Visual Perception of Contextual Effect and Its Neural Correlates
We investigated contextual effect in the visual perception using fMRI measurements. First, we examined spatiotemporal pattern of response modulation in human V1, V2 and V3/VP during contextual modulation of perceptual contrast using fMRI. Analysis of the spatial distribution of the response modulation indicated that multiple neural processes underlie the contextual effects. A long-range interaction that is selective to relative orientation may contribute predominantly to the suppressive response modulation in V1 and V2. Second, we examined higher-level contextual effect in the visual perception. We investigated the neural mechanisms of meaning generation from visual inputs, including Rorschach inkblots, using fMRI. Significant activity was observed in the prefrontal cortex together with distributed regions in the parietal and occipital cortices. The activated brain regions included the memory system for visual information and the spatial processing in visually guided eye movement in the brain. The results provide a clue to identify the brain regions responsible for the thought disorders and eye movement abnormalities of schizophrenia.
KeywordsNaming Task Primary Visual Cortex Test Region Inferior Temporal Gyrus Passive Viewing
Unable to display preview. Download preview PDF.
- Damasio H (1990) Human brain anatomy in computerized images. Oxford University Press, New YorkGoogle Scholar
- Ejima Y, Takahashi S, Yamamoto H, Fukunaga M, Tanaka C, Ebisu T, Umeda M (2003) Interindividual and interspecies variations of the extrastriate visual cortex. Neuro-Report 14:1579–1583Google Scholar
- Talairach J, Tournoux P (1988) Co-planar stereotaxic atlas of the human brain. Thieme, New YorkGoogle Scholar