Tuesday, October 21, 2008

Changes in sensory mapping of the brain

We all know about sensory mapping of the brain, right. Somatic senses detected on the right side of the body are processed in the somatic sensory area of the cortex in the left hemisphere . . . all mapped out in a way that can be represented in a homunculus or little map of the body transposed on the cortex. The image shown here is a snapshot of a three-dimensional homunculus on exhibit at the London Natural History Museum. Or the 2-D homunculus shown in Chapter 14 of my textbook Anatomy & Physiology.

And we all know that plasticity of brain function allows us to reorganize the sensory map of the brain when we lose a body part . . . as in an accidental amputation. (Yet another reason to be careful when dissecting specimens, eh?)

A recent article in the journal Current Biology tells us that a man who received a hand transplant several decades after an accidental amputation experienced a reactivation of the old "hand map" within his sensory cortex. In other words, his brain went back to the original pre-amputation configuration.

. . . a nice little bit of current research to throw into your next discussion of the concepts of sensory mapping and plasticity.

Check out these resources:

Chronically deafferented sensory cortex recovers a grossly typical organization following allogenic hand transplantation
By Frey, S., et al.
October 14, 2008, Current Biology, vol. 18, no. 19, p. 1530-1534, doi:10.1016/j.cub.2008.08.051
(original article; summary is FREE; article contains interesting images)

Science News Web edition : Thursday, October 9th, 2008
(great FREE summary and interpretation of the findings; has photos of the subject)

handtransplant.com com
(site about hand transplants)

Hand transplant video
(YouTube video with the story of a hand transplant . . . can't be embedded)

For "something completely different," there's this odd video that parodies the fringe hypothesis that a transplanted organ may carry with it memories of the donor . . .

[If you don't see the video viewer in your newsletter or feed version of this article, please go to The A&P Professor blog site to view it.]

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