Stasheff S F, Barton J J
Department of Neurology, Beth Israel Deaconess Medical Center and Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
Ophthalmol Clin North Am. 2001 Mar;14(1):217-42, x.
Lesions of extrastriate cortex cause selective defects in visual function. Damage to portions of the "ventral stream" in medial and inferior occipitotemporal cortex lead to impaired perception of color or various specific visual object recognition defects, such as prospagnosia, the inability to recognize familiar faces, and alexia, the inability to read. The latter must be distinguished from a variety of other reading defects related to primary visual, attentional, linguistic, or ocular motor impairments. Damage to the "dorsal stream" in lateral occipito-temporo-parietal regions impairs visuospatial capabilities, leading to akinetopsia (impaired motion perception) or Balint's syndrome, a loosely bound triad of simultanagnosia, optic ataxia, and ocular motor apraxia. Topographagnosia can occur with ventral or dorsoal lesions for different reasons. Considerable evidence has accumulated showing that residual vision or even "blindsight," which is visual perception in the absence of awareness, can persist after lesion of striate cortex in some patients.
纹外皮层病变会导致视觉功能出现选择性缺陷。枕颞叶内侧和下部“腹侧流”部分受损会导致颜色感知受损或各种特定的视觉物体识别缺陷，如面容失认症（无法识别熟悉的面孔）和失读症（无法阅读）。后者必须与其他各种与初级视觉、注意力、语言或眼球运动障碍相关的阅读缺陷区分开来。枕颞顶叶外侧区域的“背侧流”受损会损害视觉空间能力，导致运动失认症（运动感知受损）或巴林特综合征，这是一种由同时失认症、视觉性共济失调和眼球运动失用症组成的松散三联征。不同原因导致的腹侧或背侧病变都可能出现地形定向障碍。大量证据表明，在一些患者中，纹状皮层受损后，残余视力甚至“盲视”（无意识的视觉感知）可能会持续存在。
