August 2016
Volume 16, Issue 12
Open Access
Vision Sciences Society Annual Meeting Abstract  |   September 2016
The attentional fields of visual search in simultanagnosia and healthy individuals: How object and space attention interact
Author Affiliations
  • Aarlenne Khan
    School of Optometry, University of Montreal, Montreal, QC, Canada
  • Myriam Prost-Lefebvre
    ImpAct Team, Lyon Neuroscience Research Center, Inserm U1028, CNRS UMR 5292, Bron, France
  • Romeo Salemme
    ImpAct Team, Lyon Neuroscience Research Center, Inserm U1028, CNRS UMR 5292, Bron, France
  • Gunnar Blohm
    Centre for Neuroscience Studies, Queen's University, Kingston, ON, Canada
  • Yves Rossetti
    ImpAct Team, Lyon Neuroscience Research Center, Inserm U1028, CNRS UMR 5292, Bron, France
  • Laure Pisella
    ImpAct Team, Lyon Neuroscience Research Center, Inserm U1028, CNRS UMR 5292, Bron, France
Journal of Vision September 2016, Vol.16, 1323. doi:10.1167/16.12.1323
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      Aarlenne Khan, Myriam Prost-Lefebvre, Romeo Salemme, Gunnar Blohm, Yves Rossetti, Laure Pisella; The attentional fields of visual search in simultanagnosia and healthy individuals: How object and space attention interact . Journal of Vision 2016;16(12):1323. doi: 10.1167/16.12.1323.

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      © 2017 Association for Research in Vision and Ophthalmology.

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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 (both pop-out and serial) of variable difficulty using different gaze-contingent visible window sizes. This allowed us to determine the size of the attentional span used for each visual search task; only visible windows that were smaller than the specific attentional span used for the task resulted in a cost in reaction times to find the search target. To determine whether this attentional span varied according to object or space, we also modulated the number of objects (target and distracters). For healthy participants, we found that each visual search task was performed with a specific attentional span depending on the difficulty of visual object processing but not on the number of objects falling within this space. For the patient with simultanagnosia, we found a reduced attentional span compared to controls but only for search tasks with objects that were made up of separable features. This did not vary according to the number of objects. Thus, we conclude that bilateral damage to the superior parietal lobule (SPL) impairs the spatial integration of separable features (within-object processing), shrinking the attentional span within which a target can be detected, but causing no deficit in processing multiple objects per se.

Meeting abstract presented at VSS 2016

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