People have reported memories of conversations and incidents that occurred in the room their body was in after they were declared clinically dead.
Near-death experiences have long baffled scientists, doctors, and researchers, as they have struggled to understand how people's brains manage to continue to record and process stimuli around them even after their heart has stopped beating and all brain activity has ceased. There is a reason to believe that the brain could continue to function for a while even after death as brain cells take a while to die.
People who have been resuscitated after being declared clinically dead, have reported memories of conversations and incidents that occurred in the room their body was in even after being pronounced brain dead, with alarming accuracy. This accuracy has long baffled researchers because the ability to form accurate memories should logically be impaired once brain functions shut down. People who are resuscitated should not be able to remember anything from their time dead, but fascinatingly, they do.
The director of critical care and resuscitation research at NYU Langone School of Medicine in New York City, Dr. Sam Parnia, told Live Science that there is anecdotal evidence to prove that people who had near-death experiences continued to register information even after death. He said, "They'll describe watching doctors and nurses working; they'll describe having awareness of full conversations, of visual things that were going on, that would otherwise not be known to them," adding that medical staff present on the scene had verified these accounts with astonishment.
There have been studies on the brain activity of dying animals that have demonstrated that they experience a surge in brain activity a few minutes after death, which is rather intriguing. Parnia suggested that people may continue to experience some level of consciousness even after their heart stops, which may account for their ability to remember details from conversations around their deathbed.
Parnia explained the science behind it. He revealed that the medical definition of death for most physicians is when the heart stops beating, explaining, "Technically speaking, that's how you get the time of death — it's all based on the moment when the heart stops," which causes blood to stop flowing to the brain, leading brain function to cease "almost instantaneously." He added, "You lose all your brain stem reflexes — your gag reflex, your pupil reflex, all that is gone."
Within 2 to 20 seconds of the heart-stopping, the part of the brain responsible for thinking, the cerebral cortex, starts to lose all function and eventually flatlines. An electric monitor would not be able to detect brainwaves at this point. Once this happens, a chain reaction of cellular processes is set into motion, eventually causing brain cells to die, but this occurs for hours after the heart stops.
Parnia said that cardiopulmonary resuscitation (CPR) does get a little blood flowing to the brain, but it can only slow down the death of brain cells, not restart the brain. He explained, "If you manage to restart the heart, which is what CPR attempts to do, you'll gradually start to get the brain functioning again. The longer you're doing CPR, those brain cell death pathways are still happening — they're just happening at a slightly slower rate."
Parnia and his colleagues are conducting an extensive study on what happens to the consciousness after death. He said, "In the same way that a group of researchers might be studying the qualitative nature of the human experience of 'love,' for instance, we're trying to understand the exact features that people experience when they go through death, because we understand that this is going to reflect the universal experience we're all going to have when we die.
"At the same time, we also study the human mind and consciousness in the context of death, to understand whether consciousness becomes annihilated or whether it continues after you've died for some period of time — and how that relates to what's happening inside the brain in real time. What tends to happen is that people who've had these very profound experiences may come back positively transformed — they become more altruistic, more engaged with helping others. They find a new meaning to life having had an encounter with death." Hopefully, the research should shed some more light on the reasons behind near-death experiences.