title: Effects of attention and precision of exerted force on beta range EEG-EMG synchronization during a maintained motor contraction task.
abstract: OBJECTIVE
  The present study was aimed at investigating the effect of attention and precision level of exerted force on beta range EEG-EMG synchronization.
  
  
  METHODS
  We simultaneously recorded cortical electrical activity (EEG) in a bipolar manner from the contralateral sensorimotor areas and surface electromyographic (EMG) activity from the flexor digitorum superficialis muscle in 10 healthy subjects during a maintained motor contraction task at 8% of the maximal voluntary contraction (MVC) force level. The coherence between oscillatory processes in the EEG and EMG was calculated. Three different conditions were investigated: (i) performing the task with high precision (HP); (ii) performing the task with high precision and simultaneously performing a mental arithmetic task (HPAT), i.e. attention was divided between the motor task and the mental arithmetic task; and (iii) performing the task with low precision (LP).
  
  
  RESULTS
  We have found that the amount of beta range EEG-EMG synchronization decreases below the 95% confidence level when attention is divided between the motor task and the mental arithmetic task. The results also show that the frequency of beta range synchronization is higher with a higher level of precision but still lies within the beta frequency range (15-30 Hz).
  
  
  CONCLUSIONS
  The data indicate that beta range synchronization represents a state of the cortico-muscular network when attention is directed towards the motor task. The frequency of synchronization of this network is associated with, and possibly encodes, precision in force production.
authors.affiliation: Neurological Clinic, Albert-Ludwigs-University, Breisacherstrasse 64, 79106 Freiburg, Germany. kristeva@nz11.ukl.uni-freiburg.de
authors.forename: Rumyana
authors.initials: R
authors.lastname: Kristeva-Feige
authors.forename: Christoph
authors.initials: C
authors.lastname: Fritsch
authors.forename: Jens
authors.initials: J
authors.lastname: Timmer
authors.forename: Carl-Hermann
authors.initials: CH
authors.lastname: Lücking
mesh_terms: D000328:Adult; D000465:Algorithms; D001288:Attention / Q000502:physiology*; D001611:Beta Rhythm; D004576:Electromyography; D005246:Feedback / Q000502:physiology; D005260:Female; D005385:Fingers / Q000294:innervation / Q000502:physiology; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology; D008297:Male; D009044:Motor Cortex / Q000502:physiology; D018482:Muscle, Skeletal / Q000294:innervation / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology*; D013003:Somatosensory Cortex / Q000502:physiology