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Neuron Path Discovery May Change Our Conception of Itching
Hugh Pickens writes "Historically, many scientists have regarded itching as just a less intense version of pain, though decades spent searching for itch-specific nerve cells have been unfruitful. Now, Nature reports that neuroscientist Zhou-Feng Chen and his colleagues at Washington University in St. Louis, Missouri have found the first behavioral evidence that there are separate circuits of nerve cells to convey itchiness and pain, and their studies suggest that itch and pain signals are transmitted along different pathways in the spinal cord. 'Most people accept that there are specific, highly specialized neurons for sensations like taste,' says Chen. 'But for pain and itch this is much more controversial.'" (Continues below.)
"Two years ago, Chen's group discovered that a cell-surface protein called the gastrin-releasing peptide receptor (GRPR) is important for sensing itchiness but not pain in mice. When Chen and his colleagues destroyed GRPR-bearing neurons by means of a cell toxin, the mice reacted to painful stimuli just like normal mice, licking themselves and flinching or jumping in response to heat, highly irritant chemicals and mechanical pressure. But when the researchers injected the animals with chemicals that normally cause scratching, such as histamine, they barely responded, and the greater the number of GRPR-expressing neurons destroyed, the more subdued was the scratching response."
[...] the first behavioral evidence that there are separate circuits of nerve cells to convey itchiness and pain, and their studies suggest that itch and pain signals are transmitted along different pathways in the spinal cord.
This got me thinking...
You know how it is when you're stuck in a conversation at work with Bob the Office Drone and you get a terrible itch building up in waves across your scrotum? The kind that makes you force a smile on your face while you're thinking "Man oh man, I wish Bob would fuck off so I could scratch myself!"
Well... quadriplegics don't get that! Lucky bastards.
Guess I'm a "the glass is 3% full" kind-of-guy.
.
Trolling is a art,
"Mice that had lost the GRPR-producing neurons reacted to painful stimuli just like normal mice, licking themselves and flinching or jumping in response to heat, highly irritant chemicals and mechanical pressure."
Poor mice :(
I propose the name "STD detection neuron pathway". Now hand me that cream and leave me alone.
These posts express my own personal views, not those of my employer
Great. After reading that, now I'm keenly aware of itching sensations all over my body - not unlike watching someone yawn.
I have always thought that Evolution prefers the minimal amounts needed for life (greater complexity is difficult to maintain UNLESS for a reason). As such, it would be easier on life if the same neuron conveys pain and itch. Yet, Evolution chose to do something different.
I wonder what was the stimuli for that?
I prefer the "u" in honour as it seems to be missing these days.
So we know how we could (possibly) get rid of itches, but is there any research showing what purpose itching has?
So how many of you starting getting an itch after reading this article?
Man, I wish I had your ability to tie the obviousness of itching to fucking Obama being evil. Think they'll name the new Godwin award after your ability here.
Remember, every successful FOSS project started with a developer who had an itch to scratch. Clearly we need more itching.
thegodmovie.com - watch it
Saw it in Science News last year. November 22, 2008.
http://www.sciencenews.org/view/feature/id/38338/title/Itch
So what would be the evolutionary reason for itchiness? My theory is that it provided a more acute sensation when something small (like a poisonous insect) was moving across one's skin. Or also perhaps an indicator of infection or disease?
Would this help?
http://www.webmd.com/skin-problems-and-treatments/eczema/news/20090427/bleach-baths-may-help-kids-with-ezcema
Remember - use a _dilute_ solution. And consult a doc about this - maybe your eczema is different.
ok, so why do healing skin wounds itch?
I hope they don't use this to build the Agony Booth found in Star Trek.
This may certainly be interesting from a neuroscience point of view, but I would be troubled if anyone's conception of itching really changed because of a discovery about which neural pathways carry the signal. People who believe in a purely physical world governed by physical laws presumably already accept that everything that happens mentally is in some way or another implemented on our wetware. Is this really drawing some veil back: previously we thought itching was a magical sensation that came directly from fairies, but now we know it's "just neurons"? I would also be cautious about any particularly simplistic reductionist view: most of what goes on in the brain is much more complex than pop-science neuroscience discussions like to make out.
10 PRINT CHR$(205.5+RND(1)); : GOTO 10
After a dentist visit with local anesthesia, I got bitten by a mosquito which caused a terrible itch on my cheek- but I couldn't feel my scratching to relief it. NOT FUN.
Visit http://ringbreak.dnd.utwente.nl/~mrjb/growingbettersoftware to download your free copy of the book
I recall a documentary where a woman had lost her sense of touch, but she still responded to stroking. The explanation was two different systems of nerves. A particularly interesting bit was that the sense of stroking was much slower, as if the signals only travelled around one meter per second. Given the fine line between stroking and tickling, this seems like the same phenomenon as in the article.
