title: Now I am ready-now i am not: The influence of pre-TMS oscillations and corticomuscular coherence on motor-evoked potentials.
abstract: There is a growing body of research on the functional role of oscillatory brain activity. However, its relation to functional connectivity has remained largely obscure. In the sensorimotor system, movement-related changes emerge in the α (8-14 Hz) and β (15-30 Hz) range (event-related desynchronization, ERD, before and during movement; event-related synchronization, ERS, after movement offset). Some studies suggest that β-ERS may functionally inhibit new movements. According to the gating-by-inhibition framework ( Jensen and Mazaheri 2010), we expected that the ERD would go along with increased corticomuscular coupling, and vice versa. By combining transcranial magnetic stimulation (TMS) and electroencephalography, we were directly able to test this hypothesis. In a reaction time task, single TMS pulses were delivered randomly during ERD/ERS to the motor cortex. The motor-evoked potential (MEP) was then related to the β and α frequencies and corticomuscular coherence. Results indicate that MEPs are smaller when preceded by high pre-TMS β-band power and low pre-TMS α-band corticomuscular coherence (and vice versa) in a network of motor-relevant areas comprising frontal, parietal, and motor cortices. This confirms that an increase in rhythms that putatively reflect functionally inhibited states goes along with weaker coupling of the respective brain regions.
authors: Department of Psychology, University of Konstanz, Konstanz, Germany.
authors: Hannah
authors: H
authors: Schulz
authors: Department of Psychology, University of Konstanz, Konstanz, Germany.
authors: Teresa
authors: T
authors: Ubelacker
authors: AG Multisensory Integration, Charité Universitätsmedizin, Berlin, Berlin, Germany.
authors: Julian
authors: J
authors: Keil
authors: Center for Mind/Brain Sciences, University of Trento, Trento, Italy.
authors: Nadia
authors: N
authors: Müller
authors: Center for Mind/Brain Sciences, University of Trento, Trento, Italy.
authors: Nathan
authors: N
authors: Weisz
mesh_terms: D000328:Adult; D001931:Brain Mapping; D003344:Cortical Synchronization / Q000502:physiology*; D004569:Electroencephalography; D004576:Electromyography; D019054:Evoked Potentials, Motor / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D009068:Movement / Q000502:physiology; D018482:Muscle, Skeletal / Q000294:innervation*; D010775:Photic Stimulation; D011597:Psychomotor Performance / Q000502:physiology*; D011930:Reaction Time; D066191:Sensorimotor Cortex / Q000502:physiology*; D013057:Spectrum Analysis; D013997:Time Factors; D050781:Transcranial Magnetic Stimulation; D055815:Young Adult
keywords: ERD/ERS; TMS; corticomuscular coherence; gating by inhibition; motor network