Near Death Experiences (NDEs) have been reported across the world, by different cultures and throughout history. Tales of intense lights, life flashing before you and vivid emotions are commonly reported by those that have nearly kicked the bucket before pulling through.
NDEs are not an easy subject to research and as big pharma companies won’t make any money from the results, not that many scientists have run solid studies on them. A team from the University of Michigan however have recently published a study in the Proceedings of the National Academy of Sciences that adds to the small collection of info we have so far.
The team measured brain activity in nine rats as they died of cardiac arrest. It was the first study to systematically investigate brain activity after cardiac arrest. Most people had assumed that once the heart had stopped, brain activity would either diminish or disappear completely, but they found quite the reverse was true. The brain was overstimulated and hyper-excited.
In the 30 seconds following the cardiac arrest there was a large increase in gamma oscillations within the brain, in fact they found more gamma activity than within a living brain.
What Are Gamma Oscillations?
These gamma waves clock in at about 40Hz on average and were the last of the brain waves to be characterised. So what’s the significance of gamma oscillations? They feature in another field of study which is impenetrable and super tricky – the study of consciousness. Consciousness is an unwieldy jelly-like subject. It’s hard to even begin to explain what it is, let alone how or why it is. But gamma oscillations often crop up in their discussions. One of the big questions in consciousness is how the brain collates multiple sensory inputs and presents them to us as a clear, consecutive experience that we can understand. For instance, the parts of the brain that process vision, taste, smell and touch are spread throughout the brain, but when you pick up a cheese burger and take a bite all of those elements seem to come together seamlessly and without any confusion. This problem is called the “binding problem” (click here for a good description of the binding problem).
Some theorists posit that gamma waves help the brain synchronise and makes sense of the world we parade around in. The theory goes that synchronized gamma oscillations flow from the thalamus and spread across the brain 40 times a second, bringing disparate regions of the brain into perfect sync, allowing us to bring whatever we are focusing on into the foreground of our consciousness.
Evidence is hard to come by for many reasons, but one experiment in 2004 gives an interesting insight into gamma waves. They took eight Tibetan monks, and eight novice meditators and measured their brain waves whilst meditating. During normal meditation there was no difference in brain pattern, but once they were asked to generate a feeling of compassion the monk’s patterns changed significantly. Gamma oscillations were spontaneously generated at a level never seen in a healthy human before. I suppose it proves nothing about consciousness, but it might point to that often reported NDE factor – an incredibly calm sense of peace before the end.
So this new NDE study theorizes, very tentatively, that an increase of gamma oscillation in a dying brain may bring together areas of the brain and try to make sense of the strange situation of dying. Throwing up images, smells, lights and whole gamut of emotions as a kind of last ‘Hurrah’ of the crumbling organ.
As I mentioned at the start of this piece, there’s not a lot of profit to be made from these sorts of studies (at least not yet), so it may well be a long while until we’re thrown any more information about near death experiences. So this will have to do for now.
MORE SCIENCE STUFF: