Itching

[Viking]

It's official -- this article on itching blew my tiny prosimian mind.

The images in our mind are extraordinarily rich. We can tell if something is liquid or solid, heavy or light, dead or alive. But the information we work from is poor—a distorted, two-dimensional transmission with entire spots missing. So the mind fills in most of the picture. You can get a sense of this from brain-anatomy studies. If visual sensations were primarily received rather than constructed by the brain, you’d expect that most of the fibres going to the brain’s primary visual cortex would come from the retina. Instead, scientists have found that only twenty per cent do; eighty per cent come downward from regions of the brain governing functions like memory. Richard Gregory, a prominent British neuropsychologist, estimates that visual perception is more than ninety per cent memory and less than ten per cent sensory nerve signals.

I actually read all of the article, and I must say that it was pretty interesting.

[Beirut]

I actually read half of the artcle and I must say it was pretty interesting.

I remember reading something a few years ago talking about how pain and itching can cancel each other out. A person can have an injury that hurts, but when he gets morphine, the pain stops and the itching can start, but when the pain returns, or if scratching causes pain, the itching subsides in relation to the increase in pain. Something like that.

[Whacker]

I really have a hard time swallowing some of that article, but I guess I must. How the hell do you scratch THROUGH your skull? The skull is one of the thickest, strongest bone structures in a human body.

[Lemur]

Hmm, depends on which part of the skull, doesn't it? Obviously, as any kid who played soccer knows, the front of your skull is tough stuff. The sides? Not in the same league. But even given that, yeah, scratching through your skull would take some doing.

Frankly, I was more interested in the stuff about perception and brain-filtering.

[LittleGrizzly]

Its pretty much along the same lines as an article we had here a while back which states

If the frist and lsat ltteer saty in the smae pcale you can raed the wrod crrectoly

that was actually quite complicated....

[Ironside]

Red the whole article as understanding of how the brain works is pretty interesting, and the broken cases is most telling.

Wouldn't really surprice me if it's correct, it makes sence from what I've red about other things and the more you read about the brain the weirder it gets, take hemineglect for example.
Loosing the concept of left or the concept of your limb (making that limb you carry around being fake, dead or someone else's).
That can make you wake up one day and discover that someone has placed a dead leg in your bed and when you throw it away from the bed, you discover to your horror that someone has stitched the dead leg to your body.

Edit: Another example of the amount of processing seeing things require is when you see a picture but cannot make out what you see until after a while, then it becomes obvious and you can immidiatly see it the next time you see the picture. Point is that you visual center have always seen everything, but understamnding what you see is the demanding part.

[PBI]

I read an interesting article on vision a few years ago which this piece reminded me of; apparently, almost all of the colour receptors in the retina are concentrated directly behind the pupil, in a relatively small area. This means that your peripheral vision is essentially black and white; your brain simply "fills in" the missing colours from memory, or if it can't, it guesses (and quite often gets it wrong).

Edit: Oh, I forgot to mention, that article made me itch like crazy. Thanks a bunch, Lemur.