Nandakumar Bharadwaj, Blumenthal Gary H, Disse Gregory D, Desmond Pierce C, Ebinu Julius O, Ricard Jerome, Bethea John R, Moxon Karen A
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.
Neuroscience Graduate Program, University of California, Davis, CA 95616, USA.
Exp Neurol. 2023 Jun;364:114394. doi: 10.1016/j.expneurol.2023.114394. Epub 2023 Mar 29.
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.
姿势控制对于运动至关重要,它能实现步态变化、避障以及在崎岖地形中导航。脊髓损伤(SCI)后的一个主要问题是重新获得平衡控制以防止跌倒和进一步损伤。虽然运动模式生成的神经回路位于脊髓,但姿势控制由多个复杂网络组成,这些网络在脊髓、脑干和皮层水平相互作用。完全性脊髓损伤后,皮层重组建立了对体重支撑步行所需的躯干肌肉组织的新控制。在本研究中,我们在大鼠中度和重度胸段中部挫伤损伤这两种更具临床相关性的模型中,研究了运动疗法对皮层重组的影响。结果表明,自发恢复和治疗诱导的体重支撑步行恢复均利用了皮层重组。此外,运动疗法通过增强对下胸部肌肉的皮层控制进一步改善结果,从而改善与平衡改善相关的肢体间协调性,进而增加体重支撑步行。本研究结果表明,姿势的皮层控制是运动功能改善的关键。通过考虑整个神经轴上的变化,这些信息可用于改善脊髓损伤后的治疗时机和类型。