title: Resilience to the contralateral visual field bias as a window into object representations.
abstract: Viewing images of manipulable objects elicits differential blood oxygen level-dependent (BOLD) contrast across parietal and dorsal occipital areas of the human brain that support object-directed reaching, grasping, and complex object manipulation. However, it is unknown which object-selective regions of parietal cortex receive their principal inputs from the ventral object-processing pathway and which receive their inputs from the dorsal object-processing pathway. Parietal areas that receive their inputs from the ventral visual pathway, rather than from the dorsal stream, will have inputs that are already filtered through object categorization and identification processes. This predicts that parietal regions that receive inputs from the ventral visual pathway should exhibit object-selective responses that are resilient to contralateral visual field biases. To test this hypothesis, adult participants viewed images of tools and animals that were presented to the left or right visual fields during functional magnetic resonance imaging (fMRI). We found that the left inferior parietal lobule showed robust tool preferences independently of the visual field in which tool stimuli were presented. In contrast, a region in posterior parietal/dorsal occipital cortex in the right hemisphere exhibited an interaction between visual field and category: tool-preferences were strongest contralateral to the stimulus. These findings suggest that action knowledge accessed in the left inferior parietal lobule operates over inputs that are abstracted from the visual input and is contingent on analysis by the ventral visual pathway, consistent with its putative role in supporting object manipulation knowledge.
authors.affiliation: Department of Brain and Cognitive Sciences, University of Rochester, USA; Center for Visual Science, University of Rochester, USA.
authors.forename: Frank E
authors.initials: FE
authors.lastname: Garcea
authors.affiliation: Faculty of Psychology and Educational Sciences, University of Coimbra, Portugal; Proaction Laboratory, Faculty of Psychology and Educational Sciences, University of Coimbra, Portugal.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Kristensen
authors.affiliation: Faculty of Psychology and Educational Sciences, University of Coimbra, Portugal; Proaction Laboratory, Faculty of Psychology and Educational Sciences, University of Coimbra, Portugal. Electronic address: jorgealmeida@fpce.uc.pt.
authors.forename: Jorge
authors.initials: J
authors.lastname: Almeida
authors.affiliation: Department of Brain and Cognitive Sciences, University of Rochester, USA; Center for Visual Science, University of Rochester, USA; Department of Neurosurgery, University of Rochester, USA. Electronic address: mahon@rcbi.rochester.edu.
authors.forename: Bradford Z
authors.initials: BZ
authors.lastname: Mahon
mesh_terms: D000328:Adult; D015982:Bias; D001931:Brain Mapping / Q000379:methods; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D010296:Parietal Lobe / Q000502:physiology*; D010364:Pattern Recognition, Visual / Q000502:physiology*; D014794:Visual Fields / Q000502:physiology*; D014795:Visual Pathways / Q000502:physiology*; D055815:Young Adult
keywords: Dorsal stream; Functional MRI; Manipulable objects; Ventral stream; Visual processing