Academic journal article Cognitive, Affective and Behavioral Neuroscience

A Right Visual Field Advantage for Visual Processing of Manipulable Objects

Academic journal article Cognitive, Affective and Behavioral Neuroscience

A Right Visual Field Advantage for Visual Processing of Manipulable Objects

Article excerpt

Published online: 4 August 2012

© Psychonomic Society, Inc. 2012

Abstract Information about object-associated manipulations is lateralized to leftparietal regions, while information about the visual form of tools is represented bilaterally in ventral occipito-temporal cortex. It is unknown how lateralization of motor-relevant information in left-hemisphere dorsal stream regions may affect the visual processing of manipulable objects. We used a lateralized masked priming paradigm to test for a right visual field (RVF) advantage in tool processing. Target stimuli were tools and animals, and briefly presented primes were identical to or scrambled versions of the targets. In Experiment 1, primes were presented either to the leftor to the right of the centrally presented target, while in Experiment 2, primes were presented in one of eight locations arranged radially around the target. In both experiments, there was a RVF advantage in priming effects for tool but not for animal targets. Control experiments showed that participants were at chance for matching the identity of the lateralized primes in a picture-word matching experiment and also ruled out a general RVF speedof- processing advantage for tool images. These results indicate that the overrepresentation of tool knowledge in the lefthemisphere affects visual object recognition and suggests that interactions between the dorsal and ventral streams occurs during object categorization.

Keywords Semantics . Object use . Dorsal stream . Laterality . Priming . Visual object recognition

Introduction

An important issue is how basic principles of organization of the primate visual system contribute to determining the cortical organization of object knowledge. The first cortical stage of visual processing in the primate brain processes information from the contralateral visual field: Early visual regions in the lefthemisphere process stimuli presented to the right visual field (RVF) across both eyes, and early visual regions in the right hemisphere process stimuli presented to the leftvisual field (LVF) across both eyes (e.g., Engel, Glover, & Wandell, 1997; Felleman & Van Essen, 1991). Independently of this property of the visual system, some domains of information are lateralized to the leftor right hemisphere. For example, language is predominantly leftlateralized in the majority of individuals (e.g., Gazzaniga & Smylie, 1984; Knecht et al., 2000). Investigations of hemispheric biases in visual processing of different classes of stimuli have found visual field advantages contralateral to the hemisphere that differentially represents that domain. For instance, there is a strong RVF advantage for recognition of printed words (e.g., Bub & Lewine, 1988; Finkbeiner, Almeida, & Caramazza, 2006; Hunter & Brysbaert, 2008). Knowledge about how to manipulate objects is also strongly leftlateralized in the majority of individuals (Johnson-Frey, 2004; Kroliczak &Frey, 2009). The goal of the present investigation was to test the hypothesis that the overrepresentation of tool knowledge in the lefthemisphere leads to a RVF advantage for visual processing of tool stimuli.

A second principle of organization within the primate visual system that is relevant to understanding hemispheric lateralization of tools is the division of labor between the dorsal and ventral visual pathways. The dorsal visual pathway projects from V1 to dorsal occipital cortex and posterior parietal cortex, while the ventral stream projects from V1 to ventral and lateral occipito-temporal regions, terminating in anterior temporal cortex (Goodale & Milner, 1992; Goodale, Milner, Jakobson, & Carey, 1991; Ungerleider & Mishkin, 1982; see also Goodale, Kroliczak, &Westwood, 2005; Ungerleider, 1995). The classic understanding of the division of labor between these two streams is that the dorsal stream is critical for extracting visuomotor and spatial information relevant to action, while the ventral stream extracts object identity across variations in size, orientation, luminance, and distance. …

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