Sometimes, people survive brief periods in which their heart stops beating. Ten to twenty percent of all survivors of these periods of cardiac arrest tell strange tales of vivid experiences. These near death experiences may involve feelings of profound peace, of floating free of the body, of ascending through a tunnel of light, and of meeting with a being of light. Some people interpret these experiences in religious terms, and claim them as evidence for life after death.
Some neuroscientists are, instead, trying to explain these experiences in terms of the physiology of the dying brain.
What happens in the brain during cardiac arrest has been difficult to study, and not much was known. But, in 2013 a team of researchers reported an unexpected discovery. They found that during the first thirty seconds after their heart stopped beating, dying rats exhibited an intense spike of electrical activity in their brains.
These gamma oscillations spread over the whole cerebral cortex and were highly organized. They were similar in some ways to those exhibited during heightened states of consciousness in humans. It is, of course, impossible to tell what, if anything, the rats experienced during such events.
In 2023 another research group reported similar findings in four human patients that died of cardiac arrest while electrical activity in their brain was being recorded. Two of the humans similarly exhibited intense spikes of gamma wave activity centered in areas of the brain known to be active during dreams and altered states of consciousness.
The results support the idea that near death experiences could be explainable by brain physiology. But, much further research will be needed to understand these puzzling phenomena.
Reviewer: Anil Seth, University of Sussex, Sussex, UK
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Sources
- Smithsonian Magazine - Surging brain activity in dying people may be a sign of near-death experiences
- Medical News Today - Study finds evidence of increased brain activity in people right before they die
- ScienceDaily - Evidence of conscious-like activity in the dying brain
- LiveScience - Surges of activity in the dying human brain could hint at fleeting conscious experiences
- The Guardian - People in comas showed 'conscious-like' brain activity as they died, study finds
- Science - Burst of brain activity during dying could explain life passing before your eyes
- PNAS - Surge of neurophysiological coupling and connectivity of gamma oscillations in the dying human brain
Sometimes, people survive brief periods in which their heart stops beating. Ten to twenty percent of all survivors of these periods of cardiac arrest tell strange tales of vivid experiences. These near death experiences may involve feelings of profound peace, of floating free of the body, of ascending through a tunnel of light, and of meeting with a being of light. Some people interpret these experiences in religious terms, and claim them as evidence for life after death. Some neuroscientists are, instead, trying to explain these experiences in terms of the physiology of the dying brain.
What happens in the brain during cardiac arrest has been difficult to study, and not much was known. But, in 2013 a team of researchers reported an unexpected discovery. They found that during the first thirty seconds after their heart stopped beating, dying rats exhibited an intense spike of electrical activity in their brains. These gamma oscillations spread over the whole cerebral cortex and were highly organized. They were similar in some ways to those exhibited during heightened states of consciousness in humans. It is, of course, impossible to tell what, if anything, the rats experienced during such events.
In 2023 another research group reported similar findings in four human patients that died of cardiac arrest while electrical activity in their brain was being recorded. Two of the humans similarly exhibited intense spikes of gamma wave activity centered in areas of the brain known to be active during dreams and altered states of consciousness. The results support the idea that near death experiences could be explainable by brain physiology. But, much further research will be needed to understand these puzzling phenomena.