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

Autor: Sharon Gilaie-Dotan, Shlomo Bentin, Geraint Rees, Joseph L. Brooks, Jon Driver
Rok vydání: 2012
Předmět:
Male
Visual perception
genetic structures
Cognitive Neuroscience
Integration
BF
Experimental and Cognitive Psychology
Stimulus (physiology)
Brain mapping
Article
Perceptual organization
Functional Laterality
050105 experimental psychology
Developmental psychology
Association
Gestalt
Young Adult
03 medical and health sciences
Behavioral Neuroscience
Segmentation
0302 clinical medicine
Functional neuroimaging
Grouping
Image Processing
Computer-Assisted
Psychophysics
medicine
Humans
0501 psychology and cognitive sciences
Developmental visual agnosia
Visual agnosia
Brain Mapping
Figure-ground organization
05 social sciences
Context
Figure–ground
Magnetic Resonance Imaging
Frontal Lobe
Semantics
Oxygen
Pattern Recognition
Visual
Agnosia
medicine.symptom
Psychology
Photic Stimulation
030217 neurology & neurosurgery
Cognitive psychology
Zdroj: Neuropsychologia
ISSN: 0028-3932
DOI: 10.1016/j.neuropsychologia.2012.02.024
Popis: Highlights ► We tested a developmental agnosic patient, LG. ► LG shows preserved local but impaired contextual influences on figure-ground. ► LG shows impaired familiarity influences on figure-ground. ► Visual areas V2/V3 play a role in figure-ground context and familiarity effects. ► Local, contextual, and familiarity figure-ground influences are dissociable.
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.
Databáze: OpenAIRE
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