Experimental Psychology, Helmholtz Institute, Utrecht University, Utrecht, The Netherlands.
Brain Cogn. 2013 Jul;82(2):192-200. doi: 10.1016/j.bandc.2013.04.007. Epub 2013 May 11.
The frontal oculomotor cortex is known to play an important role in oculomotor selection. The aim of the current study was to examine whether previously observed findings concerning the role of the frontal oculomotor cortex in the speed of saccade initiation and oculomotor inhibition might be related to a common underlying role of these areas in oculomotor selection. To this end, six patients with lesions to the frontal oculomotor cortex performed a double stimulus paradigm in which two elements were presented simultaneously in close proximity. Patients performed a block in which no specific task instruction was given and a block in which an instruction was provided about which of the two elements was the target. The rationale behind this manipulation was that the introduction of a specific task instruction would require a stronger involvement of top-down factors. In contrast to the block without a specific task instruction, saccade latencies to the contralesional visual field were longer than the ipsilesional visual field when a task instruction was given. This effect was strongest for saccades that landed away from the target and the distractor, reflecting trials in which strong oculomotor inhibition was applied. The observed deficits can be explained in terms of a slowing of the inhibitory signals associated with the rejection of a distractor. Given the known role of the Frontal Eye Fields and the location of the lesions, we attribute these findings to the Frontal Eye Fields, revealing their important role in the voluntary control of eye movements.
额眼运动皮层在眼球运动选择中起着重要作用。本研究旨在探讨先前观察到的额眼运动皮层在眼球运动起始速度和眼球运动抑制中的作用是否与这些区域在眼球运动选择中具有共同的潜在作用有关。为此，六名额眼运动皮层损伤的患者在双刺激范式中同时呈现两个元素，它们彼此接近。患者进行了无特定任务指令的块和提供关于两个元素中哪一个是目标的指令的块。这种操作的基本原理是，引入特定的任务指令需要更强的自上而下因素的参与。与无特定任务指令的块相比，当给出任务指令时，对侧视野的眼跳潜伏期长于同侧视野。当目标和干扰物远离时，这种效果最强，反映了应用强烈眼球运动抑制的试验。可以根据与拒绝干扰物相关的抑制信号的减慢来解释观察到的缺陷。鉴于额眼区的已知作用和损伤部位，我们将这些发现归因于额眼区，揭示了它们在眼球运动的自愿控制中的重要作用。
