Does a rat’s life flash before its eyes before it dies? This is precisely the question Professor Jimo Borigjen and her team attempted to address in their recently published research into the phenomena of near-death experiences. Roughly 20% of heart attack victims who have experienced clinical death can recount a near-death experience that they described as including highly lucid visions of their soul leaving their body, and feelings of extreme bliss and happiness. Some even report meeting dead relatives and even religious figures.
When we talk about scientifically investigating this, you would be forgiven for thinking of the 1990 film Flatliners, where Kiefer Sutherland leads a team of rogue young medical students that includes Julia Roberts and Kevin Bacon, into a series of somewhat improbable, dark experiments involving induced death followed by resuscitation in order to experience ‘the other side’. But beyond Hollywood movies, the fact that these experiences occur so regularly and have been reported across cultures has convinced some scientists to take near-death experiences seriously as a subject for scientific investigation.
Several ideas about the biological processes that underlie near-death experiences have been put forward. Some have proposed that damage to retinae due to hypoxia results in a tunnel vision similar to that reported by pilots exposed to high-G manoeuvres. Others suggest that the near-death experience is a result of changes in blood chemistry or alterations in levels of brain chemicals such as glutamate or dopamine. Epilepsy-like activity in the temporal lobe – a brain region associated with vivid hallucination – as well as psychological explanations regarding our expectations of the afterlife, have also been offered.
The big question, however, is whether or not the brain is capable of generating the kind of lucid hallucination associated with a near- death experience when the blood supply to the brain has been cut off. Even if it can, what’s the method by which it happens? Can we explain this strange phenomenon in terms of brain function? Professor Borigjin and colleagues hypothesised that if the brain is producing a near-death experience, then scientists should be able to detect brainwaves that indicate consciousness after a heart attack.
Borigjen and colleagues set up an experiment where they artificially induced heart attacks in rats and simultaneously measured the animal’s brainwaves. What they observed was a brief spike in brain wave activity; specifically brain waves known as gamma oscillations. These are the waves believed by some scientists to underpin consciousness, because they appear to arise when we attempt to recall memories or are being consciously aware of our surroundings. The way these brain waves were organised in the rat brains after cardiac arrest might suggest a heightened level of consciousness. Importantly these findings were also seen when animals were killed by carbon dioxide asphyxiation, suggesting the results were not caused by pain or other specific aspects of cardiac arrest.
The research does however come with numerous caveats, the most obvious of which is that we can never really know what’s going on in a rat’s mind. We don’t know if they experience consciousness in the same way that humans do. Furthermore, we aren’t certain that gamma brain waves are only associated with consciousness. We therefore can’t conclusively say that the rats in the study were experiencing a near-death experience, but that is not to say that the study is meaningless.
What is important about this study and generating the controversy is that it appears to have located in the human brain the processes that could possibly underlie the near-death experiences. Many have argued the lucidity of the near-death experiences reported by those who have recovered from heart attacks as being so intense that they could not possibly be the product of the human mind. Some, such as Howard Storm, author of the controversial best seller My Descent into Death, have gone so far as to say that near-death experiences offer a proof of heaven, hell and life after death. The lastest results appear to provide a start, at least, into a rational understanding of this phenomena.