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

Brooks

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


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Abstract

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.

Acceptance Date Feb 18, 2012
Publication Date Mar 7, 2012
Publicly Available Date Mar 28, 2024
Journal Neuropsychologia
Print ISSN 0028-3932
Publisher Elsevier
Pages 1393 - 1407
DOI https://doi.org/10.1016/j.neuropsychologia.2012.02.024
Keywords Figure-ground organisation; Segmentation; Perceptual organisation; Context; Gestalt; Developmental visual agnosia; Grouping; Integration
Publisher URL https://doi.org/10.1016/j.neuropsychologia.2012.02.024

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