Journal article
Hand Motor Recovery Following Extensive Frontoparietal Cortical Injury Is Accompanied by Upregulated Corticoreticular Projections in Monkey
The Journal of neuroscience, Vol.38(28), pp.6323-6339
07/11/2018
DOI: 10.1523/JNEUROSCI.0403-18.2018
PMCID: PMC6041795
PMID: 29899028
Abstract
We tested the hypothesis that arm/hand motor recovery after injury of the lateral sensorimotor cortex is associated with upregulation of the corticoreticular projection (CRP) from the supplementary motor cortex (M2) to the gigantocellular reticular nucleus of the medulla (Gi). Three groups of rhesus monkeys of both genders were studied: five controls, four cases with lesions of the arm/hand area of the primary motor cortex (M1) and the lateral premotor cortex (LPMC; F2 lesion group), and five cases with lesions of the arm/hand area of M1, LPMC, S1, and anterior parietal cortex (F2P2 lesion group). CRP strength was assessed using high-resolution anterograde tracers injected into the arm/hand area of M2 and stereology to estimate of the number of synaptic boutons in the Gi. M2 projected bilaterally to the Gi, primarily targeting the medial Gi subsector and, to a lesser extent, lateral, dorsal, and ventral subsectors. Total CRP bouton numbers were similar in controls and F2 lesion cases but F2P2 lesion cases had twice as many boutons as the other two groups (
p
= 0.0002). Recovery of reaching and fine hand/digit function was strongly correlated with estimated numbers of CRP boutons in the F2P2 lesion cases. Because we previously showed that F2P2 lesion cases experience decreased strength of the M2 corticospinal projection (CSP), whereas F2 lesion monkeys experienced increased strength of the M2 CSP, these results suggest one mechanism underlying arm/hand motor recovery after F2P2 injury is upregulation of the M2 CRP. This M2-CRP response may influence an important reticulospinal tract contribution to upper-limb motor recovery following frontoparietal injury.
SIGNIFICANCE STATEMENT
We previously showed that after brain injury affecting the lateral motor cortex controlling arm/hand motor function, recovery is variable and closely associated with increased strength of corticospinal projection (CSP) from an uninjured medial cortical motor area. Hand motor recovery also varies after brain injury affecting the lateral sensorimotor cortex, but medial motor cortex CSP strength decreases and cannot account for recovery. Here we observed that motor recovery following sensorimotor cortex injury is closely associated with increased strength of the descending projection from an uninjured medial cortical motor area to a brainstem reticular nucleus involved in control of arm/hand function, suggesting an enhanced corticoreticular projection may compensate for injury to the sensorimotor cortex to enable recovery of arm/hand motor function.
Details
- Title: Subtitle
- Hand Motor Recovery Following Extensive Frontoparietal Cortical Injury Is Accompanied by Upregulated Corticoreticular Projections in Monkey
- Creators
- Warren G Darling - Department of Health and Human Physiology, Motor Control LaboratoriesJizhi Ge - Division of Basic Biomedical Sciences, Laboratory of Neurological Sciences, University of South Dakota, Sanford School of Medicine, Vermillion, South Dakota 57069Kimberly S Stilwell-Morecraft - Division of Basic Biomedical Sciences, Laboratory of Neurological Sciences, University of South Dakota, Sanford School of Medicine, Vermillion, South Dakota 57069Diane L Rotella - Department of Health and Human Physiology, Motor Control LaboratoriesMarc A Pizzimenti - Department of Anatomy and Cell Biology, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242, andRobert J Morecraft - Division of Basic Biomedical Sciences, Laboratory of Neurological Sciences, University of South Dakota, Sanford School of Medicine, Vermillion, South Dakota 57069
- Resource Type
- Journal article
- Publication Details
- The Journal of neuroscience, Vol.38(28), pp.6323-6339
- Publisher
- Society for Neuroscience
- DOI
- 10.1523/JNEUROSCI.0403-18.2018
- PMID
- 29899028
- PMCID
- PMC6041795
- ISSN
- 0270-6474
- eISSN
- 1529-2401
- Language
- English
- Date published
- 07/11/2018
- Academic Unit
- Anatomy and Cell Biology; Physical Therapy and Rehabilitation Science; Health and Human Physiology
- Record Identifier
- 9984002491902771
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