Yahagi S, Kasai T
Department of Sports Sciences, Hiroshima Shudo University, Japan.
Electroencephalogr Clin Neurophysiol. 1998 Oct;109(5):409-17. doi: 10.1016/s0924-980x(98)00041-1.
We investigated changes in motor evoked potentials (MEPs) to explain why mental practice can improve motor performance.
MEPs were recorded from right and left first dorsal interosseous (FDI) muscles of 9 normal, right-handed subjects during different motor images of index finger movement: (1) rest, (2) flexion, (3) abduction, (4) extension. A paired t test was used to compare differences of stimulus intensities and MEP amplitudes among conditions.
MEP amplitudes significantly increased in both FDI muscles during motor images of flexion and abduction but not of extension. Moreover, MEP amplitudes were larger in flexion than in abduction. These differences were proportional to the amount of real EMG discharge of FDI muscle in the selected direction of index finger movement. With regard to right-left differences, MEP amplitudes in the right FDI muscle were larger than those in the left.
The primary motor cortex plays a role in the mental representation of motor acts. Furthermore, the amount of corticomotoneuronal cell activity is affected by the different motor images utilizing the same muscle. Right-left difference of MEP amplitude supports the view of left-hemisphere dominance for motor programming as an aspect of normal brain function among right-handers.
我们研究了运动诱发电位（MEP）的变化，以解释为什么心理练习可以改善运动表现。
在9名正常右利手受试者的右手和左手第一背侧骨间肌（FDI）记录MEP，记录时受试者进行不同的食指运动想象：（1）休息，（2）屈曲，（3）外展，（4）伸展。采用配对t检验比较不同条件下刺激强度和MEP波幅的差异。
在屈曲和外展运动想象期间，双侧FDI肌的MEP波幅均显著增加，但伸展运动想象时未增加。此外，屈曲时的MEP波幅大于外展时。这些差异与食指运动选定方向上FDI肌实际肌电图放电量成比例。关于左右差异，右侧FDI肌的MEP波幅大于左侧。
初级运动皮层在运动行为的心理表征中起作用。此外，利用同一肌肉的不同运动想象会影响皮质脊髓运动神经元细胞的活动量。MEP波幅的左右差异支持了在右利手人群中，作为正常脑功能的一个方面，左半球在运动编程中占主导地位的观点。
