Goldberg M E, Segraves M A
Laboratory of Sensorimotor Research, National Eye Institute, Bethesda, MD 20892.
Rev Oculomot Res. 1989;3:283-313.
The saccadic system uses a muscular apparatus and motor programs that evolved long before the cerebral cortex assumed the dominant role in the generation of behavior that it occupies in the primate. The cortical role in eye movements therefore is to contribute aspects of sophisticated processing to the basic apparatus for rapid eye movements. Thus visual cortex is necessary for the integration of visual motion information into the saccadic system, because the superior colliculus in the primate cannot do adequate motion processing. Similarly, frontal cortex is necessary for performing saccades to remembered stimulus positions, whereas visually driven saccades can be performed by the colliculus alone. To generate saccade-related information, the cortex has activity that reflects all levels of processing, from the registration of the stimulus and the selection of a stimulus for a saccade, to the elaboration of the motor command for the saccade. Presumably the cortex also contains the decision mechanism, whereby a primate decides to make a saccade to a certain stimulus. How, and where that decision is made, or even if the decision occurs at a single place, is totally unknown.
扫视系统使用一种肌肉装置和运动程序，这些在大脑皮层在灵长类动物行为产生中占据主导地位之前很久就已经进化出来了。因此，大脑皮层在眼球运动中的作用是为快速眼球运动的基本装置贡献复杂处理的各个方面。因此，视觉皮层对于将视觉运动信息整合到扫视系统中是必要的，因为灵长类动物的上丘无法进行充分的运动处理。同样，额叶皮层对于向记忆中的刺激位置进行扫视是必要的，而视觉驱动的扫视可以仅由上丘完成。为了生成与扫视相关的信息，皮层具有反映从刺激的登记和扫视刺激的选择到扫视运动指令的细化等所有处理水平的活动。据推测，皮层还包含决策机制，灵长类动物由此决定向某个刺激进行扫视。这个决策是如何做出的、在哪里做出的，甚至是否在一个单一的位置做出，完全未知。
