Assad J A, Maunsell J H
Division of Neuroscience S-603, Baylor College of Medicine, Houston, Texas 77030.
Nature. 1995 Feb 9;373(6514):518-21. doi: 10.1038/373518a0.
For many types of behaviours, it is necessary to monitor the position or movement of objects that are temporarily occluded. The primate posterior parietal cortex contains neurons that are active during visual guidance tasks: in some cases, even if the visual target disappears transiently. It has been proposed that activity of this sort could be related to current or planned eye movements, but it might also provide a more generalized abstract representation of the spatial disposition of targets, even when they are not visible. We have recorded from monkey posterior parietal cortex while the animal viewed a visual stimulus that disappeared, and then, depending on experimental context, could be inferred to be either moving or stationary. During this temporary absence of the stimulus, about half of the neurons were found to be significantly more active on those trials in which the stimulus could be presumed to be moving rather than stationary. The activity was thus present in the absence of either sensory input or motor output, suggesting that it may indeed constitute a generalized representation of target motion.
对于许多类型的行为而言，监测暂时被遮挡物体的位置或运动是很有必要的。灵长类动物的顶叶后皮质包含在视觉引导任务期间活跃的神经元：在某些情况下，即使视觉目标短暂消失也是如此。有人提出，这类活动可能与当前或计划中的眼球运动有关，但它也可能提供目标空间布局的更广义抽象表征，即使目标不可见时也是如此。我们在猴子观看消失的视觉刺激时记录了其顶叶后皮质的活动，然后根据实验情境，可以推断该刺激是移动的还是静止的。在刺激暂时消失期间，我们发现约一半的神经元在刺激被推测为移动而非静止的试验中显著更活跃。因此，在没有感觉输入或运动输出的情况下仍存在这种活动，这表明它可能确实构成了目标运动的广义表征。
