Plasticity

Ed Ergenzinger ergenzin at bgsm.edu
Tue Jun 2 10:44:11 EST 1998



Gernot S Doetsch wrote:

>    Much has recently been written about the plasticity of adult brains. Following peripheral denervation or sensorimotor training, significant changes can occur in the response properties of cortical neurons and the details of somatosensory and motor cortical maps. Do such physiological changes mean that the sensory or motor function of the affected neurons has changed accordingly? Can the "behavioral function" of adult mammalian neurons ever change? If so, under what circumstances?
>     I welcome any comments on these issues.    GSD

I believe that your questions relate to the perceptual consequences of adult plasticity.  In the somatosensory system perceptual anomalies such as
phantom limb have been linked to reorganizational changes following
injury.  The association between phantom sensation and reorganized
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.  How this interpretation process occurs cuts to the heart of how sensory systems "perceive" and interpret sensory information.  It is almost as though there is a developmental window akin to a critical period during which neurons become
"addressed" such that their activity is forever associated with the stimulation of a specific region of the body surface.  While changes in receptive field organization can occur, the system as a whole does not readdress those cells, leading to mislocalization and phantoms.





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