Brain oscillatory 4-30 Hz responses during a visual n-back memory task with varying memory load.

Full Abstract

Brain oscillatory responses of 4-30 Hz EEG frequencies elicited during the performance of a visual n-back task were examined in 36 adult volunteers. Event-related desynchronization (ERD) and event-related synchronization (ERS) responses were examined separately for targets and non-targets in four different memory load conditions (0-, 1-, 2- and 3-back). The presentation of all stimuli in all memory load conditions elicited long-lasting theta frequency (approximately 4-6 Hz) ERS responses which were of greater magnitude for the target stimuli as compared to the non-target stimuli. Alpha frequency range (approximately 8-12 Hz) ERD responses were observed in all memory load conditions for both targets and non-targets. The duration of these alpha ERD responses increased with increasing memory load and reaction time. In all memory load conditions, early appearing beta rhythm (approximately 14-30 Hz) ERD responses were elicited, and with increasing memory load, these beta ERD responses became longer in duration. Additionally, beta ERS responses were observed in the 0- and 1-back memory load conditions. The current results reveal a complex interplay between brain oscillations at different frequencies during a cognitive task performance.

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Author information

Author/s: Pesonen, Mirka (M); Hämäläinen, Heikki (H); Krause, Christina M (CM);

Affiliation: Cognitive Science Unit, Department of Psychology, University of Helsinki, P.O. Box 9, 00014 Helsinki, Finland. mirka.pesonen(-atsign-)helsinki.fi

Journal and publication information

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

Journal: Brain research (Brain Res), published in Netherlands. (Language: eng)

Reference: 2007-Mar; vol 1138 (issue ) : pp 171-7

Dates: Created 2007/02/27; Completed 2007/05/21;

PMID: 17270151, status: MEDLINE (last retrieval date: 12/26/2008)

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MeSH headings (categories)

This article was linked to the MESH Headings shown below.

Male
Memory - physiology
Photic Stimulation
Reaction Time
Theta Rhythm
Visual Perception - physiology

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