School of Health Sciences, Western Sydney University, Campbelltown, New South Wales, Australia.
College of Nursing and Health Sciences, Flinders University, Adelaide, South Australia, Australia.
Brain Behav. 2020 Aug;10(8):e01702. doi: 10.1002/brb3.1702. Epub 2020 Jul 7.
Accumulating evidence suggests that motor skill training is associated with structural and functional reorganization of the primary motor cortex. However, previous studies have focussed primarily upon the upper limb, and it is unclear whether comparable reorganization occurs following training of other regions, such as the lower back. Although this holds important implications for rehabilitation, no studies have examined corticomotor adaptations following short-term motor training in the lower back.
The aims of this study were to (a) determine whether a short-term lumbopelvic tilt visuomotor task induced reorganization of the corticomotor representations of lower back muscles, (b) quantify the variability of corticomotor responses to motor training, and (c) determine whether any improvements in task performance were correlated with corticomotor reorganization. Participants were allocated randomly to perform a lumbopelvic tilt motor training task (n = 15) or a finger abduction control task involving no lumbopelvic movement (n = 15). Transcranial magnetic stimulation was used to map corticomotor representations of the lumbar erector spinae before, during, and after repeated performance of the allocated task.
No relationship between corticomotor reorganization and improved task performance was identified. Substantial variability was observed in terms of corticomotor responses to motor training, with approximately 50% of participants showing no corticomotor reorganization despite significant improvements in task performance.
These findings suggest that short-term improvements in lower back visuomotor task performance may be driven by changes in remote subcortical and/or spinal networks rather than adaptations in corticomotor pathways. However, further research using tasks of varying complexities and durations is required to confirm this hypothesis.
越来越多的证据表明，运动技能训练与大脑初级运动皮层的结构和功能重组有关。然而，之前的研究主要集中在上肢，目前尚不清楚在对背部等其他区域进行训练后是否会发生类似的重组。尽管这对康复具有重要意义，但目前还没有研究探讨过短期下背部运动训练后皮质运动的适应性变化。
本研究的目的是：（a）确定短期腰骶倾斜视觉运动任务是否会引起下背部肌肉皮质运动代表区的重组；（b）量化皮质运动反应在运动训练中的可变性；（c）确定任务表现的任何改善是否与皮质运动重组相关。参与者被随机分配执行腰骶倾斜运动训练任务（n=15）或不涉及腰骶运动的手指外展控制任务（n=15）。使用经颅磁刺激在下背部竖脊肌的皮质运动代表区进行测量，在分配任务之前、期间和之后进行测量。
未发现皮质运动重组与任务表现改善之间存在关系。皮质运动反应在运动训练中存在很大的可变性，大约 50%的参与者尽管任务表现有显著改善，但没有皮质运动重组。
这些发现表明，下背部视觉运动任务表现的短期改善可能是由远程皮质下和/或脊髓网络的变化而不是皮质运动通路的适应性变化驱动的。然而，需要使用具有不同复杂性和持续时间的任务进一步研究来验证这一假设。
