title: Neuromagnetic beta and gamma oscillations in the somatosensory cortex after music training in healthy older adults and a chronic stroke patient.
abstract: OBJECTIVE
  Extensive rehabilitation training can lead to functional improvement even years after a stroke. Although neuronal plasticity is considered as a main origin of such ameliorations, specific subtending mechanisms need further investigation. Our aim was to obtain objective neuromagnetic measures sensitive to brain reorganizations induced by a music-supported training.
  
  
  METHODS
  We applied 20-Hz vibrotactile stimuli to the index finger and the ring finger, recorded somatosensory steady-state responses with magnetoencephalography, and analyzed the cortical sources displaying oscillations synchronized with the external stimuli in two groups of healthy older adults before and after musical training or without training. In addition, we applied the same analysis for an anecdotic report of a single chronic stroke patient with hemiparetic arm and hand problems, who received music-supported therapy (MST).
  
  
  RESULTS
  Healthy older adults showed significant finger separation within the primary somatotopic map. Beta dipole sources were more anterior located compared to gamma sources. An anterior shift of sources and increases in synchrony between the stimuli and beta and gamma oscillations were observed selectively after music training. In the stroke patient a normalization of somatotopic organization was observed after MST, with digit separation recovered after training and stimulus induced gamma synchrony increased.
  
  
  CONCLUSIONS
  The proposed stimulation paradigm captures the integrity of primary somatosensory hand representation. Source position and synchronization between the stimuli and gamma activity are indices, sensitive to music-supported training. Responsiveness was also observed in a chronic stroke patient, encouraging for the music-supported therapy. Notably, changes in somatosensory responses were observed, even though the therapy did not involve specific sensory discrimination training.
  
  
  CONCLUSIONS
  The proposed protocol can be used for monitoring changes in neuronal organization during training and will improve the understanding of the brain mechanisms underlying rehabilitation.
authors.affiliation: Rotman Research Institute, Baycrest Centre, Toronto, ON, Canada; Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada.
authors.forename: Shahab
authors.initials: S
authors.lastname: Jamali
authors.affiliation: Center for Computer Research in Music and Acoustics, Department of Music, Stanford University, Stanford, CA, USA.
authors.forename: Takako
authors.initials: T
authors.lastname: Fujioka
authors.affiliation: Rotman Research Institute, Baycrest Centre, Toronto, ON, Canada; Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada. Electronic address: bross@research.baycrest.org.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Ross
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001611:Beta Rhythm / Q000502:physiology; D002908:Chronic Disease; D005260:Female; D005385:Fingers / Q000502:physiology; D065818:Gamma Rhythm / Q000502:physiology; D006225:Hand / Q000502:physiology; D006801:Humans; D015225:Magnetoencephalography / Q000379:methods; D008297:Male; D008875:Middle Aged; D009146:Music; D009147:Music Therapy; D009473:Neuronal Plasticity / Q000502:physiology; D026741:Physical Therapy Modalities; D013003:Somatosensory Cortex / Q000502:physiology* / Q000503:physiopathology*; D020521:Stroke / Q000503:physiopathology*; D000071939:Stroke Rehabilitation
keywords: Beta and gamma oscillation; Functional reorganization; Music-supported stroke rehabilitation; Primary somatosensory cortex; Somatosensory steady-state response; Somatotopic organization; Vibrotactile stimulation