An electrophysiological measure of visual short‐term memory capacity within and across hemifields |
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Authors: | Jean‐Francois Delvenne Laura A. Kaddour Julie Castronovo |
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Affiliation: | 1. Institute of Psychological Sciences, University of Leeds, United Kingdom;2. Unité de Neurosciences Cognitives, University of Louvain, Belgium |
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Abstract: | Recent electrophysiological research has identified a specific contralateral correlate of the contents of visual short‐term memory (VSTM). This posterior contralateral delay activity (CDA) persists during the retention period, and its amplitude is modulated by the number of items held at any one time. Here we show that, despite the contralateral nature of this activity, its amplitude is modulated by the number of objects from both hemifields. When objects from one side of the visual field are held in memory, CDA activity increased for arrays of one, two, and three objects, but stopped getting larger for arrays of four objects. However, when objects from both sides are memorized at the same time, CDA activity reached its asymptotic limit for arrays of two objects per side. These results suggest that, in spite of being contralaterally organized, VSTM is limited by the number of objects from both hemifields. |
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Keywords: | Visual working memory Visual short‐term memory Capacity limits Bilateral presentation CDA Event‐related potentials |
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