Preserved local but disrupted contextual figure-ground influences in an individual with abnormal function of intermediate visual areas

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• 作者：Joseph L. Brooks^a ; ^{joseph.brooks@ucl.ac.uk} ; Sharon Gilaie-Dotan^a ; ^b ; Geraint Rees^a ; ^b ; Shlomo Bentin^c ; Jon Driver^a ; ^b ; ¹
• 关键词：Figure-ground organization ; Segmentation ; Perceptual organization ; Context ; Gestalt ; Developmental visual agnosia ; Grouping ; Integration
• 刊名：Neuropsychologia
• 出版年：2012
• 期刊代码：205_00283932
• 类别：med
• 出版时间：June, 2012
• 卷：50
• 期：7
• 页码：1393-1407
• 文件大小：926 K

摘要

Visual perception depends not only on local stimulus features but also on their relationship to the surrounding stimulus context, as evident in both local and contextual influences on figure-ground segmentation. Intermediate visual areas may play a role in such contextual influences, as we tested here by examining LG, a rare case of developmental visual agnosia. LG has no evident abnormality of brain structure and functional neuroimaging showed relatively normal V1 function, but his intermediate visual areas (V2/V3) function abnormally. We found that contextual influences on figure-ground organization were selectively disrupted in LG, while local sources of figure-ground influences were preserved. Effects of object knowledge and familiarity on figure-ground organization were also significantly diminished. Our results suggest that the mechanisms mediating contextual and familiarity influences on figure-ground organization are dissociable from those mediating local influences on figure-ground assignment. The disruption of contextual processing in intermediate visual areas may play a role in the substantial object recognition difficulties experienced by LG.