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Scientific explanations of life after death experiences
A lot of people narrate strange experiences which may not be explained on the basis of the known and recognized principles of science. I had a young patient once who claimed that she had lived her previous life in a house located in Kolkata, India, a city that she is on record never to have visited. The description of the house was verified to the surprise of everyone concerned — even her parents.
As a practising psychiatrist I once met a young man who claimed to predict anyone’s future by shaking hands with that person. Apparently his claim was true.
A senior professional confided in me that she had the ability to call the spirits and communicate with them. Instances have been cited of people who foresaw events about to happen in their lives and in others’.
But does human brain really have the ability of premonition? There are no adequate scientific explanations but it is said that we use less than 15 per cent of our brain and, as such, 85 per cent of its faculties remain unutilized. So what would happen if one could use this potential? However, none of these cases this was ever proved scientifically.
Can one predict future, or speak about a past life? This is a big question mark. In the Hindu religious belief, one has to live through seven lives; the spirit changing the body seven times, until mukti or nirvana is achieved. The question is that if it’s true, then why doesn’t it happen to every soul? Why can’t everyone remember their previous lives.
An explanation given by some scientists is that the cells of the body of a dead person remain suspended in the surroundings for a long time. If these cells are inhaled by a pregnant woman passing by, they may get embedded in the foetus that is in the developmental process. And as such these cells get programmed in the nascent memory system.
Other scientists try to explain the phenomenon with the theory that people can develop amazing brain capabilities through mind exercises, hence acquiring these fascinating powers.
Another strange feeling, called the “near-death experience” has also been described by many in an interesting way.
People who have survived cardiac arrest, coma, violent accidents or surgical procedures have been quoted to have felt as if they came out of their body and witnessed things around their prostrate body, or as if they were moving through a dark tunnel. Others mention experiencing intensely powerful emotions ranging from bliss to terror, encountering a light which is usually described as golden and white, something magnetic and attractive.
Some people state receiving a message suggesting that it was not their time yet. They cite meeting deceased loved ones, or reaching up a boundary, a cliff, or a fence, with water or some other kind of barrier that could not be crossed — as if one is destined to return to life. Most of these strange experiences are described as pleasant but sometime they are quite frightening.
Questions have been raised about scientific interpretation of such experiences. It is said that low oxygen levels to brain and retina may produce a light and the tunnel as the lower level of the brain remains functional even in coma, and may cause these visions.
It was also proposed that they may have been caused by psychological dissociation. That the NMDA receptor block rate in the hippocampus would close access to sensory information and cause the brain to generate an alternate internal reality. This alternate reality induced by ketamine involves heavy dissociation as exemplified by consistent reports of people feeling detached from their bodies. The emotional centres of the brain become reactivated as a result of revival efforts. They begin signalling strong emotions, which the cerebral cortex is not yet able to properly interpret. Subsequently, intense respiration causes the cardiovascular system get a large quantity of oxygen circulated through the body. As a result the brain begins to get more oxygen than usual and starts functioning abnormally faster.
Interestingly, this is similar to the emotional “startle” response that causes newborns to begin breathing on their own (sometimes the doctors have to slap the newborns to startle them into starting to breathe).
The “tunnel of light” is explained to be an individual’s response to reactivation of the brain due to revival efforts leading to an increased cerebral blood flow. As oxygen and nutrients become more readily available to the brain, the vision system may begin to resume function though erratically. This has supporting evidence in the centrifuge experiments on fighter pilots who report tunnel vision when they have reduced blood flow to the brain
Still another explanation is that oxygen-starved sensory neurons in the eyes may begin to fire at random. Since these sensory neurons are more densely packed near the centre of the eye, the person experiences a bright light at the center of their vision field which grows dimmer towards the periphery thereby creating a tunnel-like image.
Finally, there is experimental evidence showing that the tunnel of light sensations can be attributed to certain neuro-chemical pathways activated during stress. Many of those people who have undergone a near-death experience have told that they have had positive changes in their lives.
Some pertinent questions which could not have been answered are: (1) Are these experiences the same as being experienced by a person who is dead? (2) Are the dead people in contact with the living people in some way? (We need to exclude the psychotic hallucinations.) (3) What is the mystery related to the memories of the previous lives? (4) What about the soul or the spirit? Is it a form of energy? In what form does it exist and move? (5) What are the parameters by which one can develop mental powers and acquire control over the body? (6) Can we, to any extent, get an insight into “life after death”? Or is it that once a person is dead, there is a total blackout.
Extensive research is being done to answers these questions.
The writer is professor and head of psychiatry at the Hamdard University Hospital, Karachi
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