title: Oscillatory interaction between the hand area of human primary motor cortex and finger muscles during steady-state isometric contraction.
abstract: OBJECTIVE
  To compare the magnitudes of β-band coherence between the primary motor cortex (M1) and electromyogram (EMG) for finger muscles, and to determine whether M1-EMG coherence is related to the stability of muscle contraction.
  
  
  METHODS
  Cortical signals and EMG during steady-state isometric contraction of right thumb muscle (flexor pollicis brevis (FPB)) or right little finger muscle (flexor digiti minimi brevis (FDMB)) were recorded simultaneously with magnetoencephalography system from 13 right-handed healthy subjects.
  
  
  RESULTS
  The magnitudes of β-band M1-EMG coherence and spectral power in the M1 for the FPB muscle were greater than that for the FDMB muscle (P < 0.001 and P < 0.005, respectively). The stability of EMG for the FPB was higher than that for FDMB (P < 0.001). Greater levels of β-band M1-EMG coherence were associated with higher levels of EMG stability (P < 0.05). The mean dipole sources of the FPB muscle were located more laterally, inferiorly and anteriorly than that of FDMB in the M1 hand area (P < 0.005).
  
  
  CONCLUSIONS
  The strength of β-band M1-EMG coherence would play an important role in the stability level of finger-muscle contraction.
  
  
  CONCLUSIONS
  The β-band M1-EMG coherence may reflect effective oscillatory interaction between the M1 and finger muscle during steady-state motor output.
authors.affiliation: Interdisciplinary Program in Neuroscience, Seoul National University, Seoul, South Korea.
authors.forename: Manyoel
authors.initials: M
authors.lastname: Lim
authors.forename: June Sic
authors.initials: JS
authors.lastname: Kim
authors.forename: Chun Kee
authors.initials: CK
authors.lastname: Chung
mesh_terms: D000328:Adult; D001683:Biological Clocks / Q000502:physiology*; D004569:Electroencephalography; D019054:Evoked Potentials, Motor / Q000502:physiology*; D005260:Female; D005385:Fingers / Q000294:innervation / Q000502:physiology*; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology*; D008297:Male; D009044:Motor Cortex / Q000033:anatomy & histology / Q000502:physiology*; D018482:Muscle, Skeletal / Q000294:innervation / Q000502:physiology*; D055815:Young Adult