[karpathy]

This also reminds me of Hemispherectomy[0] where an entire half of the brain is surgically removed in extreme cases to prevent seizures. And amazingly, especially if you do this on younger children:

"Studies have found no significant long-term effects on memory, personality, or humor,[4] and minimal changes in cognitive function overall."

If you don't _really_ need half of the brain and you don't _really_ need the cerebellum, I wonder how little (and what part) of the brain we actually do _really_ need. And then there are so many people living just fine with lesions in so many parts of the brain.

It's just amazing. Imagine going into our code bases and tearing out entire classes or modules; That wouldn't go down well.

[0] http://en.wikipedia.org/wiki/Hemispherectomy

[lostlogin]

>> It's just amazing. Imagine going into our code bases and tearing out entire classes or modules; That wouldn't go down well.<< It's probably more like removing half the CPU cores and your clever code being ok with this.

[Pxtl]

Thinking of the brain as a computing platform is never a good metaphor. Neural networks do not have a rigid delineation between instruction-storage, data-storage, and CPU. Every neuron wears all three hats and intertwingles those concepts.

[LesZedCB]

Von Neumann architecture isn't the only form of computation that exists.

[Pxtl]

Fair enough. I obviously meant a typical desktop/laptop/smartphone/server/whatever.

[lutusp]

True. If it were, what humans do with their biological CPUs would be impossible. Too bad we don't understand our own brains.

[ivanca]

In our defense, they didn't grow to be understood but to serve its purpose. So it's akin to a code base with billions of years in the making, without any good documentation.

[dsuth]

Think you meant 'intertwines'. Thanks for the laugh :D

[knd775]

Actually, it's more like ripping out the GPU and the CPU still being able to handle video decently.

[Dylan16807]

Which is? Hemispherectomy is close to taking out half the cores. Missing cerebellum is close to what you described.

[wwweston]

In fact, it's almost like a typical state-of-the-art computer is a limited (perhaps even poor) metaphor for the brain.

[FUCKUP]

I would imagine that it would be like cutting a hologram in half or what you described.

[outworlder]

Where does the code live, though? :)

[ionforce]

As others have mentioned, I think this is closer to treating them as redundant CPU cores.

Ripping out code would be like... radiation. Mucking with DNA. And that can be really adverse, just like ripping out/changing code.

[inportb]

Radiation would probably be analogous to burning out random transistors, and you could target specific areas if you wanted to.

[wpietri]

If you enjoy thinking about this, you might like the book "Blindsight," a sci-fi novel written by a biologist. The main character had a hemispherectomy as a child, and all the major characters are far from neurotypical. The book is creepy as hell, but incredibly interesting.

[3rd3]

Maybe the redundancy offers an evolutionary advantage?

[CapitalistCartr]

Severe brain injuries are all too common in modern times and were probably more common in prehistoric times. X-rays of (mostly) men with foreign objects through their brain are all too common. I suppose being flexible about which part of the brain does what would make the difference between a survivable and recoverable injury, and a debilitating injury, probably leading to death.

Edit: Steven Pinker, in "The Better Angels of our Nature: Why Violence Has Declined", makes it out to be 15% average death by violence, so, pretty common. Explaining his graphs, he says, “The topmost cluster shows the rate of violent death for skeletons dug out of archaeological sites.” “The death rates range from 0 to 60 percent, with an average of 15 percent.”

[sitkack]

WTF?! Why wouldn't this have the same side effects as a stroke? Blindness, deafness and paralysis?

[Sanddancer]

Age is one of the big issues. The brain's fairly good at routing around problems when you're young and the brain's flexible; it's why young polio patients were able to learn to walk again even after spending months in an iron lung. When you get older, because there's a lot more well-established connections, the brain becomes less capable of adapting to sudden loss of functionality.

[leoc]

The answer to that seems to be "yes, it would": https://en.wikipedia.org/wiki/Paul_Bach-y-Rita#Research_into...

[narag]

I wonder how little (and what part) of the brain we actually do _really_ need.

Maybe we need the software. The cloud provider sometimes has more available instances, other times less of them

[mamcx]

Not that crazy to say "You only use % of your brain!".

So, naive question: Could be correct to think that if half the brain is "enough" to have a full life, then the other half is utilized (in normal brains) but is wasting in doing unnecesary work? ie: Could be the brain is truly under-utilized, under-performing all the time? Like, is lazy?

[tim333]

Brains are probably lazy for the same reason animals in general are lazy - to save energy. The brain accounts for something like 25% of the body's energy use. I'm guessing it's similar to CPUs where most of the time they are under-utilised but can fire up when needed.

[Symmetry]

You're only using a certain percent at a time, but all the different sections of your brain do different things. And they are lazy when they can get away with it, read Thinking, Fast and Slow for some more details but even when you're thinking hard you're not using your whole brain. It's not at all obvious to me that the glucose supply, oxygen supply, or cooling of the brain are sufficient for you to run it at 100% without dying.