title: Delta-Band Oscillations in Motor Regions Predict Hand Selection for Reaching.
abstract: Current models hold that action selection is achieved by competitive interactions between co-existing motor representations associated with each potential action. Critically, selection via competition requires biasing signals to enable one of these alternatives to be selected. This study tested the hypothesis that selection is related to the prestimulus excitability of neuronal ensembles in which movements are encoded, as assessed through the phase of delta-band oscillations (2-4 Hz). Electroencephalography was recorded while participants performed speeded reaches toward appearing visual targets using the hand of their choice. The target locations were controlled such that only targets for which the left and right hands were selected equally often were used for analysis. Results revealed that hand selection as well as reach reaction times strongly depended upon the instantaneous phase of delta at the moment of target onset. This effect was maximal over contralateral motor regions, and occurred in the absence of prestimulus alpha- (8-12 Hz) and beta-band (15-30 Hz) amplitude modulations. These findings demonstrate that the excitability of motor regions acts as a modulatory factor for hand choice during reaching. They extend current models by showing that action selection is related to the underlying brain state independently of previously known decision variables.
authors.affiliation: Département de kinanthropologie, Faculté des sciences de l'activité physique, Université de Sherbrooke, Sherbrooke, Québec J1K 2R1, Canada.
authors.forename: Audrey
authors.initials: A
authors.lastname: Hamel-Thibault
authors.affiliation: Département de kinanthropologie, Faculté des sciences de l'activité physique, Université de Sherbrooke, Sherbrooke, Québec J1K 2R1, Canada.
authors.forename: François
authors.initials: F
authors.lastname: Thénault
authors.affiliation: Département de médecine nucléaire et de radiobiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec J1H 5N4, Canada.|Département de radiologie diagnostique, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec J1H 5N4, Canada.
authors.forename: Kevin
authors.initials: K
authors.lastname: Whittingstall
authors.affiliation: Département de kinanthropologie, Faculté des sciences de l'activité physique, Université de Sherbrooke, Sherbrooke, Québec J1K 2R1, Canada.
authors.forename: Pierre-Michel
authors.initials: PM
authors.lastname: Bernier
mesh_terms: D000328:Adult; D003700:Delta Rhythm / Q000502:physiology*; D005260:Female; D005544:Forecasting; D007839:Functional Laterality / Q000502:physiology; D006225:Hand / Q000502:physiology*; D006801:Humans; D008297:Male; D009044:Motor Cortex / Q000502:physiology*; D009068:Movement / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D011930:Reaction Time / Q000502:physiology*; D055815:Young Adult
keywords: EEG; action selection; delta oscillations; reaching