Exercise therapy guides cortical reorganization after midthoracic spinal contusion to enhance control of lower thoracic muscles, supporting functional recovery

Bharadwaj Nandakumar; Gary H Blumenthal; Gregory D Disse; Pierce C Desmond; Julius O Ebinu; Jerome Ricard; John R Bethea; Karen A Moxon

doi:10.1016/j.expneurol.2023.114394

Exercise therapy guides cortical reorganization after midthoracic spinal contusion to enhance control of lower thoracic muscles, supporting functional recovery

Exp Neurol. 2023 Jun:364:114394. doi: 10.1016/j.expneurol.2023.114394. Epub 2023 Mar 29.

Authors

Bharadwaj Nandakumar¹, Gary H Blumenthal¹, Gregory D Disse², Pierce C Desmond³, Julius O Ebinu⁴, Jerome Ricard⁵, John R Bethea⁵, Karen A Moxon⁶

Affiliations

¹ Department of Biomedical Engineering, University of California, Davis, CA 95616, USA; School of Biomedical Engineering Science and Health Systems, Drexel University, Philadelphia, PA 19104, USA.
² Neuroscience Graduate Program, University of California, Davis, CA 95616, USA.
³ Department of Biomedical Engineering, University of California, Davis, CA 95616, USA.
⁴ Department of Neurological Surgery, University of California, Davis, CA 95616, USA.
⁵ School of Biomedical Engineering Science and Health Systems, Drexel University, Philadelphia, PA 19104, USA.
⁶ Department of Biomedical Engineering, University of California, Davis, CA 95616, USA; Neuroscience Graduate Program, University of California, Davis, CA 95616, USA; Department of Neurological Surgery, University of California, Davis, CA 95616, USA. Electronic address: moxon@ucdavis.edu.

PMID: 37001630
DOI: 10.1016/j.expneurol.2023.114394

Abstract

Postural control is critical for locomotion, allowing for gait changes, obstacle avoidance and navigation of rough terrain. A major problem after spinal cord injury (SCI) is regaining the control of balance to prevent falls and further injury. While the circuits for locomotor pattern generation reside in the spinal cord, postural control consists of multiple, complex networks that interact at the spinal, brainstem and cortical levels. After complete SCI, cortical reorganization establishes novel control of trunk musculature that is required for weight-supported stepping. In this study, we examined the impact of exercise therapy on cortical reorganization in the more clinically relevant models of both moderate and severe midthoracic contusion injury in the rat. Results demonstrate that both spontaneous recovery and therapy induced recovery of weight-supported stepping utilize cortical reorganization. Moreover, exercise therapy further improves outcome by enhancing cortical control of lower thoracic muscles enabling improvements in interlimb coordination associated with improved balance that increases weight-supported stepping. The outcome of this study suggest that cortical control of posture is key to functional improvement in locomotion. This information can be used to improve the timing and type of therapy after SCI by considering changes along the entire neural axis.

Keywords: Cortical plasticity; ICMS; Physical exercise; Rodent; Spinal cord injury; Treadmill; Trunk.

Publication types

Research Support, U.S. Gov't, Non-P.H.S.
Research Support, N.I.H., Extramural

MeSH terms

Animals
Contusions*
Exercise Therapy / methods
Gait / physiology
Humans
Locomotion / physiology
Muscle, Skeletal
Rats
Recovery of Function
Spinal Cord Injuries* / therapy

Grants and funding

R01 NS096971/NS/NINDS NIH HHS/United States