Several years ago, I worked with a college tutor called John, who had a heart transplant in 1992. During the operation, he was surprised to suddenly find himself awake and alert, looking down on his own body from above. He could see the surgeon and the nurses performing the procedure, and sensed from their behaviour that there was an emergency; he could see them rushing around, trying to take action to save his life. He was also surprised to find that he could hear classical music in the operating theatre. He felt himself floating further away from his body, into a darkness which felt strangely peaceful and welcoming. Then he encountered his father, who had died a few years earlier. His father seemed equally surprised to encounter him, and told him, “You shouldn’t be here – it’s not your time yet.” Then John felt himself moving back down towards his body, and lost awareness again. The next thing he knew, he was awake in recovery. Shortly afterwards, he asked the surgeon, “How come you were playing classical music in the operating theatre?” The surgeon was amazed that he knew this, since he had been unconscious when they turned the music on.
Last September, the results of an international study (led by Dr. Sam Parnia at the State University of New York) of more than 2000 cardiac arrest patients were published. This found that 40% reported some form of awareness during the time when they were clinically dead, when their hearts had stopped beating and their brains had shut down (1). But how can we be sure that the awareness they reported actually stemmed from the period when they were “dead”? you might ask. Perhaps it was just a kind of hallucination which actually took place just before their brains shut down, or just when they were becoming active again.
However, as was the case with my colleague John, some patients reported a sensation of leaving their bodies and observing their own operations from above. They were able to describe actual events during the procedure – such as the actions of the nurses, or the instruments used by their surgeons, and the sounds of machines – which were later verified. (One man accurately described the appearance of the doctors who attended to him, and also the automated external defibrillator that restarted his heart).
Once a person’s heart has stopped beating, the brain shuts down within 20-30 seconds. So can how a person continue to be conscious during this period? Since the idea that consciousness could continue without brain activity appears highly unlikely to many people, other explanations have been put forward. First of all, can we really rely on the reports of people who believed they saw their own operations from above and described details about them? Perhaps they were simply constructing an image of what they expected from the operation, including the doctors, nurses, instruments and procedure.
And in any case, can we really be sure that the brain is completely “shut down” in these periods? Even if it doesn’t show any sign of activity shortly after the person’s heart stops beating, does that mean there is no activity at all? Perhaps there is brain activity at a very low level which is difficult to detect.
However, even if this is plausible, there would still be the problem of explaining how a very low degree of brain activity (so low that it is undetectable) could give rise to an experience of such complexity and intensity. In near-death experiences, people often report feeling much more alert than normal, with a very clear and intense form of awareness. It is difficult to see how a very low level of brain activity could generate this. If anything, there would surely be a form of consciousness which was much more vague, confused and dim.
Perhaps the best way of explaining NDEs in material terms is – as touched on briefly above – to see them as unusual experiences which occur shortly before the brain becomes inactive. Perhaps they are simply a kind of hallucination generated by a dying brain. For example, It has been suggested that cerebral anoxia – a lack of oxygen to brain tissue – causes many of the characteristics of NDEs. It results “cortical disinhibition” and intense, uncontrolled brain activity. The vision of tunnels and lights can be linked to disinhibition in the brain’s visual cortex. At the same time, the intense sense of well-being could be caused by the release of endorphins.
However, there are also problems with these explanations. You would expect intense, uncontrolled brain activity to result in crazy, chaotic experiences, but NDEs are usually very serene and well integrated experiences – certainly not what one would associate with ‘disinhibition’ and over-stimulation. In fact, cases of cerebral anoxia usually do feature bizarre and random mental activity, completely dissimilar to NDEs.
You would also expect uncontrolled brain activity to result in a very wide range of different experiences, as varied and different as dreams. However, as we have seen, the majority of people who report this continuation of consciousness report the same “core” experience (according to Pim van Lommel, 66% of NDEs included the core characteristics.) An additional (although not as significant) point is that, subjectively, people feel that, far from being illusory or hallucinatory, NDEs are much more intensely real than normal consciousness. They carry an intense sense of clarity and revelation which is very different to most hallucinatory experiences.
Another suggestion is that NDEs are caused by the release of large amounts of DMT in the brain close to the point of death. The basis of this explanation is the similarity of some DMT experiences (when it is taken as a drug) to NDEs. However, in actual fact, studies have shown that only a small percentage of DMT experiences have any strong similarity of NDEs. If it was the source of the experience, one would expect a stronger relationship. Other suggestions have been that NDEs are associated with high concentrations of carbon dioxide, altered serotonin activity, temporal lobe paroxysms, REM sleep patterns…
The wide variety – and lack of consensus – of these attempts at explanation is striking, and hints that the the physicalist approach may be in itself flawed. As Irwin and Watt have put it, ‘It is fair to say that no current neurophysiological or psychological theory of NDEs is satisfactory.’(2)