title: Beta-Band Oscillations Represent Auditory Beat and Its Metrical Hierarchy in Perception and Imagery.
abstract: Dancing to music involves synchronized movements, which can be at the basic beat level or higher hierarchical metrical levels, as in a march (groups of two basic beats, one-two-one-two …) or waltz (groups of three basic beats, one-two-three-one-two-three …). Our previous human magnetoencephalography studies revealed that the subjective sense of meter influences auditory evoked responses phase locked to the stimulus. Moreover, the timing of metronome clicks was represented in periodic modulation of induced (non-phase locked) β-band (13-30 Hz) oscillation in bilateral auditory and sensorimotor cortices. Here, we further examine whether acoustically accented and subjectively imagined metric processing in march and waltz contexts during listening to isochronous beats were reflected in neuromagnetic β-band activity recorded from young adult musicians. First, we replicated previous findings of beat-related β-power decrease at 200 ms after the beat followed by a predictive increase toward the onset of the next beat. Second, we showed that the β decrease was significantly influenced by the metrical structure, as reflected by differences across beat type for both perception and imagery conditions. Specifically, the β-power decrease associated with imagined downbeats (the count "one") was larger than that for both the upbeat (preceding the count "one") in the march, and for the middle beat in the waltz. Moreover, beamformer source analysis for the whole brain volume revealed that the metric contrasts involved auditory and sensorimotor cortices; frontal, parietal, and inferior temporal lobes; and cerebellum. We suggest that the observed β-band activities reflect a translation of timing information to auditory-motor coordination.
  
  
  CONCLUSIONS
  With magnetoencephalography, we examined β-band oscillatory activities around 20 Hz while participants listened to metronome beats and imagined musical meters such as a march and waltz. We demonstrated that β-band event-related desynchronization in the auditory cortex differentiates between beat positions, specifically between downbeats and the following beat. This is the first demonstration of β-band oscillations related to hierarchical and internalized timing information. Moreover, the meter representation in the β oscillations was widespread across the brain, including sensorimotor and premotor cortices, parietal lobe, and cerebellum. The results extend current understanding of the role of β oscillations in neural processing of predictive timing.
authors.affiliation: Centre for Computer Research in Music and Acoustics and Neuroscience Institute, Stanford University, Stanford, California 94305, takako@ccrma.stanford.edu.
authors.forename: Takako
authors.initials: T
authors.lastname: Fujioka
authors.affiliation: Rotman Research Institute, Toronto, Ontario M6A 2E1, Canada, Department of Medical Biophysics, University of Toronto, Toronto, Ontario M5G 1L7, Canada, and.
authors.forename: Bernhard
authors.identifier: http://orcid.org/0000-0001-7290-631X
authors.initials: B
authors.lastname: Ross
authors.affiliation: Rotman Research Institute, Toronto, Ontario M6A 2E1, Canada, McMaster Institute for Music and the Mind and Department of Psychology, Neuroscience and Behaviour, McMaster University, Hamilton, Ontario L8S 4L8, Canada.
authors.forename: Laurel J
authors.initials: LJ
authors.lastname: Trainor
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods*; D000328:Adult; D001303:Auditory Cortex / Q000502:physiology*; D001307:Auditory Perception / Q000502:physiology*; D001611:Beta Rhythm / Q000502:physiology*; D005072:Evoked Potentials, Auditory / Q000502:physiology; D005260:Female; D006801:Humans; D007092:Imagination / Q000502:physiology*; D015225:Magnetoencephalography / Q000379:methods; D008297:Male; D010507:Periodicity; D055815:Young Adult
keywords: ERD; event-related desynchronization; magnetoencephalography; predictive coding; timing processing