Rat had 'no brain' and somehow lived a normal life
news.northeastern.edu
news.northeastern.edu
same case but in humans, he had a "normal" life.
and in 2015: https://news.ycombinator.com/item?id=10810454
Gwerns very detailed write up on the conditoon
Main takeaway (misleading title) is that this rat had a brain, but a region of fluid developed and pushed the brain towards the edges of the cranial cavity. The rat was still able to do most of the other basic tasks as the other rats, but may have suffered from anxiety.
And that's the extent of this article. I don't think we know how higher order functions were affected. I would guess that these (like what humans have) are not necessary to sustain life. A species can exist indefinitely as long as they can feed and reproduce faster than they die. These things are easy to do without higher order functions if food and reproductive mates are readily available.
I wouldn't be surprised if a lab rat without 99% of their brain didn't change much or could still complete basic tasks. I would be surprised if a human without 99% of their brain could function normally in society today, which requires relatively heavy higher order brain function.
> A man with an unusually tiny brain manages to live an entirely normal life despite his condition, which was caused by a fluid build-up in his skull.
> Scans of the 44-year-old man’s brain showed that a huge fluid-filled chamber called a ventricle took up most of the room in his skull, leaving little more than a thin sheet of actual brain tissue (see image of the patient’s brain, above left).
https://www.newscientist.com/article/dn12301-man-with-tiny-b...
It makes sense. I don't know how Game AI Enemies are scripted but they seem to use very minimal code.
This should also imply that the spinal cord is more important, as the brain is just 1/10ths ? of the nervous system.
The classic summary of these studies is by Whishaw (1990), and there's a copy of it (and similar stuff on humans) in this thread: https://twitter.com/markdhumphries/status/107105276276554137...
I once met a patient who was missing literally half of their brain due to an epilepsy resection + meningitis. We had a perfectly normal conversation and, had I not seen the MRI, I never would have guessed.
Visual areas in the left hemisphere represent the righthand size of visual space, while those in the right hemisphere represent the the left part of the world. With one hemisphere totally removed, you'd think the patient would be half blind. However, Dan Guitton's lab showed that D.R. still has some residual "blindsight" and that stimuli flashed in the blind hemifield affect eye movements.
I'm not sure what else, though the patient had a rather normal life: held down a job, was involved in some civic organizations, stuff like that.
Gwern has a good summary, including criticisms: https://www.gwern.net/Hydrocephalus
Shelly and his father Rob Wall spoke of how their six-year-old son has since gained function in 80 percent of his brain. [1]
[1] https://www.newsweek.com/miracle-boy-born-no-brain-grows-bac...
Flippancy aside, rats are sophisticated mammals with basically the same set of higher order functions as ourselves, although of course in different quantities.
But that said, wikipedia suggests that he began recovering his social skills in the years after his injury. Perhaps if he hadn't died young, he could have returned to some sort of normalcy.