When you die, your life passes you by. At the end of a dark tunnel, a very bright light appears that you are moving towards. You leave your own body and look at yourself from another place in space. These experiences have been made by people who were very close to death. It doesn't matter whether those affected are young or old, or whether they are religious or atheist, as the Heidelberg psychiatrist Michael Schröter-Kunhardt, chairman of the German section of the "International Association for Near-Death Studies", reported to the "Deutsches Ärzteblatt" in 2003 . Nationality, education or gender also did not influence appearance and form of experiences.
Schröter-Kunhardt has studied more than 230 cases of near-death experiences. The remarkable thing about the NDEs (near death experiences) is that everyone sees almost the same pictures and talks about similar experiences, he noted. Accordingly, 89 percent described a "feeling of calm, peace or well-being", 77 percent described a "bright light". 61 percent had the feeling of being outside the body and seeing it – for example from above – during their NDE. According to the psychiatrist, 47 percent of the patients reported the tunnel phenomenon, and 30 percent saw events in their past play out in front of them like a movie.
A small study measuring the brain activity of dying people could now help to better understand and explain the phenomenon of near-death experiences. It also sheds new light on the surprisingly unsolved question of how we die, said Jimo Borjigin of the University of Michigan, who was involved in the research.
For the study, published Monday in the Proceedings of the National Academy of Sciences, Borjigin and her team examined four people who were in a coma. The patients were all on life support equipment, wore EEG caps, and had no chance of survival. The Caps continuously monitored their brains' electrical signals before and after the doctors removed the ventilators, during the last detectable heartbeat, and until all brain activity ceased.
Seconds after the ventilators were removed, the neuronal activity in high-frequency patterns, the so-called gamma waves, increased drastically in the brains of two patients, writes the “Science Magazine” about the study results. This burst of activity continued even after the heart stopped beating. In one of the patients, the production of these gamma waves increased three hundred times the previous levels in the moments before death. They had reached a level higher than that found in normal brains in fully conscious people.
Other studies have found the same pattern when a healthy person is actively recalling, learning, or dreaming. Some neuroscientists have linked these rashes to consciousness.
Gamma waves can be a signal that different brain regions are working together to combine different sensory inputs into one conscious perception of an object — for example, the sight, smell, and sound of a car, explained Ajmal Zemmar, a neurosurgeon at the University of Louisville. the magazine. How the brain does it is "one of the greatest mysteries in neuroscience". But the observation of the same gamma waves in the dying suggests that there is a biological mechanism that causes the brain to replay memorable events in the final moments of life. Zemmar had previously detected similar gamma waves in a person who died of a heart attack while having their brain monitored for seizures.
Borjigin's team also discovered increased electrical activity in their brain studies in what's known as the temporo-parieto-occipital junction, which is believed to be involved in consciousness and is activated during dreams, seizures and out-of-body hallucinations. The researcher believes that the burst of brain activity is part of a survival mode that the organ enters when it is deprived of oxygen. Studies on animals that have suffered brain death have shown that the brain releases numerous signaling molecules and generates unusual brainwave patterns to revive itself even as it shuts down the outward signs of consciousness: "It closes the door to the outside world and takes care of it internal affairs because the house is on fire."
'This work is really important for the research field and consciousness research in general,' commented biomedical scientist Charlotte Martial from the University of Liège on the new mini-study. The scientist, who studies NDEs herself, assured Science Magazine that only two of the four patients examined by Borjigin showed gamma activity. Finally, not all near-death survivors reported memories or out-of-body experiences.
However, the authors themselves warned against deriving general statements from their study due to the small sample size. They also pointed out that it was not possible to establish a causal relationship between their test results and the NDEs described above, since the four patients had died and could no longer be asked about their experiences of dying.
"We are unable to establish correlations between the observed neural signatures of consciousness and a corresponding experience in the same patients in this study," the researchers wrote. "However, the observed results are definitely exciting and provide a new framework for our understanding of the latent consciousness in the dying human being.
Borjigin hopes to work with other medical centers to research the brain activity of the dying and thus corroborate their findings. Finding answers about how the dying process works would be crucial, neurosurgeon Zemmar told Science Magazine. Because "death is a kind of mystery - we don't really know what it is".
Quellen: "Surge of neurophysiological coupling and connectivity of gamma oscillations in the dying human brain", "Science Magazine", "Science Daily", "The Hill", "Deutsches Ärzteblatt"