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Contour extracting networks in early extrastriate cortex

Dumoulin, SO and Hess, RF and May, KA and Harvey, BM and Rokers, B and Barendregt, M (2014) 'Contour extracting networks in early extrastriate cortex.' Journal of vision, 14 (5). p. 18. ISSN 1534-7362

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Neurons in the visual cortex process a local region of visual space, but in order to adequately analyze natural images, neurons need to interact. The notion of an ?association field? proposes that neurons interact to extract extended contours. Here, we identify the site and properties of contour integration mechanisms. We used functional magnetic resonance imaging (fMRI) and population receptive field (pRF) analyses. We devised pRF mapping stimuli consisting of contours. We isolated the contribution of contour integration mechanisms to the pRF by manipulating the contour content. This stimulus manipulation led to systematic changes in pRF size. Whereas a bank of Gabor filters quantitatively explains pRF size changes in V1, only V2/V3 pRF sizes match the predictions of the association field. pRF size changes in later visual field maps, hV4, LO-1, and LO-2 do not follow either prediction and are probably driven by distinct classical receptive field properties or other extraclassical integration mechanisms. These pRF changes do not follow conventional fMRI signal strength measures. Therefore, analyses of pRF changes provide a novel computational neuroimaging approach to investigating neural interactions. We interpreted these results as evidence for neural interactions along co-oriented, cocircular receptive fields in the early extrastriate visual cortex (V2/V3), consistent with the notion of a contour association field.

Item Type: Article
Uncontrolled Keywords: Visual Cortex; Neurons; Humans; Magnetic Resonance Imaging; Form Perception; Adult; Female; Male; Young Adult
Subjects: R Medicine > RE Ophthalmology
Divisions: Faculty of Science and Health
Faculty of Science and Health > Psychology, Department of
SWORD Depositor: Elements
Depositing User: Elements
Date Deposited: 15 Nov 2016 13:24
Last Modified: 06 Jan 2022 13:31

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