[ELI5] How do the wrinkles in the brain influence intelligence?


Why smoothness =less intelligent

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More wrinkles = more surface area

We generally correlate the outer brain areas with higher level functions.

The wrinkles also pack the tissue closer together and there has been good evidence to suggest that there is communication over the gaps of those wrinkles, after all the brain is encased in all sorts of liquid and fiber, muscle and whatnot, supplying it with ressources too. so with a more wrinkly brain you got a lot more surface area, stuff is packed closer together and it can possibly communicate more with eachother as it can kinda communicate over those gaps…quite possibly even the neurons neighboring the other side of that gap more directly.. on a smooth brain this just cant happen.

Because the grey matter (part that does the thinking and stuff) is mostly on the surface of the brain. The stuff beneath the surface helps with transferring information to other parts of the brain and other things, but it doesn’t do much processing.

So if you want to increase congnition, you have to increase surface area. And the only way to increase surface area in the same skull is to fold it up, giving it wrinkles.

I’ll try to ELI5 this, but it’s a little complex.

The brain has bits which are of one of two ‘colours’ – white and grey. The white bits are in the ‘middle’, and the ‘grey’ bits are at the surface.

Most of your cognition (what makes you smart) is provided by the grey bits. The more grey bits (so, surface area) you have, the more you have to work with.

The white bits are mostly just myelinated axons – they play a supporting role to the grey ones – they help the grey boyz transfer information where they need it to go, help them out by ensuring they get enough blood and oxygen, etc.

Other people have explained the grey matter part, but the reason why the wrinkles form in the first place is because the skull is only so big. It can only hold so much volume.

So if you want more surface area on something constrained within that volume you need to wrinkle the surface. And that’s what the evolutionary process ended up doing.

You could make the skull bigger, to accomodate a larger smooth brain with a surface area equal to a wrinkled brain. But brains use a lot of energy and need a lot of protection. That would have to be factored in. And then there’s the increased weight of a bigger brain and skull which would mean changes to the neck and musculature. The easiest path is wrinkles.