Scott S H, Sergio L E, Kalaska J F
Centre de Recherche en Sciences Neurologiques, Université de Montréal, Montreal, Quebec H3C 3J7, Canada.
J Neurophysiol. 1997 Nov;78(5):2413-26. doi: 10.1152/jn.1997.78.5.2413.
Reaching movements with similar hand paths but different arm orientations. II. Activity of individual cells in dorsal premotor cortex and parietal area 5. J. Neurophysiol. 78: 2413-2426, 1997. Neuronal activity in primary motor cortex (MI) is altered when monkeys make reaching movements along similar handpaths at shoulder level with two different arm orientations, either in the natural orientation with the elbow positioned below the level of the shoulder and hand or in an abducted orientation with the elbow abducted nearly to shoulder level. The present study examines to what degree two other cortical areas, the dorsal premotor (PMd) and parietal area 5, also show modulation of cell activity related to arm geometry during reaching. The activity of most (89%) of the 207 cells in PMd recorded while monkeys made reaching movements showed a statistically significant change in activity between orientations [analysis of variation (ANOVA), P < 0.01]. A common effect of arm orientation on cell activity was a change in the overall level of discharge either before, during, and/or after movement (67%, ANOVA, task main effect, P < 0.01). Many cells (76%) showed a statistical change in their response to movement direction (ANOVA, task x direction interaction term, P < 0.01), including changes in dynamic range and changes in the preferred direction of cells that were directionally tuned in both arm orientations. Overall, these effects were similar qualitatively but not as strong quantitatively as those observed in MI. A sample of cells was recorded in area 5 of one monkey. Most (95%) of the 79 area 5 cells showed a change in activity when reaching movements were performed using different arm orientations (ANOVA, P < 0.01). As in PMd and MI, many area 5 cells (56, 71%) showed changes in their tonic discharge before, during, and/or after movement, and 70 cells (89%) showed changes in their response to movement direction (ANOVA, task x direction interaction term, P < 0.01). The observed changes in neuronal activity related to posture and movement in MI, PMd and area 5 demonstrate that single-cell activity in these cortical areas is not simply related to the spatial attributes of hand trajectory but is also strongly influenced by attributes of movement related to arm geometry.
手部路径相似但手臂方位不同时的伸展动作。II. 背侧运动前皮层和顶叶5区单个细胞的活动。《神经生理学杂志》78: 2413 - 2426, 1997年。当猴子以两种不同的手臂方位在肩部水平沿相似的手部路径进行伸展动作时，初级运动皮层（MI）中的神经元活动会发生改变，这两种方位一种是自然方位，即肘部位于肩部和手部水平以下，另一种是外展方位，即肘部外展至接近肩部水平。本研究考察了另外两个皮层区域，即背侧运动前区（PMd）和顶叶5区，在伸展过程中与手臂几何形状相关的细胞活动调制程度。在猴子进行伸展动作时记录的PMd区207个细胞中，大多数（89%）细胞的活动在不同方位之间显示出具有统计学意义的变化[方差分析（ANOVA），P < 0.01]。手臂方位对细胞活动的一个常见影响是在运动前、运动中和/或运动后放电总体水平的变化（67%，ANOVA，任务主效应，P < 0.01）。许多细胞（76%）在对运动方向的反应上显示出统计学变化（ANOVA，任务×方向交互项，P < 0.01），包括动态范围的变化以及在两种手臂方位中都具有方向调谐的细胞的偏好方向的变化。总体而言，这些效应在定性上相似，但在定量上不如在MI中观察到的那么强烈。在一只猴子的5区记录了一组细胞样本。79个5区细胞中的大多数（95%）在使用不同手臂方位进行伸展动作时显示出活动变化（ANOVA，P < 0.01）。与PMd和MI中一样，许多5区细胞（56, 71%）在运动前、运动中和/或运动后其紧张性放电发生了变化，70个细胞（89%）在对运动方向的反应上发生了变化（ANOVA，任务×方向交互项，P < 0.01）。在MI、PMd和5区观察到的与姿势和运动相关的神经元活动变化表明，这些皮层区域中的单细胞活动不仅与手部轨迹的空间属性简单相关，还受到与手臂几何形状相关的运动属性的强烈影响。
