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Does Your Brain Know When You're Dead? | Unveiled

VOICE OVER: Noah Baum WRITTEN BY: Caitlin Johnson
In this video, we move between life and death... and ask; what role does the brain play in our final moments?

What happens to our bodies when we leave this mortal life? What happens when our time is passed? And how does our brain react and shut down? It's one of the greatest mysteries still facing humankind... but we're getting closer and closer to finding the answers!
Transcript

Does Your Brain Know When You Are Dead?


We’ve yet to achieve immortality so, for the moment, we all gotta die someday. But, even after years of research, there’s still a lot to learn about what happens after we’re gone… or at the moment of passing… if anything happens at all, that is.

This is Unveiled, and today we’re answering the extraordinary question; does your brain know when you’re dead?

Today, we think of brain death as the end of a person’s life. As a state that they cannot recover from. But it’s a relatively recent concept. For centuries before, the heart was generally believed to be the most vital organ. The last frontier for life in the body. And, according to some early theories, the heart was even the location of a person’s soul. But science has since forced us to rethink. We now have technology to keep people breathing even when their lungs have failed, and even when their hearts have stopped beating. It’s also possible for us to restart a heart after losing a heartbeat. So, just because your heart has stopped doesn’t mean you’re definitely dead. Instead, we consider the brain to be the last port of call for life in a person.

There are still huge grey areas where this is concerned, though. And the final criteria for brain death is still subject for much debate in the medical community. People can appear to be braindead for hours, days, weeks, maybe even years if they’re in a comatose state, for example. Often it depends on precisely how brain death is measured… with different laws in different countries requiring either the whole brain to have ceased function, certain parts of the brain, or the brainstem only.

Fortunately, science is always improving… and doctors are getting better and better at determining which coma patients stand the best chance of waking up. Pioneering research led by Ron Kupers of Yale and the University of Copenhagen, for instance, has shown that PET scans (to reveal how much sugar a brain is using) can determine whether somebody is irreversibly brain dead or not. According to Kupers, there’s a lower boundary of usage, below which the chances of waking dramatically fall.

There are also, however, remarkable stories of patients waking up even after extremely long comas. In 1991 a 32-year-old woman named Munira Abdulla went into a coma after a car crash. Then, in 2018, she woke up. Twenty-seven years after the accident. The crash had happened in the UAE, but Munira was treated all over the world and eventually awoke in Germany. Research like Ron Kupers’ and stories like Munira Abdulla’s help us to gain a better understanding of the brain’s role in keeping a person alive. And, sometimes, it can hold onto life for literally years, even when it’s on the brink of death for all that time.

But, so far, we’re considering scenarios where the brain itself is injured or changed in some way. So, what happens when you’re going to die from an injury that doesn’t immediately damage your brain, like a heart attack? In these cases, we know that there’s a delay between the death of the body – i.e., the stopping of the heart – and the death of the brain. With heart attacks specifically, the ultimate killer isn’t your malfunctioning heart… it’s that the brain stops receiving oxygen because of the break in the cardiovascular system. Your brain will eventually die if (for any reason) it’s left without oxygen, which is what happens during cardiac arrest. And, in general, there’s a window of just a few seconds, possibly minutes, between that oxygen flow stopping and the brain shutting down. What actually happens during this window is still shrouded in relative mystery… but there have been experiments aiming to find out.

One grisly study in 2019 involved the brains of slaughtered pigs being pumped with a “blood-like fluid” hours after the pigs had died. And, shockingly, some brain activity was restored by doing this. The animals were long gone, but their brains could still be faintly fired up. Whether this meant the pigs knew that they were brains removed from their bodies… whether this meant that the pigs knew they were dead… it’s not possible to say. And, unsurprisingly, this isn’t an experiment that’s ever been repeated on humans. Though someone can consent to donating their brain to medical science before their death, it’s never usually done with any intention of attempting to essentially resurrect that person. The ethical considerations here are just enormous.

Similar ethical restrictions make it difficult, if not impossible, to obtain a scan of someone’s brain at the moment that they actually die. For as long as a patient is still alive, doctors will do everything they can to try and save them until they either fail or succeed… they can’t simply decide not to treat a fatal injury, and to put the patient in an MRI machine instead just to see what the scan will show.

Studies like this have been done with rats, however. Cruel or not, during a 2013 experiment at the University of Michigan a group of rats were made to have induced heart attacks and their brains were monitored as they died… with results including an apparent increase in hormone release, and general hyperactivity. Meanwhile, a 2011 study - also on rats - reported an increase in serotonin specifically, the happiness hormone. If, then, the same thing happens in humans, our final moments could well be euphoric, or calm, with our fears about death removed as we go beyond.

According to a 2017 study by a team at NYU Langone School of Medicine, the least we might expect is to briefly understand that we have died… After gathering accounts of patients who had suffered cardiac arrest to the point of being pronounced dead, only to be resuscitated shortly afterwards, there were cases when patients could recall the conversations had by doctors and paramedics around their dying bodies. So, the brain knew how close to death it had come, before being brought back.

And perhaps the best indicator for what death holds does come from those who have already been to the edge and returned. Many people say they’ve had near-death experiences, or NDEs. And there are multiple, large studies asking them exactly what happened when they were dead. Often, all the expected tropes and clichés - like the seeing of a bright light or witnessing life flash before your eyes - really are reported. Some will understandably claim confirmation bias here… the idea being that people witness a white light, because that’s what they expect to see in advance. But, on the other hand, could the white light really be a universal hallmark of death? For many, the fact that similar images and experiences are seen and felt so frequently does suggest that death is knowable. That the brain comprehends when we’re going to die, and perhaps creates a familiar encounter in a bid to make sense of it. Away from science, here’s where the idea of an afterlife takes hold.

But there’s still one other widely reported NDE feature… life flashing before your eyes. In many ways, it’s easier to align the seeing of an all-encompassing bright light with the idea of your brain closing off for good. One theory on flashbacks, though, is that they’re the brain falling back to reassuring, day-to-day feelings in a bid to cope with the immense stress of what’s actually happening to you. To comfort you with familiar images and sensations. Another idea is that in those brief moments before death your brain is hurriedly searching for any information that might help you out of this situation. Anything that might save your life. It’s a phenomenon also known as a “life review”.

In a study by the Hadassah University in Jerusalem, published in 2017, hundreds of people who had experienced one were asked detailed questions about their life reviews. Many reported feeling as though time had completely stopped while they re-watched various seemingly random moments from their past. In some cases, the study’s participants weren’t even remembering these moments from their own perspective, but from a disembodied point of view or even from the perspective of somebody else. And often they reported an incredible, transformative effect as all their actions, good and bad, were placed in front of them. An effect which then led them to change their ways and behave more selflessly when they eventually survived their near-death ordeal.

Death is still, and may always be, a part of the human experience that we never completely understand. But, thanks to various theories, studies and experiments, we are getting a better grip on it than ever before. For now, we believe that the brain is life’s last checkpoint. And because, in some cases, there’s a delay between the body shutting down and it shutting down, there may be a small window - perhaps only a few seconds - where it can acknowledge and come to terms with death… whether that’s by welcoming you to a true afterlife or just calming you down enough to embrace the inevitable with warm and open arms.
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