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Researchers Identify Phantom Limb Brain Activity 165

mmmscience writes "Researchers in Switzerland think they had identified the regions of the brain responsible for creating phantom limbs and the senses that go along with them. Scientists studied a stroke victim who claimed that the phantom limb of her now-paralyzed left arm could do a number of things a normal limb could do, including 'scratch an itch on her head, with an actual sense of relief.'"
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Researchers Identify Phantom Limb Brain Activity

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  • Yes but... (Score:3, Funny)

    by Anonymous Coward on Sunday March 29, 2009 @02:42PM (#27380765)
    What explains phantom brain slashdot moderation?
  • by Anonymous Coward on Sunday March 29, 2009 @02:42PM (#27380773)

    Can you masturbate with a phantom limb?

    • by Hangingcurve ( 1132587 ) on Sunday March 29, 2009 @02:57PM (#27380901)

      If you use the left part of your brain, it feels like someone else is doing it.

    • by Fumus ( 1258966 ) on Sunday March 29, 2009 @02:57PM (#27380903)
      "Look! No hands!"
    • by Anonymous Coward on Sunday March 29, 2009 @03:11PM (#27381019)

      Anything that you have physically experienced once can be replicated with enough focus and mental dedication.

      For lay people, the number of times they engaged in the activity with the now absent limb should impact the ability to recreate the sensations assuming they use an entry-level, single-instance recursion method for manifestation. This method would involve identifying one remembered masturbatory experience, and then recursing on the memory - initially focusing on one aspect of sense memory (ie: olfactory, visual, etc..), and adding sense detail with each iteration.

      It should be noted that persons not already suffering from socialization issues should avoid cultivating the ability to completely self-satisfy, as this can lead to all sorts of socialization issues.

    • by Smivs ( 1197859 )

      Can you masturbate with a phantom limb?

      Yes, and you can type stupid replies with them, as well!

    • Can you masturbate with a phantom limb?

      Dunno, but apparently some girls [] can do some pretty interesting things with one.

    • Only if you have a phantom cock. And the orgasm will be ..err... ghostly
  • Like Gil "The Arm" (Score:5, Interesting)

    by CRCulver ( 715279 ) <> on Sunday March 29, 2009 @02:43PM (#27380787) Homepage
    In Larry Niven's Gil "The Arm" Hamilton stories (collected in Flatlander [] ), the protagonist lost his arm in an accident, but found that without the physical arm he had developed telekinesis with the remaining phantom hand feeling. This persisted after he got a new arm transplanted, so he had in effect three arms. Now, one can discount Niven's interest in the paranormal, peculiar for a writer usually lauded for the believable science of his stories. But I'd be interested to know if in reality the feeling of a phantom limb would persist even after a new prosthetic or even human transplant were added.
    • by mikelieman ( 35628 ) on Sunday March 29, 2009 @02:49PM (#27380833) Homepage

      Or like -- The Phantom Limb!

      "He wears a lot of purple for a white guy. ..."

      • Re: (Score:3, Funny)

        Go Team Venture!

      • "That chode she's with? That's Phantom Limb. In college he was a scrawny little wuss. In a desperate attempt to be cooler than guys like me, he had his 12 year old roommate create a machine that speeds up the muscle building process. The machine worked so well that every molecule in his extremities was accelerated beyond the speed of light. There were two side effects. One! He could mess up a guy just by touching him. And two! He became a humorless dick!"

    • by OG ( 15008 ) on Sunday March 29, 2009 @03:30PM (#27381139)

      I'd guess no. I believe it was V.S. Ramachandran who demonstrated that he could fool the brain into getting rid of phantom limb pain by using mirrors so that the visual system interpreted the remaining limb as being the missing limb (which leads into questions about blind people and phantom limbs, for which I don't have the answer and am too lazy to look it up). If one had an appendage that looked like an arm doing the things the brain was commanding the arm to do(and possibly requiring some tactile feedback as well), the brain would probably just interpret that appendage as the missing limb instead of creating a representation as a 3d arm.

      Or I could be totally wrong. Wouldn't be the first time.

