Examining the inhibitory role of motor cortex mu and beta frequency bands - a combined EEG/TMS study

Abstract

Event Abstract Back to Event Examining the inhibitory role of motor cortex mu and beta frequency bands - a combined EEG/TMS study Hannah Schulz1*, Nathan Weisz1, Julian Keil1 and Thomas Hartmann1 1 University of Konstanz, Germany There is a growing body of research on the functional role of oscillatory brain activity in specific frequency bands. It is assumed that the different frequencies are either more related to excitatory states, such as gamma frequency bands, whereas alphalike brain rhythms appear to be more related to inhibitory states. In the sensorimotor system a characteristic pattern of movement related changes emerges in the mu (8-14Hz) and beta (15-30Hz) range: Following a desynchronisation before and during movement, beta and mu frequency power exceeds baseline after movement offset before returning to baseline values. Though the precise functional role of this rebound is not yet well known, some behavioural and TMS studies suggest a functional inhibition of motor cortex during this period. By combining TMS and EEG, we were able to test this hypothesis directly. We investigated the electromyographic (EMG) reaction elicited by TMS applied to the motor cortex, following a brief motor response in a simple reaction time task. Neuronavigated suprathreshold TMS singlepulses were applied to the motorcortex while recording EEG and first dorsal interosseous muscle EMG. Pulses were delivered randomly in the time window of the mu and beta rebound, which we determined in a prior pilot study. The amplitude of the motor evoked potential of the contralateral hand, as well as corticospinal coherence was then correlated to the fluctuation of beta and mu frequencies. Preliminary results indicate that MEP amplitude as well as corticospinal coherence is related to the time course of the rebound. This confirms our hypothesis, which ascribes an inhibitory role to the dominant motor resting rhythms. Further analysis will be performed in order to scrutinize the precize nature of this phenomena, as well as the question regarding functional differences between motor mu and beta rhythms. Conference: Biomag 2010 - 17th International Conference on Biomagnetism , Dubrovnik, Croatia, 28 Mar - 1 Apr, 2010. Presentation Type: Poster Presentation Topic: Instrumentation and Multi-modal Integrations: MEG, Low-field MRI,EEG, fMRI,TMS,NIRS Citation: Schulz H, Weisz N, Keil J and Hartmann T (2010). Examining the inhibitory role of motor cortex mu and beta frequency bands - a combined EEG/TMS study. Front. Neurosci. Conference Abstract: Biomag 2010 - 17th International Conference on Biomagnetism . doi: 10.3389/conf.fnins.2010.06.00013 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 18 Mar 2010; Published Online: 18 Mar 2010. * Correspondence: Hannah Schulz, University of Konstanz, Konstanz, Germany, hannah.schulz@uni-konstanz.de Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Hannah Schulz Nathan Weisz Julian Keil Thomas Hartmann Google Hannah Schulz Nathan Weisz Julian Keil Thomas Hartmann Google Scholar Hannah Schulz Nathan Weisz Julian Keil Thomas Hartmann PubMed Hannah Schulz Nathan Weisz Julian Keil Thomas Hartmann Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.