The idea of a near-death experience has captured our imagination for centuries, with reports of white light, visits from loved ones, and hearing voices. But are these experiences simply the product of a dying brain or do they reveal something more profound about human consciousness? A new study conducted by researchers at the University of Michigan provides early evidence of a surge of activity correlated with consciousness in the dying brain.
Led by Jimo Borjigin, Ph.D., associate professor in the Department of Molecular & Integrative Physiology and the Department of Neurology, the study is a follow-up to animal studies conducted almost a decade ago in collaboration with George Mashour, M.D., Ph.D., the founding director of the Michigan Center for Consciousness Science. The researchers identified four patients who passed away due to cardiac arrest in the hospital while under EEG monitoring. All four of the patients were comatose and unresponsive. They were ultimately determined to be beyond medical help and, with their families’ permission, removed from life support.
Upon removal of ventilator support, two of the patients showed an increase in heart rate along with a surge of gamma wave activity, considered the fastest brain activity and associated with consciousness. Furthermore, the activity was detected in the so-called hot zone of neural correlates of consciousness in the brain, the junction between the temporal, parietal and occipital lobes in the back of the brain. This area has been correlated with dreaming, visual hallucinations in epilepsy, and altered states of consciousness in other brain studies.
The fact that similar signatures of gamma activation were recorded in the dying brains of both animals and humans upon a loss of oxygen following cardiac arrest raises the question of how vivid experiences can emerge from a dysfunctional brain during the process of dying. “Dr. Borjigin has led an important study that helps shed light on the underlying neurophysiologic mechanisms,” said Mashour.
While the findings are exciting, the authors caution against making any global statements about their implications due to the small sample size. Moreover, it is impossible to know what the patients experienced because they did not survive. “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 Borjigin.
Larger, multi-center studies including EEG-monitored ICU patients who survive cardiac arrest, could provide much-needed data to determine whether or not these bursts in gamma activity are evidence of hidden consciousness even near death.
The idea that consciousness does not completely disappear after the heart stops beating raises profound questions about the nature of human existence and the meaning of life. While we may never fully understand the mysteries of the human mind, this study provides a tantalizing glimpse into the possibility that there is something beyond death.
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