Edit: But look at what has been done with hearts and kidneys...
Hearts and kidneys are tinker toys! I am talking about the central nervous system!
I am a scientist, not a philosopher! You have more chance of reanimating this scalpel than you have of mending a broken nervous system!
...I am not interested in death! The only thing that concerns me is the preservation of life!
[jams the scalpel into his leg...
:)
* Heads in jars, but, of course the basis of the series is Fry coming out of "cryogenic stasis"
** Caveman lawyer ... the usual mix of stupid / corny but with some amusement value, I guess ... can't even quite remember how dumb vs. funny that one was ...
New neurons cannot be created in an adult brain (only new synapses), so over the years it's a very slow process of brain atrophy where neurons that die for any reason cannot be replaced. That already makes indefinitely untenable in a messy living system, since many of the inportant bits can't regenerate.
And then neurodegenerative diseases are really hard bugs to fix, those are the fast brain atrophies where you get motor problems, amnesia, impaired cognition, dementia, and so forth.
Avoiding stroke and hypoxia is one thing, but keeping the cell and protein machinery running and self-healing forever without any deadly bugs is a tough ask. It's only optimized to reproduce, not to live forever
That isn't strictly true. New neurons do get created in adult humans, in at least two regions of the brain, but probably more. There is even some evidence of cannabis potentially contributing to this process.
That very Wikipedia article says that adult neurogenesis essentially does not exist in humans, according to the latest studies.
This used to be a very controversial topic, and some people still hold on to the older view, but new research has found nothing in the last place where it could have been plausible.
Wayland-Yutani vibes