The effects of memory load and stimulus relevance on the EEG during a visual selective memory search task: An ERP and ERD/ERS study

Psychophysiological correlates of selective attention and working memory were investigated in a group of 18 healthy children using a visually presented selective memory search task. Subjects had to memorize one (load1) or 3 (load3) letters (memory set) and search for these among a recognition set co...

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Veröffentlicht in:Clinical neurophysiology 2006-04, Vol.117 (4), p.871-884
Hauptverfasser: Gomarus, H. Karin, Althaus, Monika, Wijers, Albertus A., Minderaa, Ruud B.
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Sprache:eng
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Zusammenfassung:Psychophysiological correlates of selective attention and working memory were investigated in a group of 18 healthy children using a visually presented selective memory search task. Subjects had to memorize one (load1) or 3 (load3) letters (memory set) and search for these among a recognition set consisting of 4 letters only if the letters appeared in the correct (relevant) color. Event-related potentials (ERPs) as well as alpha and theta event-related synchronization and desynchronization (ERD/ERS) were derived from the EEG that was recorded during the task. In the ERP to the memory set, a prolonged load-related positivity was found. In response to the recognition set, effects of relevance were manifested in an early frontal positivity and a later frontal negativity. Effects of load were found in a search-related negativity within the attended category and a suppression of the P3-amplitude. Theta ERS was most pronounced for the most difficult task condition during the recognition set, whereas alpha ERD showed a load-effect only during memorization. The manipulation of stimulus relevance and memory load affected both ERP components and ERD/ERS. The present paradigm may supply a useful method for studying processes of selective attention and working memory and can be used to examine group differences between healthy controls and children showing psychopathology.
ISSN:1388-2457
1872-8952
DOI:10.1016/j.clinph.2005.12.008