Publication details for Dr Bob KentridgeCavina-Pratesi C, Kentridge RW, Heywood CA & Milner AD (2009). Separate processing of texture and form in the ventral stream: evidence from fMRI and visual agnosia. Cerebral Cortex 20(2): 433-446.
- Publication type: Journal Article
- ISSN/ISBN: 1047-3211, 1460-2199
- DOI: 10.1093/cercor/bhp111
- Keywords: shape discrimination, texture discrimination, visual agnosia, fMRI, humans
- Further publication details on publisher web site
- Durham Research Online (DRO) - may include full text
Author(s) from Durham
Real-life visual object recognition requires the processing of more than just geometric (shape, size, and orientation) properties. Surface properties such as color and texture are equally important, particularly for providing information about the material properties of objects. Recent neuroimaging research suggests that geometric and surface properties are dealt with separately, within the lateral occipital cortex (LOC) and the collateral sulcus (CoS), respectively. Here we compared objects that either differed in aspect ratio or in surface texture only, keeping all other visual properties constant. Results on brain-intact participants confirmed that surface texture activates an area in the posterior CoS, quite distinct from the area activated by shape within LOC. We also tested two patients with visual object agnosia, one of whom (DF) performed well on the texture task but at chance on the shape task, while the other (MS) showed the converse pattern. This behavioral double dissociation was matched by a parallel neuroimaging dissociation, with activation in CoS but not LOC in patient DF, and activation in LOC but not CoS in patient MS. These data provide presumptive evidence that the areas respectively activated by shape and texture play a causally necessary role in the perceptual discrimination of these features.