Open AccessBrain potentials distinguish new and studied objects during working memory
Author(s) -
Guo Chunyan,
Lawson Adam L.,
Zhang Qin,
Jiang Yang
Publication year - 2008
Publication title -
human brain mapping
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.005
H-Index - 191
eISSN - 1097-0193
pISSN - 1065-9471
DOI - 10.1002/hbm.20409
Subject(s) - psychology , working memory , task (project management) , matching (statistics) , object (grammar) , contrast (vision) , cognitive psychology , electroencephalography , event related potential , recognition memory , neuroscience , audiology , cognition , artificial intelligence , computer science , medicine , statistics , mathematics , management , economics
Abstract We investigated brain responses to matching versus nonmatching objects in working memory (WM) with a modified delayed match‐to‐sample task using event‐related potentials (ERPs). In addition, ERP correlates of new items (new matches/new nonmatches) and previously studied items (studied matches/studied nonmatches) were examined in the WM task. Half of the common visual objects were initially studied until 95% accuracy was attained and half were new. Each memory trial began with the presentation of a sample object followed by nine test objects. Participants indicated whether each test item was the same as the object held in mind (i.e., match) or a nonmatch. Compared to studied matches, new matches evoked activity that was 50 ms earlier and largest at frontal sites. In contrast, P3 activity associated with studied nonmatches was larger than for new nonmatches at mostly posterior sites, which parallels previously reported old–new ERP effects. The ERP source analysis further confirms that the cortical mechanisms underlying matching objects and rejecting irrelevant objects during the task are both temporally and spatially distinct. Moreover, our current findings suggest that prior learning affects brain responses to matching visual items during a WM task. Hum Brain Mapp 2008. © 2007 Wiley‐Liss, Inc.