Slobounov S, Johnston J, Chiang H, Ray W J
Department of Kinesiology, The Pennsylvania State University, 19 Recreation Building, University Park, PA 16802-5702, USA.
Clin Neurophysiol. 2002 Sep;113(9):1444-53. doi: 10.1016/s1388-2457(02)00195-5.
This study examined behavioral indices and motor-related cortical potentials (MRCP) of the enslaving phenomenon (i.e. interdependency of finger movement) during isometric force production tasks using each of the four fingers separately and in combination. We examined MRCP preceding force production and those during the achievement of the desired force (ramp phase) and its maintenance (static phase).
Our experimental design systematically controlled the isometric force output, including both ramp and static phases of force production. We applied time-domain averaging of electroencephalographic single trials in order to extract 3 components of MRCP (Bereitshaftspotential, motor potentials, and motor monitoring potentials) preceding and accompanying force responses.
We report two major findings. First, we found the index finger to be more independent, accurate, and to display the larger MRCP amplitude whereas the ring finger was more dependent, less accurate, and displayed smaller MRCP amplitude. Second, adding the neighboring finger when the ring finger produced the task significantly reduced its dependency on uninvolved fingers and increased the accuracy of both ramp and static phases which was not the case with the index finger. The amplitude of MRCP was increased when the ring finger produced the task in combination as compared to when the ring finger performed the task in isolation. In contrast, the amplitude of MRCP was significantly reduced when the index finger produced the task in combination with other fingers when compared to when the index finger performed the task in isolation.
Overall, the amount of the fingers' dependency on the uninvolved fingers (e.g. amount of enslaving) during isometric force production tasks was inversely related with the amplitude of MRCP indicating the contribution of central mechanisms to the enslaving phenomenon.
本研究在等长力产生任务中，分别单独使用以及组合使用四根手指，考察了奴役现象（即手指运动的相互依赖性）的行为指标和与运动相关的皮层电位（MRCP）。我们考察了力产生之前、达到所需力（斜坡阶段）及其维持（静态阶段）期间的MRCP。
我们的实验设计系统地控制了等长力输出，包括力产生的斜坡和静态阶段。我们应用脑电图单次试验的时域平均法，以提取力反应之前和伴随力反应的MRCP的3个成分（ Bereitschaftspotential、运动电位和运动监测电位）。
我们报告了两个主要发现。首先，我们发现食指更独立、更准确，并且显示出更大的MRCP振幅，而无名指更具依赖性、准确性更低，并且显示出更小的MRCP振幅。其次，当无名指执行任务时添加相邻手指，显著降低了其对未参与手指的依赖性，并提高了斜坡和静态阶段的准确性，而食指则不然。与无名指单独执行任务相比，无名指组合执行任务时MRCP的振幅增加。相反，与食指单独执行任务相比，食指与其他手指组合执行任务时MRCP的振幅显著降低。
总体而言，在等长力产生任务中，手指对未参与手指的依赖程度（例如奴役程度）与MRCP的振幅呈负相关，表明中枢机制对奴役现象的作用。
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