    • In fact the kind of phantom limb studied in this article is not the kind most people are familiar with, due to amputation. This is a "supernumerary phantom limb". In SPL, the patient still has both arms, but after stroke experiences a third, additional arm. The nice thing about this methodologically is that they can compare imagination of movements with the existing paralyzed arm to the experienced movements of the SPL. How much of this applies to the more "typical" phantom limb is an important questi
    • and phantom limbs, i have a theory about ghosts:

      social contact is extremely important psychologically for human beings, especially in regard to close friends and family. we form social bonds with a small group of other humans who can finish our sentences and wordlessly engage in complex tasks with us. that our social connection with others in this small group can be said to be as strong and vital and deep and as complex and important for our survival as our psychological connection with our own hand or foot

  • by backwardMechanic ( 959818 ) on Sunday March 29, 2009 @02:50PM (#27380845) Homepage
    Vacuous lack of information? What's this 'scientists in Switzerland' rubbish? We may not be the biggest country, but it would be polite to say which scientists, even where. For anyone that cares, the study was led by Asaid Khateb, a neuropsychologist at Geneva University Hospitals. Published in the Annals of Nuerology, abstract here: []
    • Re: (Score:3, Insightful)

      by MightyYar ( 622222 )

      You clearly know how hyperlinking works, so what are you complaining about? Or is the slashdot summary supposed to contain all information that might be interesting to anyone? TFA is pretty heavily linked to the sources... anyone who cares will find the study authors.

      • I'm complaining about the article, not the /. summary. Is it too much to expect that the article itself might name the PI and reference the abstract, rather than link directly to the press release?
        • Re: (Score:3, Informative)

          by MightyYar ( 622222 )

          Gotcha, sorry I was snarky.

          But the bottom of the article does say "The study was led by Asaid Khateb of Geneva University Hospitals and was published in a recent issue of Annals of Neurology."

          I think the links to press releases are because that site ( seems to make it's money by funneling traffic to its clients, in this case apparently Just my guess :)

    • But the abstract you cite is even more vacuous. It reference patients, particularly a 'non-deluded woman', without even telling us what country they are in.

  • Intriguing. So, the more Metachlorians one has, the more one can control the body?
  • by crescente ( 1334029 ) on Sunday March 29, 2009 @03:10PM (#27381005)
    It's been long suspected in sports training that mentally practicing a skill is often as useful and productive as doing the real thing. fMRI supports this: [] The surprising thing to me is that she actually got relief from phantom-ly scratching herself. I suspect this is some placebo effect. Or related to why you can't tickle yourself.
    • by bwalling ( 195998 ) on Sunday March 29, 2009 @03:15PM (#27381037) Homepage
      I'm surprised by the relief from scratching as well. My dad lost part of a finger and finds that when he gets an itch that he perceives to be in the missing part, he cannot scratch it.
      • by cduffy ( 652 ) <> on Sunday March 29, 2009 @04:08PM (#27381401)

        You might find Phantoms in the Brain [] an interesting read. One of the items he mentions is that scratching an area near the missing limb in terms of the part of the brain responsible for interpreting its signals may allow one to scratch an itch in a phantom.

      • by yo303 ( 558777 )

        Yes, but your dad's itch was in his missing part. If you had read TFS, you would have read she scratched her head with her phantom limb. If where she had perceived an itch was in the missing part... no, you can't perceive with a missing head.

        She was asked to scratch her cheek. It wasn't a physical irritation, so it seems reasonable that the imagined itch could be relieved if the brain believed it was scratched.

        This would also be true for itches caused by nonverbal body language expression. Your brain wa

    • Re: (Score:3, Funny)

      by Yetihehe ( 971185 )
      I've just tried virtually scratching my head, but it didn't help. It really is only a placebo effect.
    • More related to why you can't tickle yourself. It is pretty well established now that the brain is in the business of predicting sensory events. With regards to touch, the activations in somatosensory cortex are very similar when you anticipate touch compared with when you actually experience it.
    • Which is speculated to be the purpose of dreaming
    • consider this new yorker piece: []

      basically, this poor woman's condition has bolstered neurologists rethinking of the itch sensation as something completely unrelated to pain. she had an incredibly rare "phantom itch". how disabling was it? she scratched THROUGH HER SKULL, until she was scratching brain matter

      she survived, in a debilitated condition, but she did better than her roommate, who, with a similar phantom itch, scratched through to his carotid, and killed himself

      read, for an especially horrifying insight into what its like to live with a phantom itch:

