Near-death experience: in our head?

 About death, life and brain.

It is called near-death experience (NDE) and for some, it is a proof that afterlife exists. Well-known and yet mysterious, near-death experience is a weird phenomenon. From a physiological point of view, your heart stops beating but you are not dead. But from the person’s point of view, strange things happen.

NDE subjects relate different stories about their sensation at the time of the event, but there are common points. First, they all feel an impression of leaving their body and observing it while it’s lying on the bed. Then a long tunnel appears with a shinning white light.  They feel an overwhelming sense of happiness, love and peace. As introduced, some people believe it is a proof of the afterlife. Well, scientists like to test, discover and explains things we do not understand, especially when they involve our brain and our death. A recent article of the Washington Post sheds some light on new experiments on rats to understand what really is happening when someone is having a NDE. And the results, even if they need to be proved on humans, are still quite impressing. One could ask why rats? What does these little animals have in common with humans?

 

Well, there are a couple of reasons: first, rats have physiological similarities with humans (both mammals). Second reason, it is complicate to make this experimentation on human since number of NDE is very low and third, we know someone had an NDE only when that person reports its story. Of course, this problem happens when rats too (they can’t tell it beforehand either), but the solution to the problem is explained below. To solve this mystery, scientists from the University of Michigan tried to reproduce NDE on rats. They induced a cardiac arrest to the rats and with an EEG – Electroencephalogram – observed their brain’s activity. Surprising results arose as the EEG caught more and more electrical signals. Within thirty seconds after the heart stopped, the EEG showed a surge of synchronized brain activity in areas related to consciousness and visual activation. In fact, patterns were higher than ones observed during normal awaken state. As the author said, they “may have been having the rodent version of a near-death experience».

Of course, you can’t ask a rat whether or not he was having a NDE, but such high brain activity could be a signature of it. According to Dr Borjigin – in charge of these experiments – sensation felt during NDE are the results of firing neurons in specific brain areas. This white light is also a consequence of these brain patterns – spikes of neurons firing in the visual cortex. Nevertheless, this study has to be taken carefully. Experimenters are hesitating to officially draw a connection between NDE and a surge of brain activity. Tests have only been conducted on rats, not on humans and even if results are shocking, it can’t be generalized until tested on humans. Moreover, the lack of oxygen because of the heart stopping could also cause a “shock-to-the-system” response by brain cells and therefore create similar patterns to those seen on the EEG. Yet, the interest for such a study lies beyond NDE. Little researches has been made on the dead brain and what happens during few minutes after a brain dies. Fundamental research is starting to dig into this question and this experiment reveals more about our brain functioning when it comes to it last activity.

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