NRSC 4132 Blog

We have all heard the theories of seeing a bright light or your life flashing before your eyes right before you die. In fact, accounts of these near-death experiences can be traced back to literature of ancient Greece. Most theological doctrines share the idea that death is a passing to an afterlife, an eternal utopia where we are reunited with loved ones. Interestingly, 3% of Americans declare to have had a near-death experience [1], and their accounts have recently been discussed in several books. These books, however, tend to leave out physiological explanations for these experiences and rely solely on paranormal explanations.

The Medical Research Council of Cambridge and University of Edinburgh took it upon themselves to research the neurological events behind these notions. They found that contrary to popular belief, there is actually nothing paranormal about these experiences. Instead, near-death experiences are the manifestation of normal brain function gone awry during a traumatic, and sometimes harmless, event [2].

In order of occurrence, the basic features of near-death experiences include awareness of being dead (50%), meeting with deceased people (32%), moving through a tunnel (31%), and having an out-of-body experience (24%) [3]. Only 56% of those who had a near-death experience associated it with positive emotions, which is contrary to the belief that feelings of euphoria and bliss are associated with these experiences.

The following are scientifically-based explanations on these peculiar experiences. Cotard syndrome is a documented disorder characterized by the feeling that one is dead. It has been associated with the parietal cortex and the prefrontal cortex, and just like the near-death experience equivalent, it is likely an attempt for the brain to make sense of a strange experience the patient is having. Out-of-body experiences are common during REM sleep, and results from a failure to integrate multisensory information from one's body, which results in the disruption of self-representation. A tunnel of light can be explained by visual activity during retinal ischemia, which is when the blood and oxygen supply to the eye is depleted. It has been to feelings of extreme fear because the same sensation has been reported by pilots flying at G-force. As far as meeting deceased people, several neuroscience studies have proved that brain pathology can lead to visions of souls of the dead, angels or a religious figure that are prevalent in fiction and personal accounts. Examples are hallucinations of Alzheimer's or Parkinson's disease, and patients with abnormal dopamine function. Theoretically, many hallucinations are due to brain structures over-compensating near damaged areas or making sense of noise from damaged areas.

Additionally, the fact that the drug ketamine often mimics these experiences including hallucinations, out-of-body experiences, and positive emotions such as euphoria, dissociation, and spiritual experiences further supports the position these accounts are due to neurophysiological parameters, not paranormal phenomenon.

Obviously, further evidence is required if the ideas such as these will ever be fully demystified by the reliable realm of science. Though it may come as a disappointment to some (and others may even refuse to accept it), it is important that these neurobiological-based findings are spread.

[1] Schmied, I. et al. (1999) Todesna¨heerfahrungen in Ost- und Westdeutschland eine empirische Untersuchung. In Todesna¨he: interdisziplina¨re Zuga¨nge zu einem auergewo¨hnlichen Pha¨nomen (Knoblaub, H. and Soeffner, H.G., eds), pp. 217250, Universita¨tsverlag Konstanz

[2] Article Source: http://download.cell.com/trends/cognitivesciences/pdf/PIIS1364661311001550.pdf?intermediate=true

[3] van Lommel, P. et al. (2001) Near-Death experiences in surviviors of cardiac arrest: a prospective study in the Netherlands. Lancet 358, 20392045