title: The role of beta-gamma oscillations in unexpected rewards processing.
abstract: Reward processing in humans is carried out by an extensive fronto-subcortical network that might be coordinated by fast oscillatory electrical activity. Previous studies have identified an increase in beta-gamma oscillatory activity after the processing of positive feedback stimuli but the functional role of this electroencephalographic (EEG) correlate remains unclear. In the present study, we used event-related brain potentials (ERPs) and trial-by-trial wavelet-based time-frequency analysis of the EEG signal to investigate the effects of expectancy and magnitude of positive and negative feedbacks associated with monetary gains and losses in a gambling task. Large increase of beta-gamma oscillatory activity only in unexpected monetary gains was observed,irrespective of its magnitude. Based on recent findings we propose that this increase in beta-gamma oscillatory activity might reflect a general cognitive mechanism in charge of monitoring unexpected positive events based on feedback processing.
authors.affiliation: Cognition and Brain Plasticity Group, [Bellvitge Biomedical Research Institute-] IDIBELL, L'Hospitalet de Llobregat, Barcelona, 08097, Spain.
authors.forename: Azadeh
authors.initials: A
authors.lastname: HajiHosseini
authors.forename: Antoni
authors.initials: A
authors.lastname: Rodríguez-Fornells
authors.forename: Josep
authors.initials: J
authors.lastname: Marco-Pallarés
mesh_terms: D000328:Adult; D059031:Anticipation, Psychological / Q000502:physiology*; D001683:Biological Clocks / Q000502:physiology*; D002540:Cerebral Cortex / Q000502:physiology*; D004569:Electroencephalography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D012201:Reward