The human brain

[Tero]

Our neurons are actually all fighting for territory, against the other neurons, at all times


Guardian: One of the great mysteries of the brain is the purpose of dreams. And you propose a kind of defensive theory about how the brain responds to darkness.
Eagleman:
One of the big surprises of neuroscience was to understand how rapidly these takeovers can happen. If you blindfold somebody for an hour, you can start to see changes where touch and hearing will start taking over the visual parts of the brain. So what I realised is, because the planet rotates into darkness, the visual system alone is at a disadvantage, which is to say, you can still smell and hear and touch and taste in the dark, but you can’t see any more. I realised this puts the visual system in danger of getting taken over every night. And dreams are the brain’s way of defending that territory. About every 90 minutes a great deal of random activity is smashed into the visual system. And because that’s our visual system, we experience it as a dream, we experience it visually. Evolutionarily, this is our way of defending ourselves against visual system takeover when the planet moves into darkness.

https://www.theguardian.com/science/202 ... lbuquerque

[Tero]

One more:
G:How can we maximise our brain power, and what do you do to switch off?

Eagleman: There’s this myth that we only use 10% of our brain that, of course, is not true. We’re using 100% of our brain all the time. But the way information can be digested and fed to the brain can be very different. I think the next generation is going to be much smarter than we are. I have two small kids, and any time they want to know something, they ask Alexa or Google Home, and they get the answer right in the context of their curiosity. This is a big deal, because the brain is most flexible when it is curious about something and gets the answer. Regarding switching off, I never take any downtime and I don’t want to. I have a very clear sense of time pressure to do the next things. I hope I don’t die young, but I certainly act as though that is a possibility. One always has to be prepared to say goodbye, so I’m just trying to get everything done before that time.

[JimC]

I could understand "neural takeover" happening at a slow rate - if someone becomes blind, then in a few months time, it would not surprise me to see neural networks associated with vision weaker, and other sensory networks stronger. But overnight? His hypothesis reminds me of the compelling ideas that came into my mind when stoned out of my mind, to be revealed as absurd when the high wore off...

[Tero]

Yes, it's quite quick. Kandel worked out the connections happening with long term memory:
https://en.wikipedia.org/wiki/Eric_Kandel

[Brian Peacock]

Some people who are losing their sight experience a kind of residual visual hallucination.

https://en.wikipedia.org/wiki/Visual_re ... ucinations

[Tero]

I could understand "neural takeover" happening at a slow rate - if someone becomes blind, then in a few months time, it would not surprise me to see neural networks associated with vision weaker, and other sensory networks stronger. But overnight? His hypothesis reminds me of the compelling ideas that came into my mind when stoned out of my mind, to be revealed as absurd when the high wore off...

I have the Eagleman book now. People who undergo experiments in sight have been blindfolded for some days. In one day they start using the visual cortex for things to do with touch.

Changes in brain neurons involve new synapses. These are formed fast and also removed fast from disuse.

When the blindfold is removed, the people do not observe much of a change, as the majority of the visual cortex stayed the same.