Plasticity

Ed Ergenzinger ergenzin at bgsm.edu
Tue Jun 2 14:33:52 EST 1998


>   I agree completely that following denervation, the "function" of >somatosensory neurons does not seem to change, often leading to >sensation referred from new receptive fields to a phantom. However, >what about comparable changes in motor cortex? After denervation >(amputation) of a limb, stimulation of the cortical area previously >representing that limb usually elicits motor responses of proximal >muscle groups. Does this mean that the "function" of the activated >cortical neurons
has changed from limb to proximal muscles ? Or has >cortical output from functionally-unchanged "limb neurons" simply been >rerouted to motoneuron pools controlling proximal muscles?

If you ask an amputee to move the limb that has been lost, do they activate proximal muscle
groups? This would seem to support the idea that the neurons are functionally-unchanged
but have been rerouted to motoneuron pools controlling proximal muscles.

>If so, no functional reorganization of motor cortex need have occurred. >What other possible interpretations are there?        GSD

I think you are using the term "functional" in a different context here.
-Ed








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