Can a Limb That Never Existed Become a Phantom Limb?

By Sarah Zhang | March 12, 2012 2:59 pm

hand

Our brains sometimes just refuse to believe the truth. No, we’re talking not deniers or conspiracy theorists today—just phantom limbs.

If you ask RN, a 57-year-old woman, she would agree that she does not have a right hand: it was amputated after a bad car crash when she was 18. She would also tell you that she has never had a right index finger: she was born with a congenital deformity that gave her only the rudiment of a thumb, immobile ring and middle fingers, and no index finger at at all. More than 35 years after the amputation, she feels pain in a phantom right hand, which has five—not four—fully mobile fingers.

This latest case study recently published by Paul McGeoch and V.S. Ramachandran, leading brain scientists who study phantom limb syndrome, suggests the brain have an innate, hard-wired template for body image that is independent of what we see and feel. The authors say that most people born with congenitally missing limbs do not experience phantom ones, but a small subset do. Why that’s so is unclear, as is the origin of phantom limbs in general.

RN’s phantom phantom finger is similar to the supernumerary phantom limb, a condition in which patients report unusual, extra limbs that never existed and normally do not exist, such as a third arm. One 64-year-old librarian mentally “grew” a third arm after suffering from a brain hemorrhage. When researchers put her in a fMRI machine and told her to “move” that arm, her motor cortex lit up just as if she were moving a real arm. As far as the motor cortex of her brain is concerned, that arm is real.

It’s enough to make you double-check that all the limbs you’re feeling are actually there.

Image via Shutterstock / Quayside 

  • Anonymous

    Ignoring for a moment the woman who “grew” a third arm, and concentrating on the innate hard-wired image of the body concept, I wonder if at some point she did have a full hand and her brain wired itself accordingly and that some time after that, but before birth something else happened to her hand.  I believe the general consensus is that things just never are before birth (as in that hand was always going to become the way it was), but maybe that is not the case?  Maybe the people who feel that phantom limb that never was actually had it at some point?  

    For the lady who “grew” a third arm, that is just wow!  It always amazes me how little we really know about the brain and its hows and whys.  

    • http://sarzha.tumblr.com Sarah Zhang

      That’s definitely possible–the authors also write that she may have grown a full hand that was partially reabsorbed in utero. We have no way of knowing, but it certainly could be true.

  • http://www.facebook.com/people/Etienne-Manderscheid/4301233 Etienne Manderscheid

    I don’t believe the innate, hard-wired image of the body idea for a second. I doubt that is the authors’ conclusion as well. Alternative hypotheses are that the opposite hand, the feet or simply observing other people’s hands and feet normally contribute to how the brain constructs these artificial fingers/limbs.

    • http://1solutionfocusedcoaching.com/ Roberta Cone, Psy.D

      Etienne,

      The somatosensory cortex contains a map for every body part. Discovered by Canadian Neurosurgeon Wilder Penfield in the 1930’s and is known as the homunculus.  If an area in the somatosensory cortex is stimulated, the person will feel a sensation in the corresponding body part.  Recent research with fMRI suggests cortical reorganization is happening in cases of phantom limb sensation and pain.

    • http://sarzha.tumblr.com Sarah Zhang

      Why don’t you read the paper before commenting on what the authors did or did not say? 

  • Neuroreporter

    The article recently published by McGeoch and Ramachandran provides no information about when the  researchers evaluated the woman who reported phantom fingers. The most recent reference cited by their paper is 2000. A lot of research has been done in the last ten years and most of it does not support the theories about phantom limbs advanced by Ramachandran in the 1990s. As for the effectiveness of mirror therapy, the claim in this paper is dubious. Recent papers published by Lorimer Moseley and Herta Flor (two of the world’s leading pain researchers) point out that mirror therapy is not considered effective as an initial treatment. It is sometimes incorporated as a later stage of graded motor imagery. The information in this article appears to be very much out of date.

NEW ON DISCOVER
OPEN
CITIZEN SCIENCE
ADVERTISEMENT

Discover's Newsletter

Sign up to get the latest science news delivered weekly right to your inbox!

Discoblog

Quirky, funny, and surprising science news from the edge of the known universe.
ADVERTISEMENT

See More

ADVERTISEMENT
Collapse bottom bar
+

Login to your Account

X
E-mail address:
Password:
Remember me
Forgot your password?
No problem. Click here to have it e-mailed to you.

Not Registered Yet?

Register now for FREE. Registration only takes a few minutes to complete. Register now »