Hayashi Shikako, Shimura Kuniyoshi, Kasai Tatsuya
Division of Sports and Health Sciences, Graduate School for International Development and Cooperation, Hiroshima University, 1-5-I Kagamiyama, Higashi-Hiroshima City, Hiroshima, 739-8529 Japan.
Percept Mot Skills. 2005 Oct;101(2):575-86. doi: 10.2466/pms.101.2.575-586.
Excitability changes of human primary motor cortex are assumed to be associated with motor learning processes. To examine motor behavioral and neural mechanisms in these processes, the adaptive motor learning processes of the index finger abduction were investigated using motor evoked potential (MEP) elicited from the first dorsal interosseous and extensor carpi radialis muscles. Practice effects were examined on changes of MEP amplitudes elicited from these muscles during motor imagery. Given general consensus that the MEP amplitude change during motor imagery is a useful parameter reflecting changes in excitability of the human primary motor cortex, the present results, that MEP amplitudes of both muscles increased with repeated practice by the index finger abduction and that magnitudes of MEP amplitudes of both muscles (motor learning curves) were clearly different, suggested that participation of the muscles performing the index finger abduction gradually changed with practice. Short-term plastic changes of human primary motor cortex occur with repetitive practice and such adaptive change in human primary motor cortex is expressed in human voluntary movement that becomes more automatic.
人类初级运动皮层的兴奋性变化被认为与运动学习过程有关。为了研究这些过程中的运动行为和神经机制，利用从第一背侧骨间肌和桡侧腕伸肌引出的运动诱发电位（MEP），对食指外展的适应性运动学习过程进行了研究。在运动想象期间，检查了练习对从这些肌肉引出的MEP振幅变化的影响。鉴于普遍认为运动想象期间MEP振幅变化是反映人类初级运动皮层兴奋性变化的一个有用参数，目前的结果表明，随着食指外展的重复练习，两块肌肉的MEP振幅均增加，且两块肌肉的MEP振幅大小（运动学习曲线）明显不同，这表明随着练习，执行食指外展的肌肉参与情况逐渐发生变化。人类初级运动皮层的短期可塑性变化随着重复练习而发生，并且这种人类初级运动皮层的适应性变化在变得更加自动的人类自主运动中表现出来。
