Fujii N, Mushiake H, Tanji J
Department of Physiology, Tohoku University School of Medicine, Sendai, 980, Japan.
Proc Natl Acad Sci U S A. 1998 Sep 29;95(20):12034-7. doi: 10.1073/pnas.95.20.12034.
We explored the ventral part of the premotor cortex (PMV) with intracortical microstimulation (ICMS) while monkeys performed a visual fixation task, to see whether the PMV is involved in oculomotor control. ICMS evoked saccades from a small-restricted region in the PMV, without evoking movements in the limbs, neck, or body. We found the saccade-evoking site in the PMV in a total of three hemispheres in two monkeys. Quantitative analysis of the effects of eye position on saccades evoked by microstimulation of the PMV characterized the evoked saccades as goal directed. The nature of the saccades evoked in the PMV contrasted with the fixed vector nature of saccades evoked by ICMS of the frontal eye field. We also found that neurons in this restricted area of the PMV were active while the animals were performing a saccade task that required them to make saccades toward targets without arm movements. These data provide evidence for the presence of an oculomotor-specific subregion within the PMV. This subregion and the surrounding skeletomotor-representing regions of the PMV seem to coordinate oculomotor and skeletomotor control in performing goal-directed motor tasks.
在猴子执行视觉注视任务时，我们采用皮层内微刺激（ICMS）对运动前区腹侧部（PMV）进行了探索，以研究PMV是否参与眼球运动控制。ICMS在PMV的一个小的受限区域诱发了扫视，而未诱发四肢、颈部或身体的运动。我们在两只猴子的总共三个半球中发现了PMV中的扫视诱发位点。对眼位对PMV微刺激诱发扫视的影响进行的定量分析表明，诱发的扫视具有目标导向性。PMV中诱发的扫视的性质与额叶眼区ICMS诱发的扫视的固定矢量性质形成对比。我们还发现，在动物执行需要它们在不移动手臂的情况下向目标进行扫视的扫视任务时，PMV这个受限区域内的神经元是活跃的。这些数据为PMV中存在一个眼球运动特异性亚区域提供了证据。这个亚区域以及PMV周围代表骨骼运动的区域似乎在执行目标导向的运动任务时协调眼球运动和骨骼运动控制。
