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 Post Posted: Mon Feb 28, 2022 7:27 am 
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Last week a man died of a heart attack while hooked up to an EEG. The parts of his brain associated with concentration, memory and dreaming all fired up while his heart was failing, and stayed fired up for about half a minute after it stopped beating. To all appearances, his life was flashing before his comatose eyes. An interesting thing to see, but a bit tricky to reproduce on other dying people to see if it's common among humans.

It turns out we don't have to. Back in 2013, 9 dying rats were hooked up to EKGs, and we saw that for half a minute after they 'died' their brains were extremely active; and that the sort of waves we saw are the kind associated with consciousness in humans. Now this opens up the intriguing possibility of testing any other primate besides a human; and if we see the same thing, then we know that it's common in every descendant of the ancestor of all primates and rodents (the odds of it independently evolving in humans and rats after that point not being worth discussing).

But now that we're diving down the cladogram, why stop there? We can finesse an amazing amount of research by running our first test on some farm raised salmon as they're being slaughtered. If we see it there, then we know that all the descendants of the first animal to evolve bones can be expected to have this happen when they die. And if not, we can work our way up the cladogram until we do find the first common ancestor that this occurred in.

Though to me, what would be the most interesting finding (if it actually happens) would be finding this in the brain of hagfish. Our last common ancestor with them is the first animal to evolve a spine. That would mean that every chordate from that time on had that happen to them when they died. Which would be fascinating.

But even if not. Even if the trait only shows up in the common ancestor of the rodents and the primates, it still leaves an intriguing question: what good does it do? How does the behavior of dying brains promote reproductive success? Or is this just an inevitable side effect of something else that is useful? I'm rather curious to see what they work out on that one.

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 Post Posted: Mon Feb 28, 2022 1:24 pm 
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It's a persistent enough legend that is seems likely that this behaviour also turns up in near-death experiences (such as, say, a heart attack but the paramedics get there in time). And then the evolutionary advantage is obvious.

It's like the instinctive part of the brain is telling the thinking, conscious part "Well, we're in trouble and a half now. I haven't the faintest idea of how to get out of this, so I'm just gonna throw memories at you, and maybe you'll spot something useful in there, 'kay?"

If it works - and it only needs to work one in a hundred times - then you pass those last-minute-memory-flash genes down to your descendents. If it doesn't work... then it doesn't, and it makes no appreciable difference.

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 Post Posted: Mon Feb 28, 2022 1:48 pm 
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That would seem to imply that the folks who 'saw the white light' were getting what amounts to '404 error: memories not found'. Either their life was unbelievably boring, or there's some world class memory repression going on here.

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 Post Posted: Tue Mar 01, 2022 1:40 am 
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It's not impossible that they were seeing all the memories at once and they kinda blurred together into a bright light. Or maybe there's multiple things happening at the same time.

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 Post Posted: Tue Mar 01, 2022 2:47 am 
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If we're going to continue along the "searching for an advantage" train of thought, it could also be that the brain doesn't just search through memories but also knowledge and symbolically safe imagery or feelings.

Light is good. It helps us see the danger. While our brain is flailing frantically trying to find something useful it might possibly take the neurons between light and safety and connect those to the ideas of safe harbor offered in a peaceful afterlife or by some higher power. I'm just guessing on that, though. It's an interesting thought.

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 Post Posted: Tue Mar 01, 2022 5:22 am 
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Couldn't resist, so please forgive me:
Terry Pratchett wrote:
It is often said that before you die your life passes before your eyes. It is in fact true. It's called living.

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 Post Posted: Tue Mar 01, 2022 5:38 am 
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Pratchett also mentioned at one point that Rincewind's life had flashed before his eyes so many times that he could skip over the tedious bits.

But yeah, there's all sorts of things that could happen in that near-death environment. It might be different for different people, even (in fact, it very probably is).

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