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Disability, atrophy and cortical reorganization following spinal cord injury.

Freund P, Weiskopf N, Ward NS, Hutton C, Gall A, Ciccarelli O, Craggs M, Friston K, Thompson AJ - Brain (2011)

Bottom Line: Subjects with spinal cord injury had impaired upper and lower limb function bilaterally, a 30% reduced cord area, smaller white matter volume in the pyramids and left cerebellar peduncle, and smaller grey matter volume and cortical thinning in the leg area of the primary motor and sensory cortex compared with controls.In conclusion, spinal cord injury leads to cord atrophy, cortical atrophy of primary motor and sensory cortex, and cortical reorganization of the sensorimotor system.The degree of cortical reorganization is predicted by spinal atrophy and is associated with significant disability.

View Article: PubMed Central - PubMed

Affiliation: Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, UCL, Queen Square, London WC1N 3BG, UK. p.freund@ion.ucl.ac.uk

ABSTRACT
The impact of traumatic spinal cord injury on structural integrity, cortical reorganization and ensuing disability is variable and may depend on a dynamic interaction between the severity of local damage and the capacity of the brain for plastic reorganization. We investigated trauma-induced anatomical changes in the spinal cord and brain, and explored their relationship to functional changes in sensorimotor cortex. Structural changes were assessed using cross-sectional cord area, voxel-based morphometry and voxel-based cortical thickness of T1-weighted images in 10 subjects with cervical spinal cord injury and 16 controls. Cortical activation in response to right-sided (i) handgrip; and (ii) median and tibial nerve stimulation were assessed using functional magnetic resonance imaging. Regression analyses explored associations between cord area, grey and white matter volume, cortical activations and thickness, and disability. Subjects with spinal cord injury had impaired upper and lower limb function bilaterally, a 30% reduced cord area, smaller white matter volume in the pyramids and left cerebellar peduncle, and smaller grey matter volume and cortical thinning in the leg area of the primary motor and sensory cortex compared with controls. Functional magnetic resonance imaging revealed increased activation in the left primary motor cortex leg area during handgrip and the left primary sensory cortex face area during median nerve stimulation in subjects with spinal cord injury compared with controls, but no increased activation following tibial nerve stimulation. A smaller cervical cord area was associated with impaired upper limb function and increased activations with handgrip and median nerve stimulation, but reduced activations with tibial nerve stimulation. Increased sensory deficits were associated with increased activations in the left primary sensory cortex face area due to median nerve stimulation. In conclusion, spinal cord injury leads to cord atrophy, cortical atrophy of primary motor and sensory cortex, and cortical reorganization of the sensorimotor system. The degree of cortical reorganization is predicted by spinal atrophy and is associated with significant disability.

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Statistical parametric maps (thresholded at P < 0.001, uncorrected for display purposes only) showing regions of increased task-related brain activity in subjects with SCI compared with controls. (A) Increased BOLD response during right-sided handgrip in contralateral left leg area of primary motor cortex and (B) during right-sided median nerve stimulation in contralateral left face area of primary sensory cortex.
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Figure 5: Statistical parametric maps (thresholded at P < 0.001, uncorrected for display purposes only) showing regions of increased task-related brain activity in subjects with SCI compared with controls. (A) Increased BOLD response during right-sided handgrip in contralateral left leg area of primary motor cortex and (B) during right-sided median nerve stimulation in contralateral left face area of primary sensory cortex.

Mentions: Subjects with SCI exhibited relative increases in task-related BOLD signal in left superior, medial precentral gyrus consistent with the leg representation within primary motor cortex compared with controls (P = 0.006, corrected for multiple comparisons within region of interest) (Fig. 5A, Supplementary Table 2). Linear regression analyses revealed an association between lower cord area and greater task-related BOLD signal during right handgrip in the leg area of primary motor cortex (P = 0.005, corrected for multiple comparisons within region of interest) (Fig. 6A, Table 3). In other words, task-related brain activation was greater in left primary motor cortex (leg) in subjects with SCI with greater cord damage.Figure 5


Disability, atrophy and cortical reorganization following spinal cord injury.

