deceased.
Parkinson's disease patients, for example, have reported visions of ghosts, even monsters. Parkinson's involves abnormal functioning of dopamine, a neurotransmitter that can evoke hallucinations.
Mobbs and Caroline Watt at the University of Edinburgh detailed this research online August 17 in .
In addition, research now shows that a number of medicinal and recreational drugs can mirror the euphoria often felt in near-death experiences, such as the anesthetic ketamine, which can also trigger out-of-body experiences and hallucinations.
Ketamine affects the brain's opioid system, which can naturally become active even without drugs when animals are under attack, suggesting trauma might set off this aspect of near-death experiences, Mobbs explains.
Altogether, scientific evidence suggests that all features of the near-death experience have some basis in normal brain function gone awry.
Moreover, the very knowledge of the lore regarding near-death episodes might play a crucial role in experiencing them—a self-fulfilling prophecy.