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An electrophysiological measure of visual short‐term memory capacity within and across hemifields
Author(s) -
Delvenne JeanFrancois,
Kaddour Laura A.,
Castronovo Julie
Publication year - 2011
Publication title -
psychophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.661
H-Index - 156
eISSN - 1469-8986
pISSN - 0048-5772
DOI - 10.1111/j.1469-8986.2010.01079.x
Subject(s) - psychology , electrophysiology , visual field , visual short term memory , term (time) , amplitude , communication , cognitive psychology , visual memory , neuroscience , cognition , physics , optics , quantum mechanics
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.