F. Frank LeFever flefever at ix.netcom.com
Sun Jun 7 00:32:39 EST 1998

In a very general sense, perhaps, although we have at lest inmplicitly
been considering cortical reorganization and site for chronic pain may
be thalamus or spinal cord (either or both? depending on type, etc.?)

There is a growing literature on central (Usually but not always
central = spinal cord) changes due to peripheral pain, involving
substance P, IL-1, NO, resulting in more-or-less permanent changes in
pain response if not actual spontaneous pain activity.  I think this
probably refers to enhanced excitability more than reorganization;,
HOWEVER,  I believe that in one paradigm a fairly localized insult
(e.g. formalin in one paw) can cause an enhancement so general that
pain responses to stimulation over the entire body is enhanced.

F. Frank LeFever, Ph.D.
New York Neuropsychology Groupp

In <6lb3ph$5ur$1 at news2.xs4all.nl> "DK" <cooper17 at nospam.xs4all.nl>
>I have read that some types of chronic pain can persist long
>after there is no clear indication for it. It seems the body can
>"learn" pain if given enough time to associate with it. Could the
>below snip also explain this?
>Ed Ergenzinger wrote in message <35741D3E.90C81D67 at bgsm.edu>...
>>  In the somatosensory system perceptual anomalies such as
>>phantom limb have been linked to reorganizational changes
>>injury.  The association between phantom sensation and
>>central maps would seem to indicate that while neurons can
>acquire new receptive fields and become activated by input from
>new portions of the body surface, the result of this activity is
>interpreted as coming from old portions of the body surface.

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