Abnormal processing of visual motion In dyslexia revealed by functional brain imaging
Abnormal processing of visual motion In dyslexia revealed by functional brain imaging
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DOI：
10.1038/382066a0
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发表时间：
1996-07-04
期刊：
影响因子：
64.8
通讯作者：
Zeffiro, TA
中科院分区：
文献类型：
--
作者：
Eden, GF;VanMeter, JW;Zeffiro, TA
人们普遍认为，诵读困难者在阅读和语音意识方面存在缺陷（1，2），但越来越多的证据表明，他们也表现出视觉处理异常，可能仅限于视觉系统的特定部分（3，4）。在灵长类动物的视觉通路中，来自外侧膝状体核的小细胞或大细胞层的输入在向专门处理颜色和形状与运动的纹外皮质区的投射中保持部分分离（5-10）。在阅读障碍的研究中，心理物理（3）和解剖学（4）证据表明大细胞视觉子系统中存在异常。为了研究阅读障碍的病理生理学，我们用功能磁共振成像（fMRI）研究了正常人和阅读障碍者的视觉运动加工。在所有阅读障碍者中，运动刺激的呈现都不能在V5/MT区产生相同的任务相关功能激活（大细胞视觉子系统的一部分），相反，静态模式的呈现导致两组V1/V2和纹外皮层的激活相等。尽管以前的研究强调语言缺陷，但我们的数据显示了阅读障碍患者皮层视觉系统区域功能组织的差异。
IT is widely accepted that dyslexics have deficits in reading and phonological awareness(1,2), but there is increasing evidence that they also exhibit visual processing abnormalities that may be confined to particular portions of the visual system(3,4). In primate visual pathways, inputs from parvocellular or magnocellular layers of the lateral geniculate nucleus remain partly segregated in projections to extrastriate cortical areas specialized for processing colour and form versus motion(5-10), In studies of dyslexia, psychophysical(3) and anatomical(4) evidence indicate an anomaly in the magnocellular visual subsystem, To investigate the pathophysiology of dyslexia, we used functional magnetic resonance imaging (fMRI) to study visual motion processing in normal and dyslexic men, In all dyslexics, presentation of moving stimuli failed to produce the same task-related functional activation in area V5/MT (part of the magnocellular visual subsystem) observed in controls, In contrast, presentation of stationary patterns resulted in equivalent activations in V1/V2 and extrastriate cortex in both groups, Although previous studies have emphasized language deficits, our data reveal differences in the regional functional organization of the cortical visual system in dyslexia.