title: Brain oscillatory 4-35 Hz EEG responses during an n-back task with complex visual stimuli.
abstract: Brain oscillatory responses of 4-35 Hz EEG frequencies elicited during performance of a visual n-back task with complex visual stimuli were assessed in 20 adult volunteers. Spectral power changes were assessed separately for target and non-target stimuli in four different memory load conditions (0, 1, 2, and 3-back). The presentation of both target and non-target stimuli elicited long-lasting ~4-8 Hz power increases, which were more prominent at the beginning of stimulus onset during presentation of target stimuli, as compared to non-target stimuli, in the 0-back memory load condition. ~8-25 Hz power decreases appeared at stimulus onset. These power decreases were more prominent during the presentation of target stimuli, as compared to non-target stimuli, and their duration increased as a function of memory load between the 0-, 1-, and 2-back, but not the 3-back, memory load conditions. The current results provide further evidence in support of the notion of a complex interplay between both ~4-8 Hz power increases and ~8-25 Hz power decreases during cognitive memory task performance.
authors.affiliation: Cognitive Science, Institute of Behavioural Sciences, University of Helsinki, P.O. Box 9, 00014 Helsinki, Finland. jussi.palomaki@helsinki.fi
authors.forename: Jussi
authors.initials: J
authors.lastname: Palomäki
authors.forename: Markus
authors.initials: M
authors.lastname: Kivikangas
authors.forename: Aleksander
authors.initials: A
authors.lastname: Alafuzoff
authors.forename: Tero
authors.initials: T
authors.lastname: Hakala
authors.forename: Christina M
authors.initials: CM
authors.lastname: Krause
mesh_terms: D000328:Adult; D001288:Attention / Q000502:physiology*; D001683:Biological Clocks / Q000502:physiology*; D001921:Brain / Q000502:physiology*; D004569:Electroencephalography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D008875:Middle Aged; D010364:Pattern Recognition, Visual / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods*; D055815:Young Adult