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Comment by snet0 | Hacker News Reader

It's so strange to me that the brain could be so damaged as to lead to facial paralysis and deafness, as well as seizures, but still function well-enough for the person to complete their doctorate.

Did he just get unlucky, and receive a precise zap to the "right side of the face" zone? Or did the brain have to adapt under stress, and decided that this functionality was the sacrifice that had to be made?

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I talked to a biologist once that was running experiments on mice in front of a particle accelerator. He was testing to see how well the mice responded to both routine and unfamiliar tasks after receiving some level of dosage from the high energy particles (heavy ions I think). The mice usually responded to routine tasks as well as they had prior to the exposure but had much more trouble responding to the unfamiliar tasks. The theory was that the particles damaged the elastic parts of the brain more than the plastic parts, that the brain had more trouble forming new connections to solve problems but strong connections formed by training survived the exposure. The experiments were to study how space radiation may affect astronauts solve problems when confronted with less familiar or totally new ones.

Steven Keating is another incredible example of what the human brain is capable of. He was very successful doing research at MIT even did a few TED talks after having nearly half his brain removed. Unfortunately he is no longer with us.

https://news.mit.edu/2019/celebrating-curious-mind-steven-ke...

You can read studies of people who had their corpus callosum severed. This cuts off all communication between left and right hemispheres permanently. They maintain full and normal function, but the left and right halves of their bodies seem to take on independent lives mostly unaware of each other. You can ask a question and the mouth will give one answer but the left hand may write out a completely different answer (vocal language processing is controlled by the left hemisphere, where left arm is controlled by the right hemisphere).

This suggests even just half the brain can maintain the full set of higher cognitive abilities of a normal healthy human, but only half the motor control, which is presumably more dependent on hard-coded IO ports between the brain itself and the nerve buses running to the actual body part being controlled.

Which is to say there is an actual "right side of the face" zone, but there is no zone for higher reasoning in general. Unless you destroy the entire frontal cortex, much smaller subsets of it can fully function as if whole.

I think Daniel Dennett used this evidence to argue that the entire notion of self is an illusion. The brain is so highly redundant that it really consists of countless selves, a distributed system that dynamically comes to consensus but each component is fully capable of operating on its own or as part of a smaller distributed system when the network gets partitioned.

There have also been experiments run on split brain patients that suggest our idea of self is a reactionary rationalisation based on what the rest of our brain is doing.

For example - asking, whispered into one ear, a person to get a drink from a vending machine because I, the experimenter, wanted to take it home with me to drink later. Then when the subject returns, asking, whispered into the other ear, why they got the drink, to which they reply "because I was thirsty"

When I was a child my father was visited by a former colleague, who previously had a stroke. The colleague was partly paralyzed. He had great difficulties talking and to me it looked like he had also problems thinking straight. It appeared that his brain was severly damaged by the stroke. You cannot imagine my surprise when, as he left, he went into his car and drove away just like that.

The brain is very plastic. Which is why often the first sign of a brain tumor (including in people working mentally intensive jobs like PhD student) is a seizure, or paralysis, or deafness. All signs that plasticity in some part of the brain has reached its limit.

i don't follow from this why plasticity reaching its limit in some part of the brain manifests overtly as seizure/paralysis/deafness. those sound more like existing pathways being disrupted, as opposed to the ability to form new pathways being inhibited?

A tumor can get surprisingly big without being noticed because the brain just routes around the damage as the tumor grows. Until it no longer can.

https://news.ycombinator.com/item?id=26344650

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