That Neuroscience Guy - Season 7 Finale - The Neuroscience of Death

Episode Date: April 22, 2024

What happens to your brain when you die? Perhaps the more important question is why might your brain cause death? In today's episode of That Neuroscience Guy, we discuss how your brain deteriorates over time eventually causing death, and how your brain might process the moment of your death. 

Hi, my name is Olof Kergolsen, and I'm a neuroscientist at the University of Victoria. And in my spare time, I'm that neuroscience guy. Welcome to the podcast. Now, I just want to say up front that I have a cold. I've been battling it. I came back from Germany last week and I picked something up on the flight or somewhere. So my voice is a bit off and I might cough once or twice. But the reason I bring this up and the reason I didn't wait is that Matt is going on holidays on Thursday, taking a much deserved break for a couple of weeks.

And I'm going to New Zealand to visit some family. So this will be our last episode of this season, and we will be back at the start of June for more episodes of That Neuroscience Guy. So we're going to be gone for just over five weeks, but keep your eyes out. Who knows, we might sneak something out in the middle of that time, but we are planning on taking a bit of a break, and then we're going to keep going. But we are planning on taking a bit of a break, and then we're going to keep going. So, without further ado, today I'm going to talk about a fairly morbid topic. The neuroscience of death.

Now, I'm going to start by talking about death in general, and then I'm going to get more into the neuroscience part of it. Now, one of the interesting things about death is that very few people die of old age. All right. It's, it's just not something that happens. And what I mean by that is that most people die for other reasons before their body would have stopped due to just simply old age. So the number one leading cause of death is heart and circulatory disorders, followed by cancer, followed by respiratory disorders, followed by nervous system disorders, followed by digestive disorders, suicide, transport accidents, mental health disorders, undetermined events, murder, medical complications, pregnancy and birth, war, and terrorism. And we haven't even gotten to the point where you would die of old age, just purely old age. So most people die before they reach the end of life due to natural,

purely natural causes. So what happens as we age? We've talked a bit about aging, so I don't want to spend too much on this. But basically, as we age, your body can't maintain homeostasis, you have a decreased ability to adapt to internal and external stresses. And you have damage to body systems. And this is what happens in the brain. If you want to focus this on the neuroscience of death, from the time we're about 19 to 20, we're losing about 20 to 25,000 neurons a day. And that's assuming you're leading a healthy, normal lifestyle.

So your brain is effectively dying from the time you're 20 or to 25. So even if we could extend the human lifespan for the physiological aspect of things, we would have to figure out how to stop those neurons in the brain from dying. And they're basically not replaced. All right. So your brain is slowly deteriorating. And this is why when we get to the later stages of life, we start to have mental issues. All right. Our memory suffers, our decision-making is impaired, our learning systems suffer. And that's because we're literally, our brains are not what they used to be. Those neurons are dying. Now we're going to get to why those neurons die in a couple of minutes, but that's why your brain starts to fall apart as

we get older, and eventually it would lead to death. Now, one of the principal reasons that we die is we have lost our ability to maintain homeostasis. So we can't keep our body systems balanced. So older people are more susceptible to cold and heat for this very reason. They're more susceptible to any number of things because of this loss of ability to maintain homeostasis. All right. And this impacts blood sugar levels, water content, pH levels, body heat, and nutrient levels. So all of these things are impacted as the body ages and the brain. It impacts neural function. The stuff, all of these things are needed in the brain for normal brain function. So if you start messing around with these things, or

messing around is kind of the wrong phrase, you start losing these things because you're getting older. Well, guess what? This is what's going to lead to your brain deteriorating. Now, our bodies also have a decreased ability to adapt to internal and external stress right so basically the stresses that we put on our body by moving about the world interacting with things our body just can't deal with them the way we are when we are younger you know if we go for a very long walk when we're young or or go for a long run even, you should be able to sleep and recover, right? And then you're fine for the next day. But as we get older, that's harder and harder to do. So these external stresses and these internal stresses basically wear our bodies out.

And that leads to the third and primary reason that death comes about and problems with the brain is you have damage to body systems. All right. So you have muscle deterioration and damage. All right. Our muscles don't function the same way as they used to. You have damage to the skeletal system. You have damage to internal organs and you have damage to the nervous system. Let's just use concussion as an example here. Every time you get concussed, you are basically experiencing a level of brain damage. And that damage isn't always repairable. In fact, very few people come back from a concussion to exactly where they were before. Now, it might look that way on the outside, but the reality is your brain has taken a little bit of damage and that accumulates over time. And of course, we know

examples from professional sports in North America where this leads to CTE by the later stages of life. There's all of this accumulation of brain damage and eventually you cannot, you know, your brain is damaged. It's that simple. Things aren't going to work the same way if the tissue is dead or damaged. So why do we age? You know, what's going on? And there's sort of two main theories about why we age. There's error theories and there's programmed theories. Error theories are kind of what I've been talking about. The wear and tear theory, right? Your body just basically gets beat up by life itself. All right. And that leads to you

eventually dying. And rate of living. So the more you push your body, all right, the more damage that can do. There's something called cross-linking theories, and it's basically proteins damaging organs in the body is what that boils down to. There's free radical theories, which are basically atoms with unpaired electrons, and they just do damage to what they encounter in the body. So all these things inside are creating error. They're breaking things. And this is true in the brain as well. So it's happening within your body, but it's also happening within the brain. And there's DNA damage theories where the DNA itself gets damaged. What's potentially a little bit more interesting, because the error

theory makes sense, right? You know, your body basically gets beat up and it can't recover back to where it was. And eventually at some point this leads to death. But there's programmed theories. So some people argue that it's actually in our genetic code. It's called programmed longevity. We're actually hardwired in our genes to die at a certain point in life. Why? That's the million dollar question, but no one really knows.

