death

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!
March 20, 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.

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It's this mystery that I hate. The fact that no one knows what happens after we die. The fact that 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 Geelong-based neurologist 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 moments of consciousness—that last node to shut down before the lights go out.

This is Shaw. He's standing over the cadaver of a woman who donated her body to Deakin University so that medical students could train with real specimens. For my purposes, it seemed logical to start a conversation about death by looking at a dead person. A stretcher was wheeled in, a bag unzipped, and suddenly we were looking at the body of an old woman. Shaw 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 not quite uncomfortable. There was something in the way the embalming fluid had rendered her flesh like poached chicken that made things less weird. I wasn't comfortable with the eyelashes, though. There was something about them that said, "I was pretty, once." They seemed to underline the ubiquity of death. In time, I thought, everyone will look a bit like this.

Formaldehyde was declared carcinogenic in the late 2000s, so modern medical schools now use ethanol solutions as preservatives. As Shaw 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-colored 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 Shaw, 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 on that theory. "Look, I'm skeptical," 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 Shaw 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'd 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 declared dead. Yet despite the results, Dr. Parnia later admitted that the experiences were "probably an illusion… Although If I knew the answers then I don't think I would have engage, and spent 12 years of my life and so much of my medical reputation to try to do this."

Shaw 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, colored 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, colored 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. It's 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 it will be like when I die at 4 AM.

I asked Shaw 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?" Shaw explained that because the brain's blood supply comes from below, the brain tends to die from the top down, claiming our most human characteristics first. Our sense of self, our sense of humor, our ability to think ahead—that stuff all goes within the first ten to 20 seconds. Then, as the wave of blood-starved brain cells spread out, our memories and language centers short out, until we're left with just a core. As Shaw 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 breathe and have a pulse."

I wanted Shaw 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 Shaw I was disappointed, and that I'd hoped science would offer more. That's when Shaw revealed he believes 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 realized it was possible he feared the same things I feared: the unknowableness of existence and the existential pressure of death. I'd come to Shaw for answers; he'd gone to a priest.

"There's a part of me that's always recognized I need my faith, and that life would be difficult without it," Shaw 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."

As I was driving back to town after we said goodbye, I got to thinking. I'm not a religious kind of guy, but I found solace in the idea that Shaw was. That and the fact that 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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