Department of Physical Therapy and Assistive Technology, National Yang-Ming University, Taipei, Taiwan.
Clin Neurophysiol. 2013 Jul;124(7):1353-63. doi: 10.1016/j.clinph.2013.02.001. Epub 2013 Mar 7.
This study aims to investigate the role of the primary motor cortex ipsilateral to the movement (ipsilateral M1) in unilateral motor execution.
Fifteen right-handed healthy subjects underwent functional magnetic resonance imaging (fMRI) and transcranial magnetic stimulation (TMS) experiments. Motor tasks were performed with the right-side limb. Subjects followed visual cues to execute movements in the scanner and independent component analysis (ICA) was applied to analyse the data. Interhemispheric inhibition (IHI), short-interval intracortical inhibition (SICI) and recruitment curves (RCs) of motor-evoked potentials (MEPs) in right M1 were measured by TMS and responses were recorded from the left flexor carpi radialis (FCR) and left anterior deltoid (AD).
Group ICA showed activations of bilateral M1s highly related to motor tasks. Additionally, TMS results showed significant increases of MEP RCs on the left FCR and left AD during right wrist flexion and right shoulder flexion. Prominent decreases of IHI and SICI were also observed under the same conditions.
During unilateral muscle contraction, co-activation of the ipsilateral M1 involves additional processes modulated by intra- and interhemispheric interactions and its size of activations is specifically enhanced on the homotopic representation.
The ipsilateral M1 plays a central role in unilateral motor executions.
本研究旨在探讨运动对侧初级运动皮层（对侧 M1）在单侧运动执行中的作用。
15 名右利手健康受试者接受了功能磁共振成像（fMRI）和经颅磁刺激（TMS）实验。运动任务由右侧肢体完成。受试者根据视觉提示在扫描仪中执行运动，采用独立成分分析（ICA）对数据进行分析。通过 TMS 测量右侧 M1 的 运动诱发电位（MEPs）的 抑制（IHI）、短程 抑制（SICI）和募集曲线（RCs），并从左侧桡侧腕屈肌（FCR）和左侧三角肌前束（AD）记录反应。
组 ICA 显示双侧 M1 的激活与运动任务高度相关。此外，TMS 结果表明，在进行右侧腕关节屈曲和右侧肩关节屈曲时，左侧 FCR 和左侧 AD 上的 MEP RCs 显著增加。在相同条件下，还观察到 IHI 和 SICI 的明显下降。
在单侧肌肉收缩期间，对侧 M1 的共同激活涉及由内和外半球相互作用调节的附加过程，其激活程度在同型代表上得到特异性增强。
对侧 M1 在单侧运动执行中起着核心作用。