There's the endocrine theory that your endocrine system is programmed to basically stop functioning the way it's supposed to. At some point, it has a lifespan. So our hormones basically lead to death. All right. Our hormones don't function the way they're supposed to. And then there's the immunological theory. Basically, our immune system is programmed to shut down. So in all three of these cases, the belief is that our brains and our bodies are programmed to die. From the moment we're born, somewhere in there, there is an expiry date. Now, the reality is scientists don't really know why we age. They have these theories. The error theories make a lot of sense. Now, the reality is scientists don't really know why we age. All right. They have these theories.

The error theories make a lot of sense. All right. Especially if you think of brain damage and the accumulation of problems in the brain. But also, these program theories are interesting as well. And there is evidence for them as well. Now, before I wrap things up, some people ask me, you know, what's going on in the brain when you die, right? Like what happens? Like, does your brain continue living after the body dies? And the cool thing is, is there's research out there that shows this. So when I was doing the research for this episode, I came across a study I'd never read before, and it was fascinating.

So basically, we know when there's a lot of anecdotal evidence that if someone comes back from a near-death experience, they say that they've seen things and experienced things. because we don't know if that stuff happened right before they died, right after they came back, or whether it was truly happening when they were dead. But there's research that suggests it could have happened when they were dead. So check this out. I found this fascinating. A group of researchers basically got permission to monitor people that were about to die. So they were on ventilators and the decision was made to turn off the ventilator and they weren't expected to continue.

So what they did is they started recording EEG data, brainwave data, right before the ventilator turned off, all right, or was turned off more correctly. And what they found was that there was a surge of gamma waves in the brain. So these are oscillations between 31 and 100 hertz or so. And these gamma waves picked up for about a minute to 30 seconds because they tested multiple people prior to death. So it's like the brain knew. Now, this is when prior to the ventilator turning off, but prior to the actual moment of death, though, the doctor turns off the ventilator and the person lives for some period of time.

In the minute to 30 seconds prior to death, there's this increase in gamma oscillations. So it's like the brain knows that death is coming. It is reading the body organs. It's reading the information. It says, yep, this is the end. We're going to shut down. I'll talk about what gamma oscillations mean after very quickly. But what's really crazy is that surge of gamma activity actually continued for a very brief period of time after the person died. Now, just a couple of seconds, but the brain was still active after death. These gamma oscillations were enhanced. All right. So these gamma oscillations pick up right before you die, and they continue for a very brief period of time after you're actually dead. And we're talking

the body is dead. Now, what are gamma oscillations? They're still being studied, but they've been tied to memory, cognition, and attention. So they're also sort of seen as a sign of consciousness. So it's kind of cool that, you know, right before you die and right before, you know, right after you've died, you have this, you know, you have this increase in activity that's associated with memory, cognition, and attention. Now, does this mean your life is flashing in front of your eyes? No, there's no way to determine that. But the brain does have this really cool thing around about the time of brain death, right? The increase in gamma oscillations before that continue for a few seconds after death. All right, that's the neuroscience of death, and that's the end of this season. Like I said, Matt and I are taking a couple weeks away,

but we're going to be back in late May, early June. We may try to push something out in the middle just to keep things going, but we might not be able to. We're going to be in different parts of the world for most of that time. As ever, for the next season that's starting, we want to know what you want to know about the neuroscience of daily life. We're going to spend part of this five weeks going through all the emails, thatneuroscienceguy at gmail.com, all of the messages on X and threads. At that neuroscience guy, send DM me, feel free to, I don't mind. Tell me what, and Matt, what you want to know about the neuroscience of daily life. Of course, check out the website, that neuroscience guy.com links to our Etsy store and Patreon.

Thank you so much to the people supporting us on Patreon. By the way, we haven't sold a lot of shirts. The design is, is what it is. I like it, but I don't know if it's trendy enough. But we have people supporting us on Patreon. If you're not familiar with Patreon, you basically sign up, you find the podcast, and you can send a couple of dollars a week or a month. And all that money goes to supporting graduate students in my lab doing neuroscience research. And of course, the podcast itself. Thank you so much for listening.

We're closing in on 800,000 downloads, which blows my mind. So if you haven't already, please subscribe. All right. My name is Olaf Kregolsen, and I'm that neuroscience guy. I'll see you soon for another full episode of the podcast. And sorry for having a cold today. I promise it'll be gone when we come back at the beginning of June. Thanks for listening.