We Dissected a Brain to Understand What Happens When You Die

We Dissected a Brain to Understand What Happens When You Die

What's happening in the last 30 seconds before death? Let's find out!
20 March 2017, 10:00pm

It's usually just before dawn when I think about death. That 4 AM mystery zone when I wake up and get a bit worried about what it'll be like to die. I imagine it'll be a bit like throwing up. Like I might feel sick for a while, and then I'll feel really sick, and then there will be 30 seconds when I get that feeling like, Right, this is happening. And then darkness will rush in and everything will go quiet and I'll gasp and think, Oh. And then… after that, I can't imagine

It's this mystery that I hate. The fact no one knows what happens after we die. The fact our most consoling answers come from religion and life insurance commercials. And the fact that at some point I have to strap into this weird ride and go wherever it goes, even if that place is nowhere. I hate this, which is why I wanted to find out what, if anything, we do know.

So I met with a Geelong-based neurologist named Dr Cameron Shaw. Together we dissected a human brain and ran through what happens in the final seconds before you die. Then I asked him to show me the final holdout of the consciousness—that last node to shut down, before the lights blink out.

This is Dr Cameron Shaw. He's standing over the body of a woman who donated her body to Deakin University so medical students can train with real specimens. For my purposes it seemed logical to start a conversation about death by looking at a dead person, so a stretcher was wheeled in, a bag unzipped, and suddenly we were looking at the body of an old woman. Cameron removed the paper towel from her face and her mouth was wide open, her eyelashes long. Her hands looked like my nana's.

The feeling was strange, but maybe not uncomfortable. There was something in the way the embalming fluid had rendered her flesh like poached chicken that made things less weird. Although I wasn't comfortable with the eyelashes. There was something about her eyelashes that said, "I was pretty, once." Again this seemed to underline the ubiquity of death. In time, everyone will look a bit like this.

Formaldehyde was declared carcinogenic in the late 2000s, so modern medical schools now use solutions of ethanol as a preservative. And as Cameron peeled the lid off a bucket of ethanol filled with human brains he explained the scientific definition of death. "Basically it's a catastrophic loss of blood flow to the brain," he said, scooping out one cream-coloured specimen. "We know that tunnel vision emerges when there's a disruption of blood supply to the brain. So the first thing you notice when you faint is a narrowing of the vision, followed by blackness." According to Cameron, death would feel similar to fainting, because—barring some sort of cataclysmic injury—both are caused by a lack of oxygenated blood.

His description of narrowing vision sounded a bit like a light at the end of a tunnel, so I asked for his opinion. "Look, I'm sceptical," he said. "I think out of body experiences have been debunked, just because the mechanisms that produce sight and record memories are inoperative." In short, he explained, it's more likely to be an effect that occurs before a loss of consciousness, rather than something that happens during.

I sort of knew Cameron would say this because I'd done some reading a week earlier, and sent him what's still the most famous study on near death experiences (NDEs). Completed by Southampton University's Dr Sam Parnia in 2014, the study examined more than 2,000 people who suffered cardiac arrests at 15 hospitals in Austria, the US, and the UK. Of this number, nearly 40 percent had experienced some sort of "awareness" while they were clinically dead. Yet despite the results, Dr Parnia later admitted "this is probably an illusion… Although If I knew the answers then I don't think I would have engaged and spent 12 years of my life and so much of my medical reputation to try to do this."

Cameron agreed he didn't have a conclusive theory about the results, but confessed reputation is an important reason why neuroscientists spend so little time on NDEs. "I've never met anyone at a medical conference who wants to talk about these experiences," he said. "But I think part of that is the nature of the medical profession. Our job is to prolong life, so talking about death is a bit like talking about our limits."

After this Cameron cleaved a brain in half with a scalpel. He explained living brain tissue is generally softer—"like jelly"—but preserving fluid tends to harden it into something closer to a pickled egg. "It's so soft that even just a collision with the inside of your skull can give you brain damage. Or it'll set off catastrophic swelling that can crush your brain inside the skull."

Once the brain had flopped apart Cameron talked me through its structures (which we've photoshopped for identification). Essentially the human brain has evolved in the same way that someone might add extensions to a house. The theory is that the most primitive core developed first, millions of years ago in some mammalian ancestor, and hasn't changed much since. This is the basal ganglia, coloured pink, which controls both voluntary and involuntary movements as well as raw desires—including hunger and sex drive. As we go out the structures become more "human," which takes us to the Hippocampus and temporal lobe, coloured blue, which are associated with learning and memory.

Finally, the yellow outer layer of the brain is our latest development, and something of a crowning achievement. This is the cerebral cortex, comprised of four lobes, and in charge of everything from social decisions, to our sense of right and wrong, and—that most human trait—our ability to plan for future outcomes. This is the part of my brain that allows me to dwell on what'll be like when I die at 4 AM.

I asked Cameron to take me through the process of death. "Let's assume the blood supply is shut off," I began. "What happens over the next 30 seconds?" Cameron explained that because the brain's blood supply comes from underneath, the brain tends to die from the top down, claiming our most human characteristics first. Our sense of self, our sense of humour, our ability to think ahead—that stuff all goes within the first 10 to 20 seconds. Then, as the wave of blood-starved brain cells spread out, our memories and language centres short out, until we're left with just a core. As Cameron describes, people with only the core are in a vegetative state. "For all intents and purposes you could say they're dead because they don't have a consciousness or an awareness of their surroundings. But if these basal structures are intact they'll still breath and have a pulse."

I wanted Cameron to tell me that as the darkness crept in, it'd be my soul that toughed it out. But nope. As he described it, the soul—or maybe the features we associate with a soul—they all go first, leaving only an ability to breathe and shit until the very last. Maybe that's unsurprising, but it's not what I'd hoped for.

I told Cameron I was disappointed and that I'd hoped science would offer more, to which Cameron admitted a belief in god. "I think I'll always have my scientific thinking and I'll always have my faith and I'll just run them in parallel," he said. With that I realised it was possible he feared the same things I feared: The unknowableness of existence, and the existential pressure of death. I'd come to Cameron for answers, he'd gone to a priest. I told him this and he took a moment to think about it.

"There's a part of me that's always recognised I need my faith, and that life would be difficult without it," he said slowly. "It's a source of comfort when you're seeing—as I am—people who are unwell, and dealing with horrible things through no fault of their own. And science can't explain these random events, so applying meaning to a random world is one way in which I've found my faith useful."

Later, after we said goodbye, as I was driving back to town, I got thinking. I'm not a religious kind of guy, but I found solace in the idea that Cameron was. That and the fact all of us, everywhere around the planet, have these beautifully mass-produced brains, which all fear death and the unknown. Suddenly, assuringly, the line "we all die alone" felt a little less accurate.

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