Abstract
Motor cortical areas from both hemispheres play a role during functional recovery after a unilateral spinal cord injury (SCI). However, little is known about the morphologic and phenotypical differences that a SCI could trigger in corticospinal (CS) neurons of the ipsilesional and contralesional hemisphere. Using an SMI-32 antibody which specifically labeled pyramidal neurons in cortical Layers V, we investigated the impact of a unilateral cervical cord lesion on the rostral part (F6) and caudal part (F3) of the supplementary motor area (SMA) in both hemispheres of eight adult macaque monkeys compared with four intact control monkeys. We observed in F3 (but not in F6) interindividual variable and adaptive interhemispheric asymmetries of SMI-32-positive Layer V neuronal density and dendritic arborization, which are strongly correlated with the extent of the SCI as well as the duration of functional recovery, but not with the extent (percentage) of functional recovery.
- corticospinal projections
- interhemispheric asymmetry
- non-human primate
- pyramidal neurons
- spinal cord injury
- supplementary motor area
Footnotes
The authors declare no competing financial interests.
This work was supported by Swiss National Science Foundation Grants 31-61857.00, 310000-110005, 31003A-132465, and 310030B-149643 (to E.M.R.) and 320030-160229 (to E.S.); the National Centre of Competence in Research on “Neural Plasticity and Repair”; the Novartis Foundation; The Christopher Reeves Foundation (Springfield, NJ); and The Swiss Primate Competence Centre for Research.
This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International license, which permits unrestricted use, distribution and reproduction in any medium provided that the original work is properly attributed.
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