title: The evolution of a disparity decision in human visual cortex.
abstract: We used fMRI-informed EEG source-imaging in humans to characterize the dynamics of cortical responses during a disparity-discrimination task. After the onset of a disparity-defined target, decision-related activity was found within an extended cortical network that included several occipital regions of interest (ROIs): V4, V3A, hMT+ and the Lateral Occipital Complex (LOC). By using a response-locked analysis, we were able to determine the timing relationships in this network of ROIs relative to the subject's behavioral response. Choice-related activity appeared first in the V4 ROI almost 200 ms before the button press and then subsequently in the V3A ROI. Modeling of the responses in the V4 ROI suggests that this area provides an early contribution to disparity discrimination. Choice-related responses were also found after the button-press in ROIs V4, V3A, LOC and hMT+. Outside the visual cortex, choice-related activity was found in the frontal and temporal poles before the button-press. By combining the spatial resolution of fMRI-informed EEG source imaging with the ability to sort out neural activity occurring before, during and after the behavioral manifestation of the decision, our study is the first to assign distinct functional roles to the extra-striate ROIs involved in perceptual decisions based on disparity, the primary cue for depth.
authors: Université de Toulouse, UPS, Centre de Recherche Cerveau et Cognition, France; CNRS, CerCo, Toulouse, France. Electronic address: cottereau@cerco.ups-tlse.fr.
authors: Benoit R
authors: BR
authors: Cottereau
authors: School of Psychology and Neuroscience, St Mary's Quad, South Street, University of St Andrews, St Andrews KY16 9JP, UK.
authors: Justin M
authors: JM
authors: Ales
authors: Department of Psychology, Jordan Hall, Building 01-420, Stanford University, 450 Serra Mall, Stanford, CA 94305, USA.
authors: Anthony M
authors: AM
authors: Norcia
mesh_terms: D000328:Adult; D000368:Aged; D001931:Brain Mapping / Q000379:methods*; D002755:Choice Behavior / Q000502:physiology*; D003463:Cues; D004569:Electroencephalography / Q000379:methods; D005260:Female; D006801:Humans; D007600:Judgment / Q000502:physiology*; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D009415:Nerve Net / Q000502:physiology*; D015357:Vision Disparity / Q000502:physiology*; D014793:Visual Cortex / Q000502:physiology*; D055815:Young Adult
keywords: Binocular vision; Decision making; Disparity processing; EEG; Neural imaging