      "But I was desperate," M. told me. She let them operate on her, slicing the supraorbital nerve above the right eye. When she woke up, a whole section of her forehead was numb--and the itching was gone. A few weeks later, however, it came back, in an even wider expanse than before. The doctors tried pain medications, more psychiatric medications, more local anesthetic. But the only thing that kept M. from tearing her skin and skull open again, the doctors found, was to put a foam football helmet on her head and bind her wrists to the bedrails at night.

      She spent the next two years committed to a locked medical ward in a rehabilitation hospital--because, although she was not mentally ill, she was considered a danger to herself. Eventually, the staff worked out a solution that did not require binding her to the bedrails. Along with the football helmet, she had to wear white mitts that were secured around her wrists by surgical tape. "Every bedtime, it looked like they were dressing me up for Halloween--me and the guy next to me," she told me.

      "The guy next to you?" I asked. He had had shingles on his neck, she explained, and also developed a persistent itch. "Every night, they would wrap up his hands and wrap up mine." She spoke more softly now. "But I heard he ended up dying from it, because he scratched into his carotid artery."

      I met M. seven years after she'd been discharged from the rehabilitation hospital. She is forty-eight now. She lives in a three-room apartment, with a crucifix and a bust of Jesus on the wall and the low yellow light of table lamps strung with beads over their shades. Stacked in a wicker basket next to her coffee table were Rick Warren's "The Purpose Driven Life," People, and the latest issue of Neurology Now, a magazine for patients. Together, they summed up her struggles, for she is still fighting the meaninglessness, the isolation, and the physiology of her predicament.

      She met me at the door in a wheelchair; the injury to her brain had left her partially paralyzed on the left side of her body. She remains estranged from her children. She has not, however, relapsed into drinking or drugs. Her H.I.V. remains under control. Although the itch on her scalp and forehead persists, she has gradually learned to protect herself. She trims her nails short. She finds ways to distract herself. If she must scratch, she tries to rub gently instead. And, if that isn't enough, she uses a soft toothbrush or a rolled-up terry cloth. "I don't use anything sharp," she said. The two years that she spent bound up in the hospital seemed to have broken the nighttime scratching. At home, she found that she didn't need to wear the helmet and gloves anymore.

    • I'm continually surprised at how things are explained away by the scientific establishment as being "the placebo effect," because the placebo effect is really quite extraordinary, and only seems otherwise because of its prevalence. I mean, really, if someone takes sugar pills not knowing that they are just sugar pills and experiences the painkiller effects of morphine or cancer remission, or even side effects like nausea and headaches (all of which are documented examples), how is it even acceptable to jus

  • Could be useful (Score:5, Interesting)

    by MWoody ( 222806 ) on Sunday March 29, 2009 @03:17PM (#27381049)

    Now that they've found it, I'd like to see if they could - though I understand such specific manipulation is no doubt a long way off - work on a way to stimulate the area artificially. The ability to build controllable phantom limbs could be of great use for interacting with virtual realities. Imagine, while still having full control of your senses and limbs, being able to walk around a second entirely separate world with an entirely separate body; a lucid, computer-assisted daydream, essentially.

    • Well, the phantom limb comes from having had a limb lopped off. I don't know about you, but I'd rather keep all of my limbs in real life than start chopping them off to play second life. (I haven't read the article. If I am wrong and it's an additional limb, fair does, and a cool idea)
    • by Kelbear ( 870538 )

      Can't really go google-digging for a link at work, but I remember an experiment called "Avatar" where a guy rigged a camera-mount to point down at him like in a third-person game. The video feed would play in a helmet he wore. So essentially, he was looking down at himself when he wore the suit. It shifted his sense of location away from his head to several feet behind and above him.

      Some other experiment(or perhaps the same one?) also used a video feed to replace the subject's viewpoint to a camera's positi

  • A serious question (Score:5, Interesting)

    by Anonymous Coward on Sunday March 29, 2009 @03:31PM (#27381149)

    Do male to female transexuals get phantom erections after the operation?

