New insights into neural end-of-life

https://neurosciencenews.com/death-brain-neuroscience-25356/

by bookofjoe • 3 years ago

108 17 3 years ago

taejavu• 3 years ago

the brain undergoes a series of changes, including a massive release of glutamate and a surge in gamma and beta waves, potentially linked to near-death experiences.

Speculating: does the above correlate with what we’d expect to see if the brain dumps an amount of endogenous n,n-DMT during death?

dj_mc_merlin• 3 years ago

This is similar to DMT:

https://www.pnas.org/doi/10.1073/pnas.2218949120

Consistent with previous DMT study findings (32, 39), static analyses revealed widespread decreases in alpha power under DMT (P < 0.01, cluster corrected), and increases in both delta (P < 0.05, cluster corrected) and gamma bands (P < 0.01, cluster corrected).

DMT and otherpsychedelics are also influenced by glutamate:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7547711/

Following a double-blind, placebo-controlled, parallel group design, we utilized an ultra-high field multimodal brain imaging approach and demonstrated that psilocybin (0.17 mg/kg) induced region-dependent alterations in glutamate, which predicted distortions in the subjective experience of one’s self (ego dissolution). Whereas higher levels of medial prefrontal cortical glutamate were associated with negatively experienced ego dissolution, lower levels in hippocampal glutamate were associated with positively experienced ego dissolution.

Other forces seem at play as well. When I almost drowned I definitely experienced positive ego dissolution -- you feel at peace with the idea you might die. So it can't be that simple.

huppeldepup• 3 years ago

The "massive release in glutamate" reminds me of some references I read wrt Glutamatergic Storm or Excitotoxicity.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4133642/

https://en.wikipedia.org/wiki/Excitotoxicity

So is the glutamate spike the cause or the effect in this story?

awinter-py• 3 years ago

neural EOL, our high tech internal tooling to Retire a google product

onesphere• 3 years ago

Somatic

ricardo812• 3 years ago

It would be interesting to hear of the evolutionary benefit of this, considering the stage of life it is at.

pgsandstrom• 3 years ago

I would guess it's just like a very complex dam bursting. Nothing intended, just side effects of very complex systems no longer functioning properly.

ricardo812• 3 years ago

Interesting idea. Perhaps another possibility is the brain's one last check to see if the situation is salvageable.

burning_hamster3• 3 years ago

This is correct. For obvious reasons, selection pressures on terminal physiological processes are non-existent (or at least very small). Also, the press release makes it sound as this "wave of death" is something these people discovered or even characterized. It is a well known phenomenon that anybody doing any sort invasive brain imaging observes at some point. As they state in the abstract of the paper:

While the molecular signature of anoxic depolarization (AD) is well documented, ...

The molecular mechanism is also pretty straightforward: dying cells rupture and release ATP. ATP is not only the ultimate energy source but also a potent messenger molecule. In the brain, it excites other neurons, resulting in activation and hence depolarisation of other neurons. Furthermore, in large concentrations, it also induces apoptosis in nearby cells (not just neurons). The result is a chain reaction were the death of some neurons induces death in other neurons, and so on, and this "wave of death" is preceded by a faster moving wave of electrical activation.

DecoPerson• 3 years ago

A1 is a parent of A2, and A2 a parent of A3.

A1 has a genetic trait that makes old age a terribly painful experience, and the moment of death a horrifying ordeal. Far worse than what most experience.

A2 becomes scared of death. As A2 gets older, they behave chaotically because of the trauma from watching A1 die painfully and the fear that they’ll experience the same fate.

A2 does not take good care of A3.

I hope this example (unscientifically) shows that there are likely some strong trends toward genetic traits that support a peaceful end of life period.

I suspect there are also multigenerational trends toward older members dying before they become a drain on a tribe’s resources. An obvious historically-useful benefit, that now leaves us worried sick about our aging parents (that they’ll slip and fall, and activate the “end of life” phase, where they’d have passed away if it weren’t for medical intervention).

2OEH8eoCRo0• 3 years ago

dying before they become a drain on a tribe’s resources.

Why wouldn't evolution select for members who don't become a drain on the tribe? Why age at all?

layer8• 3 years ago

I think it’s likely that the brain’s internal behavior at death doesn’t have a significant evolutionary effect, and instead is just a side-effect of how the brain works in general, which in turn is of evolutionary importance, of course.

krzat• 3 years ago

Is there any purpose to brainwaves, or are they just a side effect of communication between neurons through axons?

Schiphol• 3 years ago

Nobody knows for sure, but there's lots of work on neural mechanisms purportedly mediated by synchronous oscillations. For example, look up the "communication through coherence" hypothesis by Pascal Fries; or Grossberg's "adaptive resonance theory".

New insights into neural end-of-life

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