Abstract
Mu suppression is the attenuation of EEG power in the alpha frequency range (8-12 Hz) while executing or observing a motor action. Whereas typically observed at central scalp sites, there are diverging reports about the extent of the attenuation over the cortical mantle, its exact frequency range and the specificity of this phenomenon. We investigated the modulation of EEG oscillations in frequency-bands between 4 to 12 Hz at frontal, central, parietal and occipital sites during the execution of manual movements and during observation of similar actions from allocentric (i.e., facing the actor) and egocentric (i.e., seeing the actor from behind) viewpoints. Suppression was determined relative to observation of a non-biological movement. Action observation elicited greater suppression in the lower (8-10 Hz) compared to the higher mu range (10-12 Hz), and greater suppression in the entire range (4-12 Hz) at frontal and central sites compared to parietal and occipital sites. In addition, suppression tended to be greater during observation of a motor action from allocentric compared to egocentric viewpoints. During execution of movement, suppression of the EEG occurred primarily in the higher alpha range and was absent at occipital sites. In the theta range (4-8 Hz), the EEG amplitude was suppressed during action observation and execution. The results suggest a functional distinction between modulation of mu and alpha rhythms, and between the higher and lower ranges of the mu rhythms. The activity of the presumed human mirror-neuron system seems primarily evident in the lower mu range and in the theta range.
Original language | English |
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Pages (from-to) | 43-57 |
Number of pages | 15 |
Journal | Brain Research |
Volume | 1509 |
DOIs | |
State | Published - 6 May 2013 |
Bibliographical note
Funding Information:This research project was carried out by the first author in partial fulfillment of the requirements for the PhD degree at the Sackler Faculty of Medicine - Tel Aviv University, under the supervision of Shlomo Bentin, Dario G. Liebermann and Nachum Soroker. We dedicate the paper in memory of Professor Shlomo Bentin, who recently passed away in a tragic accident. We wish to thank the participants for their cooperation in the experiment. This research was partially funded by the Legacy Foundation granted through the Loewenstein Rehabilitation Hospital , the Steyer Family Endowment through the Stanley Steyer School of Health Professions of the Sackler Faculty of Medicine - Tel Aviv University and the Israeli Ministry of Health no. 3-00000-7772.
Keywords
- Alpha-rhythm
- EEG
- Mirror-neuron
- Mu-rhythm
- Perception-action cycle