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Texture segmentation without human V4

Norman, L.J.; Heywood, C.A.; Kentridge, R.W.

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C.A. Heywood


Texture segmentation, or second-order segmentation, is a rapid perceptual process, allowing object and surface boundaries to be effortlessly detected. It is currently unclear whether this is achieved in early cortical areas or whether it necessitates the region referred to as human V4. The present report presents a single case study of patient MS, whose bilateral occipitotemporal damage includes the putative human V4 area, yet whose early visual cortex is spared. As shown in these experiments, MS can accurately locate a target defined by an orientation contrast to its background, even with considerable orientation noise. Importantly, his performance was significantly reduced when the texture edges were masked by black borders (thus preventing edge-based segmentation), indicating that he retains a functional edge-based texture segmentation process. Additionally, when the sign of the orientation contrast was reversed at a temporal frequency of 12.5 Hz, MS could nonetheless detect the contours defined by the orientation contrast despite being unable to judge whether the surfaces either side of the contrast were the same or not. This reveals that MS’s early visual cortex is sufficient for the intact phase-insensitive component of texture segmentation. Human area V4, therefore, is not necessary for texture segmentation.


Norman, L., Heywood, C., & Kentridge, R. (2017). Texture segmentation without human V4. Visual Cognition, 25(1-3), 184-195.

Journal Article Type Article
Acceptance Date Feb 21, 2017
Online Publication Date Mar 20, 2017
Publication Date Mar 20, 2017
Deposit Date Feb 28, 2017
Publicly Available Date Mar 20, 2018
Journal Visual Cognition
Print ISSN 1350-6285
Electronic ISSN 1464-0716
Publisher Taylor and Francis Group
Peer Reviewed Peer Reviewed
Volume 25
Issue 1-3
Pages 184-195


Accepted Journal Article (900 Kb)

Copyright Statement
This is an Accepted Manuscript of an article published by Taylor & Francis Group in Visual Cognition on 20/03/2017, available online at:

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