Department of Neurology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
Cereb Cortex. 2010 Jun;20(6):1323-31. doi: 10.1093/cercor/bhp196. Epub 2009 Nov 11.
The preparation of a voluntary unimanual action requires sequential processing in bihemispheric motor areas. In both animals and humans, activity in the dorsal premotor cortex (PMd) ipsilateral to the moving hand has been demonstrated to precede ipsilateral primary motor cortex (M1) activity. We investigated with double-pulse transcranial magnetic stimulation how right-hemispheric motor areas (rM1, rPMd) modulate left M1 (lM1) during the preparatory period of a finger movement with the dominant right hand. We tested the hypothesis that the influence of higher order motor areas such as rPMd on lM1 (rPMd-lM1) precedes interhemispheric interactions between homologue primary motor areas (rM1-lM1). rPMd-lM1 showed modulation in the early and late phase of movement preparation, whereas the intrinsic state of inhibition between rM1-lM1 was only modulated in the late phase. The present results complement existing hierarchical models of cortical movement control by demonstrating temporospatially distinct involvement of interhemispheric interactions from PMd and M1 during movement preparation.
自愿单 mano 动作的准备需要在大脑两半球的运动区域中进行顺序处理。在动物和人类中，已证明与移动手同侧的背侧运动前皮质 (PMd) 的活动先于同侧初级运动皮质 (M1) 的活动。我们通过双脉冲经颅磁刺激研究了右半球运动区域 (rM1、rPMd) 在使用占主导地位的右手进行手指运动的预备期间如何调节左侧 M1 (lM1)。我们检验了这样一个假设，即较高阶运动区域（如 rPMd）对 lM1 的影响（rPMd-lM1）先于同源初级运动区域（rM1-lM1）之间的半球间相互作用。rPMd-lM1 在运动准备的早期和晚期阶段表现出调制，而 rM1-lM1 之间的内在抑制状态仅在晚期阶段被调制。本研究结果通过证明在运动准备期间 PMd 和 M1 的半球间相互作用具有时间和空间上的不同参与，补充了现有的皮质运动控制层次模型。
