Thursday, November 15, 2012

Near-death experiences: A sign of life after death?

Nov 15, 2012
By Andy Ho Senior Writer

A NEW book, Proof Of Heaven (2012), made the cover of Newsweek recently.

The magazine's story, entitled Heaven Is Real, is all about a Harvard neurosurgeon who went to heaven while in a deep coma. Or so he says. One night in 2008, Dr Eben Alexander felt unwell, but by early morning he had become comatose. E. coli infection of the brain, a rarity in adults, had led the outside of his brain to be filled with pus. The brain shut down, whereupon the electroencephalogram (EEG) flatlined, showing no electrical activity.

After six days in a deep coma, even as his wife was discussing with doctors in the next room when to pull the plug, the brain-dead man suddenly woke up, tugged at the tubes and began talking. He related his experience of a "hyper-vivid and completely coherent odyssey" into another dimension while comatose, one with angels, music, beauty, love and flying on butterfly wings.

While a great yarn, it holds much in common with stories related by others who have had this "near-death experience" (NDE). In a 2001 Lancet study of 344 Dutch patients who were resuscitated after cardiac arrest, 18 per cent had had an NDE while clinically dead.

The NDE was first described by American psychiatrist Raymond Moody in Life After Life (1975). He noted 15 characteristic features such as euphoria, an out-of-body experience, going through a tunnel, rising into the heavens, encountering non-physical beings and departed loved ones, sensing a loving "Being of Light", a review of one's life and, finally, returning to the body.

In 2006, a University of Virginia (UVA) study noted that while NDE trippers were not particularly religious before the experience, it tended to cause a "spiritual transformation" so they became less afraid of death and convinced that love trumped material goods.

Critics insist that everything in the universe is grounded in material reality. So all mental processes can only come from chemical ones in the material brain. As there can be no consciousness without a functioning brain, there can't be life after death, they say.

When the heart stops, blood flow to and oxygen uptake by the brain drops to near zero within seconds, so higher brain functions stop. The EEG shows the brain's electrical activity slowing down within six to 10 seconds, then flat-lining within 10 to 20 seconds. Yet over 100 cases of NDEs occurring specifically during cardiac arrest when the EEG has flatlined have been reported in at least four published studies.

So how could a coherent, highly structured experience like this arise from a clinically dead brain?

Critics say, first, that the EEG is just picking up electrical activity in the outer part of the cerebral cortex (grey matter). So when it flatlines, the inner part of the brain could still be active.

However, the issue is not if there is activity at all but whether it is of the kind needed to produce these vivid trips. In particular, the hippocampus, the brain region which forms memories, is especially sensitive to oxygen deprivation, so there should be no memory of the NDE in the oxygen-starved brain. Thus, any putatively residual brain capacity undetected on EEG when the brain is oxygen-deprived doesn't suffice to explain the complex information processing that seems to be occurring within an NDE.

Secondly, critics say that NDEs don't actually occur while the brain is already shut down. Instead, they may be occurring just before it shuts down or just as it is coming out of a shutdown. However, most cardiac arrest patients, on recovering consciousness, are notably confused about or amnesic of the happenings just before and just after the arrest.

By contrast, NDEers commonly report having extra-clear minds during the trip, which are thus hyper-vivid. In a 2010 study, 75 per cent or more of NDEers described their minds during the trip as clearer, faster and more logical than usual. This suggests that complex cognition and memory formation occur during an NDE.

Finally, critics note that studies show sincere people who simply imagine a specific experience can form false memories. Indeed, Dr Moody's 15 features seem to recur in NDE accounts. His 1975 book, which sold 10 million copies, may well have subsequently coloured many an account/false memory.

But a 2006 study compared 24 NDE accounts collected before 1975 against 24 accounts collected after 1975. The latter were found to differ in only one of Moody's 15 features, reporting more often the tunnel phenomenon "which other research has suggested may not be integral to the experience". Thus NDEs may be more than false memories of or imaginative reconstructions by some people.

But why don't all clinically dead patients who are then successfully resuscitated report NDEs? A 2004 UVA study found that NDEers were more likely to have EEG features that resemble those found in epilepsy in the temporal lobes.

These are the parts of the brain at the temples which are active in religious experiences. Stimulating them experimentally can cause hallucinations, memory flashbacks and out-of-body sensations. Thus it may be that people with temporal lobes that function in a specific manner are more likely to have NDEs.

Bottom line: Do NDEs prove consciousness persists after death? Those who say "yes" think that the mind is more than just the brain, the twain being separable entities. Those who say "no" insist that the mind is just the brain. Yet both parties may be jumping the gun since how consciousness emerges from the physical brain - a conundrum that philosophers have dubbed "the hard problem" - is not known. If so, asking if consciousness can persist after death puts the cart before the horse. Whether heaven is real or not, the NDE isn't really proof either way.

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