Riehle A, MacKay W A, Requin J
Cognitive Neuroscience Laboratory, National Center for Scientific Research (CNRS), Marseille, France.
Exp Brain Res. 1994;99(1):56-74. doi: 10.1007/BF00241412.
Movement extent and movement force can be independently controlled in motor performance. Therefore, independent representations of extent and force should exist in the central nervous system (CNS). To test this hypothesis, microelectrode recordings were made in sensorimotor cortex of monkeys trained to perform visually cued wrist flexion movements of two extents, against two levels of frictional resistance. An initial preparatory signal (PS) provided complete, partial or no information about extent and/or force of the movement, which had to be performed in response to a second, response signal (RS). The activity of 511 neurons of the primary motor cortex (MI), the premotor cortex (PM), the postcentral cortex (PC), and the posterior parietal cortex (PA) was recorded in two monkeys. Both reaction time (RT) and neuronal data suggest that there exist independent neuronal mechanisms responsible for the programming of either parameter. On the one hand, partial information about either movement parameter shortened RT when compared with the condition of no prior information. On the other hand, there were, among others, two discrete populations of neurons, one related only to extent, the other only to force. Preparatory changes in activity related to either movement parameter were mainly located in the frontal cortex, especially in the PM. After occurrence of the RS, the percentage of selective changes in activity increased and tended to extend to the parietal cortex. In particular during the movement, force-related changes in activity have been encountered in PA. Furthermore, we conducted trial-by-trial correlation analyses between RT and preparatory neuronal activity for all conditions of prior information. The mean correlation coefficient was significantly higher in the condition of information about movement extent than of information about movement force and it was significantly higher in MI/PM than in PC/PA.
在运动表现中，运动幅度和运动力量能够被独立控制。因此，在中枢神经系统（CNS）中应该存在幅度和力量的独立表征。为了验证这一假设，对经过训练以对抗两种摩擦阻力水平进行两种幅度的视觉提示腕部屈曲运动的猴子的感觉运动皮层进行了微电极记录。一个初始预备信号（PS）提供了关于运动幅度和/或力量的完整、部分或无信息，猴子必须根据第二个反应信号（RS）做出相应动作。在两只猴子中记录了初级运动皮层（MI）、运动前皮层（PM）、中央后皮层（PC）和顶叶后皮层（PA）的511个神经元的活动。反应时间（RT）和神经元数据均表明，存在负责对任一参数进行编程的独立神经元机制。一方面，与无先验信息的情况相比，关于任一运动参数的部分信息缩短了反应时间。另一方面，存在两个离散的神经元群体，一个仅与幅度相关，另一个仅与力量相关。与任一运动参数相关的活动的预备性变化主要位于额叶皮层，尤其是在运动前皮层。反应信号出现后，活动的选择性变化百分比增加，并倾向于扩展到顶叶皮层。特别是在运动过程中，在顶叶后皮层观察到了与力量相关的活动变化。此外，我们对所有先验信息条件下的反应时间和预备神经元活动进行了逐次试验相关性分析。在关于运动幅度的信息条件下，平均相关系数显著高于关于运动力量的信息条件，并且在初级运动皮层/运动前皮层中显著高于在中央后皮层/顶叶后皮层中。
