Romo R, Scarnati E, Schultz W
Institut de Physiologie, Université de Fribourg, Switzerland.
Exp Brain Res. 1992;91(3):385-95. doi: 10.1007/BF00227835.
In order to more comprehensively assess the role of the basal ganglia in the internal generation of movements, we studied the activity of neurons in the head of the caudate and in the rostral putamen in relation to the execution of movements. Monkeys performed self-initiated and stimulus-triggered arm reaching movements in separate blocks of trials. With stimulus-triggered movements, 217 striatal neurons increased their activity after the trigger stimulus (127 in caudate, 90 in putamen). Of these, 68 neurons showed time-locked responses to the trigger stimulus, with a median latency of 60 ms, that were independent of visual or auditory stimulus modalities. Three quarters of responses were conditional on a movement being performed. These responses may participate in neuronal processes through which the reception of a stimulus is translated into the execution of a behavioral reaction. Further, 44 neurons increased their activity before the earliest muscle activity without being clearly time-locked to the stimulus (148-324 ms before movement onset), 55 neurons were activated later before the movement, and 50 neurons were activated after movement onset. With self-initiated movements, 106 striatal neurons showed movement-related activity beginning up to 460 ms before movement onset (52 in caudate, 54 in putamen). Comparisons between the two types of movement were made on 53 neurons with premovement activity beginning more than 500 ms before self-initiated movements. Only one fifth of them also showed movement-related activity with stimulus-triggered movements, including trigger responses. Comparisons among 39 neurons with movement-related activity during self-initiated arm movements showed that about half of them also showed movement-related activity with stimulus-triggered movements. These data demonstrate a considerably segregated population of striatal neurons engaged in the internal generation of movements, whereas processes underlying the execution of movements appear to involve overlapping neuronal populations.
为了更全面地评估基底神经节在运动内在生成中的作用，我们研究了尾状核头部和壳核前部神经元的活动与运动执行的关系。猴子在不同的试验组中进行自发和刺激触发的手臂伸展运动。在刺激触发的运动中，217个纹状体神经元在触发刺激后活动增加（尾状核127个，壳核90个）。其中，68个神经元对触发刺激表现出与时间锁定的反应，中位潜伏期为60毫秒，且与视觉或听觉刺激模式无关。四分之三的反应取决于是否执行运动。这些反应可能参与了神经元过程，通过这些过程，刺激的接收被转化为行为反应的执行。此外，44个神经元在最早的肌肉活动之前活动增加，但与刺激没有明显的时间锁定（运动开始前148 - 324毫秒），55个神经元在运动前较晚被激活，50个神经元在运动开始后被激活。在自发运动中，106个纹状体神经元在运动开始前长达460毫秒就表现出与运动相关的活动（尾状核52个，壳核54个）。对53个在自发运动前500毫秒以上开始有运动前活动的神经元进行了两种运动类型之间的比较。其中只有五分之一的神经元在刺激触发的运动中也表现出与运动相关的活动，包括触发反应。对39个在自发手臂运动期间有运动相关活动的神经元进行比较表明，其中约一半在刺激触发的运动中也表现出与运动相关的活动。这些数据表明，参与运动内在生成的纹状体神经元群体有相当大的分离，而运动执行的潜在过程似乎涉及重叠的神经元群体。
