I realized that I never know the moment I fall asleep and scientists have debated about the brain retaining function shortly after death or something to that effect.Well I was thinking that what if thats our mind processing or accepting death.This would be my explanation of the light at the end of the tunnel or life flashing before your eyes. It would be like drifting into a dream.I imagine death by brain damage would be something like being knocked out.Have scientists done any studies or reports with something similar to this? Is there any info someone can give me as to why I would this would be incorrect?

I always saw the brain as the first to come and the last to go.

The current medical definition of death is that death occurs when all brain activity has ceased, in both cognitive and autonomous parts of the brain. So your brain could never process your death because the very fact that it is dead stops it from doing so. Your brain can process impending death, but that death can possibly be prevented so its not the real deal.

When you are alive, your brain functions. (Althoughl in some folks, the level of intelligence at which it does is debateable)
When you are dead, it does not function.
Even if you do not remember dreaming, or dream at all, processes both conscious and unconscious are going on as you sleep. If you were dead, they would not.
I don't think it has anything to do with death, I would hazard a guess that rest cycles coordinate with lack of dreaming. It's been documented that people who dream excessively don't get the rest that they need.

On the topic of brains and death. What is it about old age that makes the body just shut down and die? I mean, I know the mody declines even as we are young, but still, what degrades so critically to the point of causing death of the body?

You don't actually die of "old age". Parts simply deteriorate and eventually one gives out. It might be the heart, you might suffer a stroke etc and simply not recover because all the parts are so deteriorated that you can't recuperate.

It makes me think of a cpacitor discharging after youve turned somethign off.
takes time for those electrical impulses to dissipate.

Cells. They age too. After reproducing themselves 50 times (I think) they can no longer clone themselves.

I've always wondered this to, I actually just had a huge conversation the other day with one of my friends about this. I can't really go into it because of religion though

So in a way, it's the same as crop burning? Keep recycling until there's nothing left?

Its actually a built in fail-safe to decrease the probability of malicious mutations (cancer).

The light at the end of the tunnel/ life flashes before your eyes is actually a hallucination, which is very common right before death as a naturally produced psychedelic chemical known as Dimethyltryptamine is released in your brain. Same thing that causes us to dream.