If you’ve ever heard someone recount a near-death experience, you know it can be chilling. They speak with absolute conviction about the sensation of rising out of their body, seeing their surroundings from above, and then moving rapidly to a bright yet soothing light — among other common themes.
Is there a scientific explanation for the fact that so many people who have gone to the brink have the same perceptions? This week researchers reported on studies of rats that showed a huge surge in brain activity after the heart stops beating. The study found a spike in high frequency brainwaves called gamma oscillations, to even higher levels than exist in alive, awake rats. The brain activity was consistent with perception of visual activity, conscious processing, and heightened communication among different parts of the brain. Then, of course, the rats die and brain activity ceases.
The study has provoked a lot of speculation about whether the rat experience is replicated in humans, and whether it could explain the vivid encounters reported by those who have had a close brush with death. The theory is that the surge in brain activity after the oxygen flow stops produces the sharp visual sensations and altered sense of time that are reported by many survivors. As the Washington Post reports, however, there is skepticism and dispute within the scientific community about whether the rat study can tell us much about the human experience and can explain the uncanny similarity of the experiences reported by people of different cultures and religious faiths.
We know that there are many people who have had a near-death experience and who believe that what they saw and felt was real, deeply meaningful, and had an intensely spiritual, even cosmic significance. Entire websites are devoted to discussing such experiences and large conventions are held so that survivors can share their perceptions. Many people, including those who have just lost a loved one, find great comfort in hearing about these experiences.
What really happens when we die? It is the eternal question, and one that science probably cannot answer. We’ll just have to find out when it happens to us.