Matsumoto Amiri, Liang Nan, Ueda Hajime, Irie Keisuke
Cognitive Motor Neuroscience, Human Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
Front Hum Neurosci. 2021 Oct 28;15:703377. doi: 10.3389/fnhum.2021.703377. eCollection 2021.
To investigate whether the changes in the corticospinal excitability contribute to the anticipatory postural adjustments (APAs) in the lower limb muscles when performing the ballistic upper limb movement of the dart throwing. We examined the primary motor cortex (M1) excitability of the lower limb muscles [tibialis anterior (TA) and soleus (SOL) muscles] during the APA phase by using transcranial magnetic stimulation (TMS) in the healthy volunteers. The surface electromyography (EMG) of anterior deltoid, triceps brachii, biceps brachii, TA, and SOL muscles was recorded and the motor evoked potential (MEP) to TMS was recorded in the TA muscle along with the SOL muscle. TMS at the hotspot of the TA muscle was applied at the timings immediately prior to the TA onset. The kinematic parameters including the three-dimensional motion analysis and center of pressure (COP) during the dart throwing were also assessed. The changes in COP and EMG of the TA muscle occurred preceding the dart throwing, which involved a slight elbow flexion followed by an extension. The correlation analysis revealed that the onset of the TA muscle was related to the COP change and the elbow joint flexion. The MEP amplitude in the TA muscle, but not that in the SOL muscle, significantly increased immediately prior to the EMG burst (100, 50, and 0 ms prior to the TA onset). Our findings demonstrate that the corticospinal excitability of the TA muscle increases prior to the ballistic upper limb movement of the dart throwing, suggesting that the corticospinal pathway contributes to the APA in the lower limb in a muscle-specific manner.
为了研究在进行飞镖投掷的上肢快速动作时，皮质脊髓兴奋性的变化是否有助于下肢肌肉的预期姿势调整（APA）。我们在健康志愿者中，通过经颅磁刺激（TMS）检查了APA阶段下肢肌肉[胫前肌（TA）和比目鱼肌（SOL）]的初级运动皮层（M1）兴奋性。记录了三角肌前束、肱三头肌、肱二头肌、TA和SOL肌肉的表面肌电图（EMG），并在TA肌肉以及SOL肌肉中记录了对TMS的运动诱发电位（MEP）。在TA肌肉热点处的TMS在TA开始前立即施加。还评估了飞镖投掷过程中的运动学参数，包括三维运动分析和压力中心（COP）。TA肌肉的COP和EMG变化在飞镖投掷之前就已出现，其中包括轻微的肘部屈曲，随后是伸展。相关性分析表明，TA肌肉的开始与COP变化和肘关节屈曲有关。在EMG爆发前（TA开始前100、50和0毫秒），TA肌肉中的MEP幅度显著增加，而SOL肌肉中的MEP幅度没有显著增加。我们的研究结果表明，在飞镖投掷的上肢快速动作之前，TA肌肉的皮质脊髓兴奋性增加，这表明皮质脊髓通路以肌肉特异性方式对下肢的APA有贡献。
