Apotemnophilia – the Neurological Basis of a ‘Psychological’ Disorder
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- Center for Brain and Cognition, University of California, San Diego
- Department of Radiology, University of California, San Diego
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- Manuscript
- Date:
- Received 17 March 2009 11:53 UTC; Posted 18 March 2009
- Subjects:
- Neuroscience
- Abstract:
The question of how the human brain combines disparate sensory inputs to construct a unified body image is of longstanding interest1,2,3 . We approached this subject by studying the unusual medical condition of apotemnophilia, in which otherwise mentally normal individuals express the strong and persistent desire for the amputation of a specific healthy limb4,5,6 . Here we show using functional brain imaging – magnetoencephalography (MEG) – that the condition is characterised by an absence of activity in the right superior parietal lobule (SPL) when the affected limb is touched. When this discovery is combined with our earlier finding of a simultaneous increase in skin conductance response (SCR) on touching the affected limb7 , which reflects increased sympathetic nervous system activity relating to the limb8 , we conclude that what has been regarded as a purely psychological condition, actually has a neurological basis and is caused by a failure to represent one or more limbs in the right SPL. This has the bizarre consequence that although sufferers can feel the affected limb being touched, it does not actually integrate into their body image – a mismatch that results in a desire for the affected limb to be amputated.
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2 comments
I just recently learned of this insideous disease / addiction / obsessive compulsion with longing to lop (“Bad limb!”) after reading ‘Brain Games’ in the May 11, 2009 issue of The New Yorker.
It’s a story on the so-called “Marco Polo of neuroscience,” Dr. Vilayanur Ramachandran.
The Indian-born behavioral neurologist is the Director of the Center for Brain and Cognition at UCSD, and, one who has had more than his share of exposure to the “lop it or leave it” crowd.
The piece is written by John Calopinto, a staff writer and author of “As Nature Made Him” and “About the Author.”
Fascinating, and, in the end, an illuminating look at this rare condition from a totally unique perspective.
Luckily for the good doctor, I don’t believe there’s much of a chance that his name will one day replace that of the venerable Venetian explorer when kids are hiding from one another at the local swimming pool.
Hell, I’d be thrilled if I could pronounce either half of the man’s moniker.
Wouldn’t it be the bomb if his colleagues called him something bitchin’ like, say, RAM-DRAN?
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- This document is licensed to the public under the Creative Commons Attribution 3.0 License
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McGeoch, Paul, Brang, David, Song, Tao, Lee, Roland, Huang, Mingxiong, and Ramachandran, Vilayanur. Apotemnophilia – the Neurological Basis of a ‘Psychological’ Disorder. Available from Nature Precedings <http://hdl.handle.net/10101/npre.2009.2954.1> (2009)
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Eric L on 08 April 2009 15:09 UTC
I am a neuroscience student studying this topic for a class. This is a great article that holds promise for changing many people’s perspectives on BIID. Many who have proposed purely psychological accounts of BIID have unfortunately ignored the second and third observations you make – that the location of desired amputation is specific and more often localized to the left side.
I am interested in your interpretation that the evidence for the neurological basis of the disorder excludes the possibility for lived experience inducing the disorder (for example, observing and identifying with an amputee early in life). Couldn’t such an experience alter the body image in a way that has neurological effects of the type you have observed? I know that with the work your lab has done on phantom limb syndrome, you are perhaps as qualified as any to speak about the functional plasticity that still exists in body representation after early development.
Also, I have read that some individuals with BIID do not desire to become amputees but instead, paralyzed, blind, deaf, etc. Do you believe that these desires could stem from a similar neurological dysfunction in the right superior parietal lobule, or is the etiology distinct in those cases?