Ro T, Rorden C, Driver J, Rafal R
Department of Psychology, Rice University, Houston, TX 77005-1892, USA.
J Cogn Neurosci. 2001 Oct 1;13(7):920-9. doi: 10.1162/089892901753165836.
We examined the effects of chronic unilateral lesions to either the inferior parietal lobe, or to the dorsolateral prefrontal cortex including the frontal eye fields (FEFs), upon human visual perception and saccades in temporal-order-judgment (TOJ) tasks. Two visual events were presented on each trial, one in each hemifield at various stimulus onset asynchronies (SOAs). In the saccade task, patients moved their eyes to whichever stimulus attracted gaze first. In the perceptual-manual task, they pressed a button to indicate which stimulus was perceived first. Frontal patients showed appropriate TOJs for visual targets in both tasks. Parietal patients showed appropriate TOJs in the perceptual-manual but not the saccade task; their saccades tended to be ipsilesional unless the contralesional target led substantially. This reveals a bias in saccade choice after parietal damage that cannot be attributed to deficient visual perception. These results challenge previous claims that only anterior lesions produce motoric spatial biases in humans. However, they are in accord with recent neurophysiological evidence for parietal involvement in saccade generation, and also with suggestions that visuomotor transformations in the parietal lobe serving direct spatial motor responses can dissociate from conscious perception as indicated by indirect arbitrary responses.
我们研究了慢性单侧损伤对下顶叶或包括额叶眼区（FEF）在内的背外侧前额叶皮层的影响，这些损伤会影响人类在时间顺序判断（TOJ）任务中的视觉感知和扫视。每次试验呈现两个视觉事件，在每个半视野中各呈现一个，二者具有不同的刺激起始异步性（SOA）。在扫视任务中，患者将眼睛移向首先吸引注视的刺激物。在感知手动任务中，他们按下按钮以指示首先感知到的刺激物。额叶患者在两项任务中对视觉目标都表现出适当的时间顺序判断。顶叶患者在感知手动任务中表现出适当的时间顺序判断，但在扫视任务中则不然；除非对侧目标明显领先，否则他们的扫视往往偏向病侧。这揭示了顶叶损伤后扫视选择的偏差，这种偏差不能归因于视觉感知缺陷。这些结果挑战了先前的说法，即只有前部损伤才会在人类中产生运动性空间偏差。然而，它们与最近关于顶叶参与扫视产生的神经生理学证据一致，也与以下观点一致，即顶叶中服务于直接空间运动反应的视觉运动转换可以与有意识感知分离，如间接任意反应所示。
