The Journal of Neuroscience, September 1, 1999, 19(17):7578-7590
Evidence for Brainstem and Supra-Brainstem Contributions to Rapid
Cortical Plasticity in Adult Monkeys
J.
Xu and
J. T.
Wall
Department of Neurobiology and Anatomy, Medical College of Ohio,
Toledo, Ohio 43699-0008
Cortical maps can undergo amazingly rapid changes after injury of
the body. These changes involve functional alterations in normal
substrates, but the cortical and/or subcortical location(s) of these
alterations, and the relationships of alterations in different
substrates, remain controversial. The present study used
neurophysiological approaches in adult monkeys to evaluate how
brainstem organization of tactile inputs in the cuneate nucleus (CN)
changes after acute injury of hand nerves. These data were then
compared with analogous data from our earlier cortical area 3b studies,
which used the same approaches and acute injury, to assess
relationships of cuneate and cortical changes. The results indicate
that cuneate tactile responsiveness, receptive field locations,
somatotopic organization, and spatial properties of representations
(i.e., location, continuity, size) change during the first minutes to
hours after injury. The comparisons of cuneate and area 3b organization
further show that some cuneate changes are preserved in area 3b,
whereas other cuneate changes are transformed before being expressed in
area 3b. The findings provide evidence that rapid reorganization in
area 3b, in part, reflects mechanisms that operate from a distance in
the cuneate nucleus and, in part, reflects supracuneate mechanisms that
modify brainstem changes.
Key words:
neuronal plasticity; somatosensory cortex; dorsal column
nuclei; lemniscal mechanisms; disinhibition; sensitization; tactile
processing; primate cuneate nucleus
Copyright © 1999 Society for Neuroscience 0270-6474/99/19177578-13$05.00/0
Previous Article | Next Article
