Information processing in working memory and event-related brain potentials.
Information processing in working memory was investigated in a paradigm with a pseudo-random sequence of visually presented consonants. The subjects' task was to memorize seven sequentially presented letters per trial and to recall the sequence (MEMORY task). Even-related potentials (ERPs) were selectively averaged for each of the seven positions of consonant presentation within a trial. The later a consonant was presented within a trial the smaller the P300 amplitude elicited by the consonant. The number of recall errors increased, however, from first to last presentation position. In a control task identical to the MEMORY condition consonant were presented. To limit the working memory load to one element, subjects had to count the number of letters within trials showing a specific physical criteria. P300 amplitude did not depend on presentation position. P300 was shown to covary with the amount of processing resources available for a task. We assume that increasing working memory load consumes processing resources that are not available for the processing of the incoming stimuli presented later in the trial.
Grune
K
K
Institute of Psychology, Humboldt University Berlin, Germany. kerstin.grune@rz.hu-berlin.de
Metz
A M
AM
Hagendorf
H
H
Fischer
S
S
D000328:Adult; D004569:Electroencephalography; D004585:Electrooculography; D018913:Event-Related Potentials, P300 / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D008606:Mental Processes / Q000502:physiology*; D011939:Mental Recall / Q000502:physiology; D008875:Middle Aged