Brain potentials distinguish new and studied objects during working memory.

Full 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. (c) 2007 Wiley-Liss, Inc.

Author information

Author/s: Guo, Chunyan (C); Lawson, Adam L (AL); Zhang, Qin (Q); Jiang, Yang (Y);

Affiliation: Department of Psychology, Capital Normal University, Beijing, China.

Grants: K01 AG00986 (Agency:NIA NIH HHS) ; P50 AG05144-21 (Agency:NIA NIH HHS)

Journal and publication information

Publication Type: Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't

Journal: Human brain mapping (Hum Brain Mapp), published in United States. (Language: eng)

Reference: 2008-Apr; vol 29 (issue 4) : pp 441-52

Dates: Created 2008/03/13; Completed 2008/06/30;

PMID: 17497630, status: MEDLINE (last retrieval date: 2/18/2009, IMS Date: )

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

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