Freund P, Weiskopf N, Ward NS, Hutton C, Gall A, Ciccarelli O, Craggs M, Friston K, Thompson AJ - Brain (2011)

Statistical parametric maps (thresholded at P < 0.001, uncorrected for display purposes only) showing regions of increased task-related brain activity in subjects with SCI compared with controls. (A) Increased BOLD response during right-sided handgrip in contralateral left leg area of primary motor cortex and (B) during right-sided median nerve stimulation in contralateral left face area of primary sensory cortex.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3102242&req=5

Figure 5: Statistical parametric maps (thresholded at P < 0.001, uncorrected for display purposes only) showing regions of increased task-related brain activity in subjects with SCI compared with controls. (A) Increased BOLD response during right-sided handgrip in contralateral left leg area of primary motor cortex and (B) during right-sided median nerve stimulation in contralateral left face area of primary sensory cortex.
Mentions: Subjects with SCI exhibited relative increases in task-related BOLD signal in left superior, medial precentral gyrus consistent with the leg representation within primary motor cortex compared with controls (P = 0.006, corrected for multiple comparisons within region of interest) (Fig. 5A, Supplementary Table 2). Linear regression analyses revealed an association between lower cord area and greater task-related BOLD signal during right handgrip in the leg area of primary motor cortex (P = 0.005, corrected for multiple comparisons within region of interest) (Fig. 6A, Table 3). In other words, task-related brain activation was greater in left primary motor cortex (leg) in subjects with SCI with greater cord damage.Figure 5

Bottom Line: Subjects with spinal cord injury had impaired upper and lower limb function bilaterally, a 30% reduced cord area, smaller white matter volume in the pyramids and left cerebellar peduncle, and smaller grey matter volume and cortical thinning in the leg area of the primary motor and sensory cortex compared with controls.In conclusion, spinal cord injury leads to cord atrophy, cortical atrophy of primary motor and sensory cortex, and cortical reorganization of the sensorimotor system.The degree of cortical reorganization is predicted by spinal atrophy and is associated with significant disability.

View Article: PubMed Central - PubMed

Affiliation: Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, UCL, Queen Square, London WC1N 3BG, UK. p.freund@ion.ucl.ac.uk

ABSTRACT
The impact of traumatic spinal cord injury on structural integrity, cortical reorganization and ensuing disability is variable and may depend on a dynamic interaction between the severity of local damage and the capacity of the brain for plastic reorganization. We investigated trauma-induced anatomical changes in the spinal cord and brain, and explored their relationship to functional changes in sensorimotor cortex. Structural changes were assessed using cross-sectional cord area, voxel-based morphometry and voxel-based cortical thickness of T1-weighted images in 10 subjects with cervical spinal cord injury and 16 controls. Cortical activation in response to right-sided (i) handgrip; and (ii) median and tibial nerve stimulation were assessed using functional magnetic resonance imaging. Regression analyses explored associations between cord area, grey and white matter volume, cortical activations and thickness, and disability. Subjects with spinal cord injury had impaired upper and lower limb function bilaterally, a 30% reduced cord area, smaller white matter volume in the pyramids and left cerebellar peduncle, and smaller grey matter volume and cortical thinning in the leg area of the primary motor and sensory cortex compared with controls. Functional magnetic resonance imaging revealed increased activation in the left primary motor cortex leg area during handgrip and the left primary sensory cortex face area during median nerve stimulation in subjects with spinal cord injury compared with controls, but no increased activation following tibial nerve stimulation. A smaller cervical cord area was associated with impaired upper limb function and increased activations with handgrip and median nerve stimulation, but reduced activations with tibial nerve stimulation. Increased sensory deficits were associated with increased activations in the left primary sensory cortex face area due to median nerve stimulation. In conclusion, spinal cord injury leads to cord atrophy, cortical atrophy of primary motor and sensory cortex, and cortical reorganization of the sensorimotor system. The degree of cortical reorganization is predicted by spinal atrophy and is associated with significant disability.

Show MeSH
Related in: MedlinePlus