title: The Attentional Fields of Visual Search in Simultanagnosia and Healthy Individuals: How Object and Space Attention Interact.
abstract: Simultanagnosia is a deficit in which patients are unable to perceive multiple objects simultaneously. To date, it remains disputed whether this deficit results from disrupted object or space perception. We asked both healthy participants as well as a patient with simultanagnosia to perform different visual search tasks of variable difficulty. We also modulated the number of objects (target and distracters) presented. For healthy participants, we found that each visual search task was performed with a specific "attentional field" depending on the difficulty of visual object processing but not on the number of objects falling within this "working space." This was demonstrated by measuring the cost in reaction times using different gaze-contingent visible window sizes. We found that bilateral damage to the superior parietal lobule impairs the spatial integration of separable features (within-object processing), shrinking the attentional field in which a target can be detected, but causing no deficit in processing multiple objects per se.
authors.affiliation: ImpAct - Lyon Neuroscience Research Center, Inserm U1028, CNRS UMR 5292, Bron, France Université de Lyon, Biologie Humaine, Bron, France Hospices Civils de Lyon, Bron, France School of Optometry, University of Montreal, Montreal, QC, Canada.
authors.forename: A Z
authors.initials: AZ
authors.lastname: Khan
authors.affiliation: ImpAct - Lyon Neuroscience Research Center, Inserm U1028, CNRS UMR 5292, Bron, France Université de Lyon, Biologie Humaine, Bron, France Hospices Civils de Lyon, Bron, France.
authors.forename: M
authors.initials: M
authors.lastname: Prost-Lefebvre
authors.affiliation: ImpAct - Lyon Neuroscience Research Center, Inserm U1028, CNRS UMR 5292, Bron, France Université de Lyon, Biologie Humaine, Bron, France Hospices Civils de Lyon, Bron, France.
authors.forename: R
authors.initials: R
authors.lastname: Salemme
authors.affiliation: Centre for Neuroscience Studies, Queen's University, Kingston, ON, Canada.
authors.forename: G
authors.initials: G
authors.lastname: Blohm
authors.affiliation: ImpAct - Lyon Neuroscience Research Center, Inserm U1028, CNRS UMR 5292, Bron, France Université de Lyon, Biologie Humaine, Bron, France Hospices Civils de Lyon, Bron, France.
authors.forename: Y
authors.initials: Y
authors.lastname: Rossetti
authors.affiliation: ImpAct - Lyon Neuroscience Research Center, Inserm U1028, CNRS UMR 5292, Bron, France Université de Lyon, Biologie Humaine, Bron, France Hospices Civils de Lyon, Bron, France.
authors.forename: C
authors.initials: C
authors.lastname: Tilikete
authors.affiliation: ImpAct - Lyon Neuroscience Research Center, Inserm U1028, CNRS UMR 5292, Bron, France Université de Lyon, Biologie Humaine, Bron, France Hospices Civils de Lyon, Bron, France.
authors.forename: L
authors.initials: L
authors.lastname: Pisella
mesh_terms: D000328:Adult; D001288:Attention / Q000502:physiology; D002545:Brain Ischemia / Q000150:complications / Q000503:physiopathology; D005260:Female; D006801:Humans; D010296:Parietal Lobe / Q000503:physiopathology; D010468:Perceptual Disorders / Q000209:etiology / Q000503:physiopathology / Q000523:psychology; D010775:Photic Stimulation; D011581:Psychological Tests; D011930:Reaction Time; D013028:Space Perception / Q000502:physiology; D020521:Stroke / Q000150:complications / Q000503:physiopathology; D014796:Visual Perception / Q000502:physiology
keywords: feature integration; parallel; posterior parietal cortex; serial; simultanagnosia