Reports of near-death experiences have long intrigued and captivated us with tales of white light, encounters with departed loved ones, and hearing mysterious voices. These common elements in near-death accounts raise the question of whether there is a deeper reality underlying these experiences. A new study published in the Proceedings of the National Academy of Science provides early evidence suggesting that consciousness may persist in the dying brain.
Led by Jimo Borjigin, Ph.D., an associate professor in the Department of Molecular & Integrative Physiology and the Department of Neurology, the research is a follow-up to animal studies conducted nearly a decade ago in collaboration with George Mashour, M.D., Ph.D., the founding director of the Michigan Center for Consciousness Science.
The study revealed similar gamma activation signatures in the dying brains of both animals and humans experiencing a loss of oxygen following cardiac arrest.
The paradox of how vivid experiences can emerge from a brain in a dysfunctional state during the dying process is a complex neuroscientific mystery. “Dr. Borjigin has led an important study that helps shed light on the underlying neurophysiologic mechanisms,” commented Mashour.
The researchers identified four patients who passed away due to cardiac arrest in the hospital while under EEG monitoring. All four patients were comatose and unresponsive and, with their families’ consent, were removed from life support as they were deemed beyond medical help.
During the removal of ventilator support, two of the patients exhibited an increase in heart rate along with a surge of gamma wave activity. Gamma waves are associated with consciousness and considered the fastest brain activity.
Interestingly, this increased gamma wave activity was detected in a specific region known as the “hot zone” of neural correlates of consciousness in the brain. This area, located at the junction of the temporal, parietal, and occipital lobes in the back of the brain, has been linked to phenomena such as dreaming, visual hallucinations in epilepsy, and altered states of consciousness in other studies.
The two patients who showed increased gamma activity had a history of seizures, but no seizures were recorded during the hour leading up to their deaths. On the other hand, the remaining two patients did not display the same heart rate increase or heightened brain activity after being taken off life support.
Given the small sample size, the researchers exercise caution in making broad interpretations of the findings. Additionally, the study was unable to ascertain the experiences of the patients since they did not survive.
Dr. Nusha Mihaylova, a clinical associate professor in the Department of Neurology, who has collaborated with Dr. Borjigin since 2015, collected EEG data from deceased patients under ICU care.
“We are unable to make correlations of the observed neural signatures of consciousness with a corresponding experience in the same patients in this study. However, the observed findings are definitely exciting and provide a new framework for our understanding of covert consciousness in the dying humans,” said Dr. Mihaylova.
To gain more comprehensive insights, larger multi-center studies involving EEG-monitored ICU patients who survive cardiac arrest will be crucial in determining whether these bursts of gamma activity serve as evidence of concealed consciousness even in the face of death.
The research paper also includes contributions from Gang Xu, Duan Li, Fangyun Tian, Peter M. Farrehi, Jack M. Parent, and Michael Wang.
Story Source:
Materials provided by Michigan Medicine – University of Michigan. Original written by Kelly Malcom. Note: Content may be edited for style and length.
Journal Reference:
- Gang Xu, Temenuzhka Mihaylova, Duan Li, Fangyun Tian, Peter M. Farrehi, Jack M. Parent, George A. Mashour, Michael M. Wang, Jimo Borjigin. Surge of neurophysiological coupling and connectivity of gamma oscillations in the dying human brain. Proceedings of the National Academy of Sciences, 2023; 120 (19) DOI: 10.1073/pnas.2216268120