Escher was the first MC and Giger invented the HR department.
After a dentist visit with local anesthesia, I got bitten by a mosquito which caused a terrible itch on my cheek- but I couldn't feel my scratching to relief it. NOT FUN.
very interesting, I would mod you up if I could.
I assume that is because pressure sensitive neurons have been knocked out by the anaesthetic.
A nice article and summary. Not entirely new nor inclusive of present theory unfortunately.
Pain is handled by two channels: nocioception, the sensation itself, and the perceptual distress component. This can easily be seen in the actions of the agents affecting each. Sensation is blocked by anesthesia. Interpretation of the pain signal is altered by analgseia -- you may still feel a sensation but you don't care, or at lest you're not so bothered by it. There are different neural pathways and processes to handle these.
It is likely that itching relates to pain in this fashion. The sensation of pressure or stretching of the skin in certain places would be common to all as their are receptors in the skin for these. A parallel pathway governing perceptual interpretation of that sensation, possibly the same one as for pain, would also exist. The resulting interpretation based on personal experience and/or genetically determined wiring would cause different interpretations of the same experience on different individuals, the same individual under different conditions, or (as is common) different locations on the same individual.
"I may be synthetic, but I'm not stupid." -- Bishop 341-B
The car battery is hooked to the monkey's itchy phantom scrotum.
Now. I want to know.
Who screwed the monkey in the first place and got the first case of AIDS?
"No fear. No envy. No meanness." Liam Clancy
the phantom itch
http://www.newyorker.com/reporting/2008/06/30/080630fa_fact_gawande?currentPage=all
same neurological basis as a phantom limb, but far more rare (blessedly so)
it is probably one of the greatest definitions of hell on earth. the itch that never, ever goes away:
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
As someone who's dealt with psoriasis since the age of five I can only hope that they can use this knowledge to find a way to turn the fucking itching OFF. :(
Obviously so did porn. Not sure if "scratch" is the right word there, though ;)
A polar bear is a cartesian bear after a coordinate transform.
When I say a niche, I don't mean an itch like you have when you have an itch. I mean a niche like you have when you have a notch.
Mod parent up. Good link to an utterly fascinating article, though, from the article, it seems to suggest not so much that itch is a function of nerves/nerve endings insofar as itch is a function of the brain. The linked article even makes car analogies. A must read. :)
i have tinnitus
which, really, is "phantom hearing"
i hear a steady tone all day, and its not in my ear, its in my brain. i've grown used to it, accepting the fact i'll have this my whole life, and so it doesn't really bother me that much anymore, i go whole weeks now barely paying it any attention, and your mind just edits it out of daily life
but in the article they talk about the guy with the phantom limb pain... and they do a little trick with him standing perpendicular to mirror, and the brain sees two arms, and... voila, it resets the brain, no more phantom limb pain
amazing! wtf!?
i'm suddenly filled with hope for my tinnitus (false hope?)
if only there were such a neurological sleight of hand like those mirrors in that article, like that, but for the ear instead
i've been thinking about it... a movie of loud noise events without a soundtrack?
i don't know, some way like those mirrors to draw attention to the brain that, in fact, there is no tone playing, you can turn that circuit off now, thank you very much
but tinnitus is not uncommon, so me, or anyone else, who figures out the neurological sleight of hand like those mirrors and the phantom limb pain... to trick the brain into noticing: oh yeah, there is no tone playing, turn that off
the person who does that for tinnitus will win a nobel in medicine and become a millionaire, i promise
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
the problem is that it is equivalent in both ears. but i agree with you that twiddling around that frequency, some sort of volume/ frequency oscillations, might just jigger the neurological circuit into noticing. thanks! ;-)
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
noise cancellation by matching the frequencies and volumes is actually not that wacky, because the tone i hear is very high frequency, very low volume, perfectly constant and a perfect tone. meaning it is simple, not complex. so it wouldn't be difficult to match and cancel out
however, the problem is, like a phantom limb, phantom hearing is deafness... its just that with tinnitus the matching circuitry in the brain is left in the on position rather than the off position
the tiny hairs in my ear at that frequency are dead, they aren't sending any info to the brain. the sound i hear, although perfect and simple and telling me the noise is external, is all in my mind. so even if i matched everything perfectly, there's nothing that would transmit the antioscillation to my brain ;-(
but thanks anyway ;-)
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
god I hope they research this faster! iva had an itchy asshole for the last 10 years and cannot stop scratching, espeically at night when you're half asleep and dont know what your doing. it's not bacteria (taken pills) not 'roids, doctor cannot see any and cream doesnt help.
This would be modded as funny if it werent so depressingly true. maybe it's all the sitting down working at PC terminals for like 12 years.
Just in case you were all interested in my very personal medical problems.