Global integration of local color differences in transparency perception: An fMRI study.Report as inadecuate




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* Corresponding author 1 Neuroimagerie Fonctionnelle et Metabolique 2 Cerveau et vision

Abstract : In normal viewing, the visual system effortlessly assigns approximately constant attributes of color and shape to perceived objects. A fundamental component of this process is the compensation for illuminant variations and intervening media to recover reflectance properties of natural surfaces. We exploited the phenomenon of transparency perception to explore the cortical regions implicated in such processes, using fMRI. By manipulating the coherence of local color differences around a region in an image, we interfered with their global perceptual integration and thereby modified whether the region appeared transparent or not. We found the major cortical activation due to global integration of local color differences to be in the anterior part of the parahippocampal gyrus. Regions differentially activated by chromatic versus achromatic geometric patterns showed no significant differential response related to the coherence-incoherence of local color differences. The results link the integration of local color differences in the extraction of a transparent layer with sites activated by object-related properties of an image.

Keywords : Transparency Color Vision fMRI Human vision





Author: Michel Dojat - Loÿs Piettre - Chantal Delon-Martin - Mathilde Pachot-Clouard - Christoph Segebarth - Kenneth Knoblauch -

Source: https://hal.archives-ouvertes.fr/



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