Near-death experience

A near-death experience (NDE) is the sensation of an out-of-body experience reported by a person who nearly died or who was clinically dead and revived. They are somewhat common, especially since the development of cardiac resuscitatation techniques, and are reported in approximately one-fifth of persons who experience clinical death.

Typically a near-death experience involves the sensation of floating above one's body and seeing the surrounding area, followed by the sensation of passing through a tunnel, meeting deceased relatives, and encountering a being of light. There have also been accounts of patients seeing things they apparently could not have seen had they not been out of their bodies.

Although near death experiences have been taken by some as evidence of an afterlife, there are no known elements of NDEs which cannot be explained in natural terms. There have been numerous experiments in which a random message was placed in a hospital in a manner that it would be invisible to patients or staff yet visible to a floating being, and thus far, no person experiencing a near death experience has been able to reproduce the message. In addition, it has been pointed out that children who experience NDE's sometimes report seeing their living friends and playmates in their visions, contrary to the implication that the persons seen during the experience are the souls of dead loved ones.

Nevertheless, the subjective reality of NDEs is well documented. One scientific hypothesis that attempts to explain NDEs was originally suggested by accounts of the side-effects of the drug Ketamine (see link to Dr. Karl Jansen below). Ketamine was used as an anesthetic on U.S. soldiers during the Vietnam War; but its use was abandoned and never spread to civilian use because the soldiers complained about sensations of floating above their body and seeing bright lights.

Further experiments by numerous researchers verified that intravenous injections of ketamine could reproduce all of the commonly cited features of an NDE; including a sense that the experience is "real" and that one is actually dead, separation from the body, visions of loved ones, and transcendant mystical experiences.

Ketamine acts by blocking the receptor for the neurotransmitter glutamate. Glutamate is released in abundance when brain cells die, and if it weren't blocked, the glutamate overload would cause other brain cells to die as well. In the presence of excess glutamate, the brain releases its own glutamate receptor blocker to defend itself; and it is these blockers Dr. Jansen (amongst others) hypothesize as the cause of many NDEs.

Critics of this hypothesis point out that although some aspects of the experience may be similar, not all NDEs exactly fit the ketamine experience; and that while it might be possible to chemically simulate the experience, this does not refute the possibility that true NDEs have a spiritual component. As even Dr. Jansen notes:

Claims that NDE's must have a single explanation (e.g. Ring, 1980), or that a scientific theory must explain all of the experiences ever given the name of NDE (e.g. Gabbard and Twemlow, 1989) are difficult to justify.

Dr. Raymond Moody[?] has chronicled and studied many of these experiences in his books:

• The Last Laugh
• Life After Life
• Reflections on Life After Life[?]

Another researcher in the field is Dr. Kenneth Ring.

External link

• Near-Death Experience Research Foundation (NDERF) (http://www.nderf.org/)
• The Ketamine Model of the Near Death Experience: A Central Role for the NMDA Receptor, Jansen, Karl (http://www.mindspring.com/~scottr/nde/jansen1)
• Jansen, K. L. R. (1996) Using ketamine to induce the near death experience: mechanism of action and therapeutic potential. Yearbook for Ethnomedicine and the Study of Consciousness (Jahrbuch furr Ethnomedizin und Bewubtseinsforschung) Issue 4, 1995 (Ed.s C. Ratsch; J. R. Baker); VWB, Berlin, pp55-81. (http://leda.lycaeum.org/?ID=9260)