Modulation of human corticomuscular beta-range coherence with low-level static forces.
Although corticomuscular synchronization in the beta range (15-30 Hz) was shown to occur during weak steady-state contractions, an examination of low-level forces around 10% of the maximum voluntary contraction (MVC) is still missing. We addressed this question by investigating coherence between electroencephalogram (EEG) and electromyogram (EMG) as well as cortical spectral power during a visuomotor task. Eight healthy right-handed subjects compensated isometrically static forces at a level of 4% and 16% of MVC with their right index finger. While 4% MVC was accompanied by low coherence values in the middle to high beta frequency range (25-30 Hz), a significant increase of coherence mainly confined to low beta frequencies (19-20 Hz) was observed with force of 16% MVC. Furthermore, this increase was associated with better performance, as reflected in decreased relative error in force during 16% MVC. We additionally show that periods of good motor performance within each condition were associated with higher values of EEG-EMG coherence and spectral power. In conclusion, our results suggest a role for beta-range corticomuscular coherence in effective sensorimotor integration, thus stabilizing corticospinal communication.
Neurological Clinic, Albert-Ludwigs-University, Breisacher Strasse 64, 79106 Freiburg, Germany.
Matthias
M
Witte
Luis
L
Patino
Agnieszka
A
Andrykiewicz
Marie-Claude
MC
Hepp-Reymond
Rumyana
R
Kristeva
D000328:Adult; D001611:Beta Rhythm; D003344:Cortical Synchronization; D004569:Electroencephalography; D004576:Electromyography; D005260:Female; D005385:Fingers / Q000502:physiology; D006801:Humans; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology*