Kazennikov O V, Solopova I A, Talis V L, Ioffe M E
Zh Vyssh Nerv Deiat Im I P Pavlova. 2006 Sep-Oct;56(5):603-10.
The role of the motor cortex was investigated during learning unusual postural adjustment. Healthy subjects held their right (postural) forearm in a horizontal position while supporting a 1-kG load via an electromagnet. The postural forearm position was perturbed by the load release triggered by other elbow voluntary movement. Repetition of the imposed unloading test resulted in a progressive reduction of the maximal forearm rotation, accompanied by the anticipatory decrease in m. biceps brachii activity (learning). Control situation consisted of the voluntary forearm loading. Using the transcranial magnetic stimulation we examined changes in the motor evoked potential of the m. biceps brahii at the beginning and at the end of learning. The evoked potential amplitude did not significantly change in process of the decrease of m. biceps brachii activity. At the end of learning, motor evoked potential / baseline electromyogram ratio increased as compared to the beginning of learning and to the control situation. The results highlight the fundamental role of the motor cortex in suppression of synergies which interfere with formation of a new coordination during motor learning.
在学习异常姿势调整过程中对运动皮层的作用进行了研究。健康受试者将其右侧（姿势）前臂保持在水平位置，同时通过电磁铁支撑1千克的负荷。姿势性前臂位置会因其他肘部自主运动触发的负荷释放而受到干扰。重复进行施加的卸载测试导致最大前臂旋转逐渐减少，同时肱二头肌活动出现预期性降低（学习过程）。对照情况为前臂的自主加载。我们使用经颅磁刺激检查了学习开始时和结束时肱二头肌运动诱发电位的变化。在肱二头肌活动减少的过程中，诱发电位幅度没有显著变化。在学习结束时，与学习开始时和对照情况相比，运动诱发电位/基线肌电图比值增加。结果突出了运动皮层在抑制协同作用方面的基本作用，这些协同作用会干扰运动学习过程中新协调的形成。
