American researchers have observed bursts of brain activity in dying patients. This would mean that one could, just before dying, hear or feel external sensations.
THE accounts of near death experiences (EMI) already provided the beginning of an explanation. But studies conducted by scientists from the University of Michigan in the United States, the results of which were published in Ia scientific journal Proceedings of the National Academy of Sciences (PNAS) on May 1, 2023, went further. They studied in great detail (and for the first time in humans) the biological mechanism of the brain just before dying in patients in a coma following cardiac arrest but kept on ventilator support. Through the analysis of electrocardiogram and electroencephalogram (EEG) signals from 4 people before and after the disconnection of the respiratory assistance, the researchers were able to observe several unexpected mechanisms in two of the people (a 24-year-old woman and a 77-year-old woman) just before she died:
► An acceleration of the heart rate.
► Bursts of functional connectivityin other words, the brain activity showed a peak of gamma waves, at a frequency level corresponding to A state of conscience.
► The most stimulated part of the brain was the temporo-parieto-occipital junction (or the temporo-parietal junction, see on the diagram below), an area located at the junction between the temporal lobe, the parietal lobe and the occipital lobe, i.e. above and behind each ear, which is normally associated with awakening or memorizing dreams. It would mean “that the patient sees something, can hear something, and can potentially feel sensations outside of their body“, interprets Jimo Borjigin, lead author of the study. A similar phenomenon has also been observed on a healthy brain during wakefulness and dreaming in patients who have had visual hallucinations and out-of-body experiences ( EMI), can we read in the study.
Thanks to these analyses, the researchers were able to highlight the fact thata “dying” brain is still able to be active. Patients might possess a secret consciousness during the dying process. They also suggest the need for reevaluate the role of the brain in cardiac arrest. Of course, the mechanisms and physiological significance of these discoveries remain to be fully explored, especially since the study was conducted on a very small sample of people, the researchers point out.
Source : Surge of neurophysiological coupling and connectivity of gamma oscillations in the dying human brain, PNAS, May 1, 2023