Movement Neuroscience Laboratory, Department of Exercise Sciences, The University of Auckland, Auckland, New Zealand; Centre for Brain Research, The University of Auckland, Auckland, New Zealand.
Department of Medicine, The University of Auckland, Auckland, New Zealand; Centre for Brain Research, The University of Auckland, Auckland, New Zealand.
Clin Neurophysiol. 2020 Apr;131(4):791-798. doi: 10.1016/j.clinph.2019.12.410. Epub 2020 Jan 24.
Motor learning is relevant in chronic stroke for acquiring compensatory strategies to motor control deficits. However, the neurophysiological mechanisms underlying motor skill acquisition with the paretic upper limb have received little systematic investigation. The aim of this study was to assess the modulation of corticomotor excitability and intracortical inhibition within ipsilesional primary motor cortex (M1) during motor skill learning.
Ten people at the chronic stage after stroke and twelve healthy controls trained on a sequential visuomotor isometric wrist extension task. Skill was quantified before, immediately after, 24 hours and 7 days post-training. Transcranial magnetic stimulation was used to examine corticomotor excitability and short- and long-interval intracortical inhibition (SICI and LICI) pre- and post-training.
The patient group exhibited successful skill acquisition and retention, although absolute skill level was lower compared with controls. In contrast to controls, patients' ipsilesional corticomotor excitability was not modulated during skill acquisition, which may be attributed to excessive ipsilesional LICI relative to controls. SICI decreased after training for both patient and control groups.
Our findings indicate distinct inhibitory networks within M1 that may be relevant for motor learning after stroke.
These findings have potential clinical relevance for neurorehabilitation adjuvants aimed at augmenting the recovery of motor function.
运动学习在慢性中风中具有相关性，可用于获得对运动控制缺陷的补偿策略。然而，对于使用瘫痪上肢进行运动技能习得的神经生理机制，尚未进行系统的研究。本研究旨在评估偏瘫上肢运动技能习得过程中同侧初级运动皮层（M1）内皮质运动兴奋性和内抑制的调制。
10 名处于中风慢性期的患者和 12 名健康对照者接受了顺序视觉运动等长腕伸展任务的训练。在训练前、训练后即刻、24 小时和 7 天后对技能进行了量化。使用经颅磁刺激（TMS）在训练前后检查皮质运动兴奋性和短程及长程内抑制（SICI 和 LICI）。
患者组表现出成功的技能习得和保持，尽管绝对技能水平低于对照组。与对照组不同，患者在技能习得期间同侧皮质运动兴奋性没有被调节，这可能归因于相对于对照组过度的同侧内抑制。训练后，患者和对照组的 SICI 均降低。
我们的发现表明，M1 内存在不同的抑制性网络，这可能与中风后的运动学习有关。
这些发现对旨在增强运动功能恢复的神经康复辅助剂具有潜在的临床意义。
