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

NEUROPSYCHOLOGIA

卷:50

Article

Brooks, Joseph L.¹  Gilaie-Dotan, Sharon^1,2  Rees, Geraint^1,2  Bentin, Shlomo^3,4  Driver, Jon^1,2 

[1] UCL, UCL Inst Cognit Neurosci, London WC1N 3AR, England

[2] UCL, Wellcome Trust Ctr Neuroimaging, London WC1N 3BG, England

[3] Hebrew Univ Jerusalem, Ctr Neural Computat, IL-91905 Jerusalem, Israel

[4] Hebrew Univ Jerusalem, Dept Psychol, IL-91905 Jerusalem, Israel

关键词: Figure-ground organization;    Segmentation;    Perceptual organization;    Context;    Gestalt;    Developmental visual agnosia;    Grouping;    Integration;   

DOI  :  10.1016/j.neuropsychologia.2012.02.024

来源: Elsevier

【 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. (C) 2012 Elsevier Ltd. All rights reserved.

【 授权许可】

Free