title: The best of both worlds: phase-reset of human EEG alpha activity and additive power contribute to ERP generation.
abstract: Some authors have proposed that event-related potentials (ERPs) are generated by a neuronal response which is additive to and independent of ongoing activity, others demonstrated that they are generated by partial phase-resetting of ongoing activity. We investigated the relationship between event-related oscillatory activity in the alpha band and prestimulus levels of ongoing alpha activity on ERPs. EEG was recorded from 23 participants performing a visual discrimination task. Individuals were assigned to one of three groups according to the amount of prestimulus total alpha activity, and distinct differences of the event-related EEG dynamics between groups were observed. While all groups exhibited an event-related increase in phase-locked (evoked) alpha activity, only individuals with sustained prestimulus alpha activity showed alpha-blocking, that is, a considerable decrease of poststimulus non-phase-locked alpha activity. In contrast, individuals without observable prestimulus total alpha activity showed a concurrent increase of phase-locked and non-phase-locked alpha activity after stimulation. Data from this group seems to be in favor of an additive event-related neuronal response without alpha-blocking. However, the dissociable EEG dynamics of total and evoked alpha activities together with a complementary simulation analysis indicated a partial event-related reorganization of ongoing brain activity. We conclude that both partial phase-resetting and partial additive power contribute dynamically to the generation of ERPs. The prestimulus brain state exerts a prominent influence on event-related brain responses.
authors.affiliation: Department of Biological Psychology, Otto-von-Guericke University, Magdeburg, Germany.
authors.forename: Byoung-Kyong
authors.initials: BK
authors.lastname: Min
authors.forename: Niko A
authors.initials: NA
authors.lastname: Busch
authors.forename: Stefan
authors.initials: S
authors.lastname: Debener
authors.forename: Cornelia
authors.initials: C
authors.lastname: Kranczioch
authors.forename: Simon
authors.initials: S
authors.lastname: Hanslmayr
authors.forename: Andreas K
authors.initials: AK
authors.lastname: Engel
authors.forename: Christoph S
authors.initials: CS
authors.lastname: Herrmann
mesh_terms: D000328:Adult; D000513:Alpha Rhythm; D003627:Data Interpretation, Statistical; D004192:Discrimination, Psychological / Q000502:physiology; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008959:Models, Neurological; D011597:Psychomotor Performance / Q000502:physiology; D014796:Visual Perception / Q000502:physiology