Learning to use your new prehensile tail…

The obscure title is aimed at a friend who’s always sworn that, when it comes time to choose body modifications, he wants that prehensile tail.

And now, according to some new research published in PNAS last week, he can learn to use it before he even has it!

(Note: the article I read about this can be found here - unfortunately, I don’t seem to be able to find the paper itself anywhere on the PNAS site…)

Researchers have been looking into the idea of phantoms: no, not pale forms inhabiting dark corners, but instead limbs that we can feel attached to us, even when they aren’t. The most common form of this is after an amputation, when many amputees continue to feel the limb after the surgery and not in a good way, either - apparently, it is often quite painful.

Previous research has looked into how best to treat phantom pain, but now, scientists have gone one better: they successfully managed to get people who have lost a limb - in this case, an arm above the elbow - were able to learn to manipulate the lost limb in entirely impossible ways. Apparently, those who were successful described that their wrist had developed a new joint, and the researchers were able to corroborate that, at least as fair as the patients’ brains were concerned, the new neural pathways had in fact been produced (rather than being faked).

“Seven people who had an arm that had been amputated above the elbow were encouraged to learn a particular arm movement that defies biomechanics — turning a hand that’s bent 90 degrees at the wrist the last quarter of a full turn that the hand won’t do. The study participants practiced by imagining that they were moving the phantom limb for five minutes per hour every day until they had achieved the impossible movement or had given up (this took one to four weeks depending on the individual). Four of the participants were successful in feeling the sensation of the impossible movement, the researchers report.”

“Each of the participants who achieved the impossible move also described developing a new wrist joint that allowed the impossible movement. And three of the four reported that moves that were previously possible for the phantom limb were now difficult with their new wrist.”

So yes - it has implications for a number of things, from people learning to use new body parts before they can access them physically, or even to readjust self-image (very useful for people with conditions such as anorexia).

And for learning to use that prehensile tail :)

  • Grant Jacobs

    I think this is what you want:

    It’s still under Early Edition, i.e. on-line in advance of print. Not open access.

  • Aimee Whitcroft

    Excellent, thanks :) I really did look, but having said that, am also very good at looking directly at things and not seeing them sometimes (I hope it’s not a metaphor for something)…

  • Grant Jacobs

    I know what you mean! I’m forever finding that I’ve missed a paper on the journals I scan… I do a sort-of cross-indexing approach now to avoid the worst of it.

    I don’t know about you, but I find it harder to read on computer screens. Might be the glare or something. (Don’t say it’s because I’m getting older… hehe.)