Itching

For a long time I’ve thought that itching was due to your body calibrating something. It’s calibrating and testing and it just basically says “hey, can you scratch down here so I can see what this feels like”.

Welcome to the SDMB, amulekii.

A link to the column you’re commenting on is appreciated. Providing one can be as simple as pasting the URL into your post, being sure to leave a blank space on either side of it. I presume this is the one you’re commenting on: http://www.straightdope.com/columns/read/82/why-do-we-twitch-while-falling-asleep

I vaguely remember reading somewhere that an itch is a very primitive form of pain. Maybe a semi-pain.

I remember reading, a long time ago, that the sleep-twitching talked about in the same article is closely related to an epileptic seizure.
Peace,
mangeorge

Is there any correlation between these itch points and acupuncture points?

I don’t have much to offer on the distinctions between itching and pain, but a semi-related anecdote: Today, I had dental work. For roughly 3 hours afterward, my lower jaw / lip / chin were NUMB.

Then the chin started to itch. One of those itches where it feels like it’s inside the flesh.

I tried to scratch.

I couldn’t feel the scratching. I could feel pressure… but scratching / rubbing had NO effect whatsoever. Even pressing fairly deep with the nails didn’t have an effect. I had to be careful not to accidentally gouge myself in the fruitless attempt to stop the damned itching!!!

I suppose I could have poured hot water on my face to try to break the itch pattern, which sometimes helps with bug bites on my legs, but somehow I didn’t see that working out too well.

Anyway - the itching happened even when the pain receptors were completely blocked. It wasn’t terribly pleasant.

Wikipedia suggests that this is not the case, if I’m reading it correctly - there are similar pathways but not identical. My experience today where I felt itching, but was not able to feel pain, would seem to bear that out.

Adding a question about itching below the original question seems completely irrelevant to me, so for those twitchers:

is a much better answer.

While I’m here, in relation to itching, I might point out that pain is very subjective. Nevertheless, the nervous system only ever evolved for 2 reasons:

  1. To detect and run away from harmful things (pain)
  2. To detect and run towards good things (pleasure)

I don’t know about you, but I don’t go looking for mosquito bites or jumping into poison ivy everytime I see it. The average random itch isn’t as bad, but I don’t particularly like them either.

That’s too simplistic to be accurate. Sure, the original sensing mechanism has strong evolutionary advantage by alerting to pain, and thus things to avoid. And that’s the thing. Poison ivy causes a severely unpleasant reaction. Ergo, you avoid poison ivy. Therefore, your senses are doing exactly what they are supposed to. They are also doing exactly what poison ivy wants you to, leave it alone.

Of course getting a hazmat suit and then exterminating all poison ivy is probably not the reaction it desires.

Why is everybody so stuck on the itching thing?
Come to think, I’m surprised Cecil combined the two totally unrelated queries. Getting old, I guess.
mangeorge

First of all, it’s from 1981. So he wasn’t “getting old.”

Second of all, you yourself talked about the itching. :stuck_out_tongue:

Some people get old earlier in life than others. Early onset senility?
Sure I did. And I also talked about twiching. I’m getting old. Too. :stuck_out_tongue:

Scientists find why scratching relieves an itch.

I thought it was because scratching overloads the itch sensors.
Guess I should go read the whole article. :rolleyes:

Longer article fromNYT.

Looks like they still haven’t figured itching out, they’ve just got more information.