Maybe our most essential existential drive is to understand the meaning of our own existence. Or maybe it is a deeply rooted, genetically programmed reflex, keeping our mind "busy" as clearly the most distressing event of our entire life unfolds. Maybe it is a last resort, defense mechanism of the body trying to overcome imminent death. Maybe it is a completely artificial effect associated with the sudden surge of neural activity as the brain begins to shut down. I have come across a number of theories trying to explain why life would be flashing before someone's eyes as the brain prepares to die. Some studies have also shown that this brain shutdown is accompanied by a release of serotonin, a chemical associated with arousal and feelings of happiness.īut what about us? If humans can be resuscitated after six, seven, eight or even ten minutes in extreme cases, it could theoretically be hours before their brain shuts down completely. ![]() And after 40 seconds, the great majority of neural activity has disappeared. In rats, experiments have established that after a few seconds, consciousness is lost. What's more, the study did not answer my basic question: how long does it take after the cessation of oxygen supply to the brain for the essential neural activity to disappear? The study only reported on brain activity recorded over a period of about 15 minutes, including a few minutes after death. However, such coupling is not uncommon in the healthy brain-and does not necessarily mean that life is flashing before our eyes. "Given that cross-coupling between alpha and gamma activity is involved in cognitive processes and memory recall in healthy subjects, it is intriguing to speculate that such activity could support a last 'recall of life' that may take place in the near-death state," they write. The researchers discovered that some brain waves, called alpha and gamma, changed pattern even after blood had stopped flowing to the brain. While this was the first publication of such data collected during the transition from life to death, the paper is highly speculative when it comes to possible "experiences of the mind" that accompany the transition to death. But a recent paper examined electrical brain activity in an 87-year-old man who had suffered a head injury in a fall, as he passed away following a series of epileptic seizures and cardiac arrest. It isn't easy to get permissions to study what actually goes on in the brain during our last moments of life. On the contrary, someone who has a protracted history of a serious illness might be more likely to get a rough ride. Some people, having undergone anesthesia while in good shape or having been involved in a sudden accident leading to instant loss of consciousness have little ground to experience deep anxiety as their brain commences to shut down. Could there be anything of my beloved brother's mind left to hear my voice and generate thoughts, five hours after he had passed away? ![]() Then, deterioration reaches a point of no return and core consciousness-our ability to feel that we are here and now, and to recognize that thoughts we have are own own-is lost. Yet, in the last moment I was given to spend with his lifeless body in a hospital room, I felt the urge to speak to him.Īnd I did, despite 25 years of studying the human brain and knowing perfectly well that about six minutes after the heart stops, and the blood supply to the brain is interrupted, the brain essentially dies. No matter how much I refused to believe it on that day, and during the several months that followed, my brother's extraordinarily bright and creative mind had gone, vaporized, only to remain palpable in the artworks he left behind. Only he was not breathing anymore and he was cold to the touch. An hour later, I found him perfectly still and beautiful, his head slightly turned to the side as if he was in a deep state of sleep. ![]() But when I landed, I was told my brother had passed away four hours ago. I set off to Marseille, France, having been summoned to Avignon by my mother because my brother was in a critical state, a few days after being suddenly diagnosed with terminal lung cancer. On June 14, 2021, I was violently reminded of these questions. ![]() Words I remember to this day were the last of Georges Danton on April 5, 1794, who allegedly said to his executioner: "Show my head to the people, it is worth seeing." Years later, having become a cognitive neuroscientist, I started wondering to what extent a brain suddenly separated from the body could still perceive its environment and perhaps think.ĭanton wanted his head to be shown, but could he see or hear the people? Was he conscious, even for a brief moment? How did his brain shut down?
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