    • by Anonymous Coward on Sunday March 29, 2009 @03:35PM (#27381193)

      Yes, we do.

      I'm just coming up to 3 years post-op. I no-longer get a phantom penis when awake, but I sometimes have something I call "the hermaphrodite dream", where I have both a penis and vagina. The first few times, it messed with my head a bit, but now I'm kinda OK with it, and it only happens once or twice a year.

      • by value_added ( 719364 ) on Sunday March 29, 2009 @05:06PM (#27381783)

        I'm just coming up to 3 years post-op.

        Hopefully that's not a recommendation. I'd imagine if the average Slashdotter had their own breasts to fondle, they'd never leave their basements.

      • Re: (Score:3, Funny)

        by Hognoxious ( 631665 )

        I sometimes have something I call "the hermaphrodite dream", where I have both a penis and vagina.

        Ob: well you can go and fuck yourself!

    • Do male to female transexuals get phantom erections after the operation?


      But I just did, thinking about it.


    • Re: (Score:3, Insightful)

      by Renraku ( 518261 )

      Phantom limb usually happens in people that suddenly lose a limb. Like they wake up in the hospital after a particularly vicious night of drinking and are missing their arm or leg. Or they get their arm blown off in whichever war is currently being called 'the war'

      It mostly stems from the brain's need to be able to tell the exact position of limbs in relation to the rest of the body.

      The penis, usually being several inches long, is not at the top of the brain's priority when it comes to this. As a male, I

      • Re: (Score:3, Funny)

        by Schemat1c ( 464768 )

        As a male, I can safely say that I have no idea what direction my penis is currently facing,

        I do 'cause I can feel it touching my ankle.

  • by gigamonkey ( 973801 ) on Sunday March 29, 2009 @03:32PM (#27381161) Journal
    Watch this guy explain it and be amazed. The phantom Limb part comes in at around half way if I remember correctly. This was filmed in 2007 so ya old news. Vilayanur Ramachandran: A journey to the center of your mind []
  • what's it thinking?

    And if it is thinking, doesn't that prove Descartes wrong?

  • I hope they find a way for me to install one of these phantom limbs.

    Preferably an arm so I can scratch myself while carrying two cups of coffee..

  • Damn!

    (and damn the lameness filter, too!)

  • by MarkKnopfler ( 472229 ) on Sunday March 29, 2009 @04:55PM (#27381725)

    Finally reaches the human brain...


  • I only opened this article to read the ensuing Venture Bros. jokes, and no one managed to post any with +3 or better moderation. Reanimated corpse slugs could have done better. Slashdot, you've failed me for the... well, neither first nor last time... but you've still failed me.
  • a lot of people suffer from it

    there are many kinds of tinnitus, but the most common, the persistent ringing that i suffer from and a lot of others do , is, in fact, a form of phantom limb phenomenon

    tinnitus is deafness, except just like that lost hand or that lost foot, sometimes the body maps the lack of information from that dead inner ear cell to the permanent "on" position, to tinnitus sufferer's permanent torture

    so any research on phantom limbs is important to a lot more people reading this than the ex

  • about people with psychic arms called Elfen Lied. Never watch it. It's horrible. People who say it's good are the same kind of people who say "smell my fart". The music is nice though.
    • I've seen the first couple of episodes, and while it was extremely random and somewhat unpretty, the bit where the girl says "nuuuuu" and rubs the main male character's hand on her tit has become somewhat of a recurring meme for my wife and I... so it's not all bad. :)
  • Even weirder... (Score:1, Interesting)

    by Deiouss ( 679628 )

    I once experienced something almost exactly like a phantom limb. After an episode of sleep paralysis laying on the couch on the third floor of my university library, I suddenly regained control of my arms. I was unable to open even my eyes...but I had complete control of my hands and arms. Eventually I reached up and touched my face, only to discover that there was no opposite sensation from the skin on my face. I was able to feel my hair and the features of my face, but my face felt as if it had been compl

  • to find a way to use that knowledge to build better direct neural interfaces between machine and man.

"An organization dries up if you don't challenge it with growth." -- Mark Shepherd, former President and CEO of Texas Instruments