title: Frontal theta activity reflects distinct aspects of mental fatigue.
abstract: Longer lasting performance in cognitively demanding tasks leads to an exhaustion of cognitive resources and to a state commonly described as mental fatigue. More specifically, the allocation and focusing of attention become less efficient with time on task. Additionally, the selection of even simple responses becomes more error prone. With respect to the recorded EEG, mental fatigue has been reported to be associated with an increase in frontal theta and frontal and occipital alpha activity. The present study focused on the time course of changes in behavior and in the EEG to characterize fatigue-related processes. Participants performed a spatial stimulus-response-compatibility task in eight blocks for an overall duration of 4h. Error rates increased continuously with time on task. Total alpha power was larger at the end compared to the beginning of the experiment. However, alpha power increased rapidly and reached its maximal amplitude already after 1h, whereas frontal theta showed a continuous increase with time on task, possibly related to increased effort to keep the performance level high. Time frequency analyses revealed power changes in the theta band induced by task relevant information that might be assigned to a drain of executive control capacities. Thus, frontal theta turned out to be a reliable marker of distinct changes in cognitive processing with increasing fatigue.
authors.affiliation: IfADo - Leibniz Research Centre for Working Environment and Human Factors, Dortmund, Germany. Electronic address: wascher@ifado.de.
authors.forename: Edmund
authors.initials: E
authors.lastname: Wascher
authors.affiliation: University of Fribourg, Switzerland.
authors.forename: Björn
authors.initials: B
authors.lastname: Rasch
authors.affiliation: Heinrich Heine University, Düsseldorf, Germany.
authors.forename: Jessica
authors.initials: J
authors.lastname: Sänger
authors.affiliation: IfADo - Leibniz Research Centre for Working Environment and Human Factors, Dortmund, Germany.
authors.forename: Sven
authors.initials: S
authors.lastname: Hoffmann
authors.affiliation: IfADo - Leibniz Research Centre for Working Environment and Human Factors, Dortmund, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Schneider
authors.affiliation: IfADo - Leibniz Research Centre for Working Environment and Human Factors, Dortmund, Germany.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Rinkenauer
authors.affiliation: IfADo - Leibniz Research Centre for Working Environment and Human Factors, Dortmund, Germany.
authors.forename: Herbert
authors.initials: H
authors.lastname: Heuer
authors.affiliation: Blindsight GmbH, Schlitz, Germany.
authors.forename: Ingmar
authors.initials: I
authors.lastname: Gutberlet
mesh_terms: D000328:Adult; D000513:Alpha Rhythm; D000704:Analysis of Variance; D004569:Electroencephalography; D005260:Female; D005583:Fourier Analysis; D005625:Frontal Lobe / Q000503:physiopathology*; D006801:Humans; D008297:Male; D005222:Mental Fatigue / Q000175:diagnosis* / Q000473:pathology* / Q000503:physiopathology*; D010775:Photic Stimulation; D011930:Reaction Time / Q000502:physiology; D013826:Theta Rhythm / Q000502:physiology*; D013997:Time Factors; D014796:Visual Perception; D055815:Young Adult
keywords: EEG; Frontal theta; Mental fatigue; Time on task