pain centers? (Phantom Limbs)

x011 at Lehigh.EDU x011 at Lehigh.EDU
Mon Mar 20 08:30:34 EST 1995


In article <3kcg5f$eq8 at cat.cis.Brown.EDU>, ST004131 at brownvm.brown.edu (Justin Ba
ker) writes:
>Regarding the cause of sensation associated with phantom limbs, I am
>fairly confident that it has little to do with any direct signal or
>lack of signal from the limb.  Rather, the sensation is the result of
>stimulation of mechanoreceptors at places in the body that map onto the
>primary sensory cortex in areas adjacent to those areas mapped by the phantom
>limb.  Along the sensory cortex, the body is not always mapped according to
>hip-bone connected to the leg-bone logic.  Thus, a stimulation of an
>amputee's cheek could very well make his prosthesis tingle.
>
>Justin Baker
>Brown University
>
Pain is a complex issue.  This can be illustrated with an illusion of pain.
Paradoxical integration is illustrated with the Thunberg thermal grill
illusion.  Using alternating tubes of warm and cold water to generate
contradictory stimulation individuals report intense pain.  Craig and
Bushnell, 1994 suggest that the integration in the thalamic region of
the brain best explains this illusion.  The integration result from the
joining of two unmasked simple models of central disinhibition.

Ron Blue
Reference:
Craig, A.D. & Bushnell, M.C. (1994, July 8).  The Thermal Grill
Illusion: Unmasking the Burn of Cold Pain. Science v265, p252(4).





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