Motor Function
- DOI:
- 10.1093/med/9780190497774.003.0016
Voluntary movements are preceded by slow brain activity, visible in EEG as the Bereitschaftspotential (the readiness potential), and in MEG as the readiness field. These slow shifts can begin a few seconds before movement onset in the primary motor cortex and in the premotor areas. Cortex–muscle coherence refers to coupling between MEG/EEG signals and the surface EMG of a steadily contracted muscle; it typically occurs at around 20 Hz and implies an efferent drive from the cortex to the muscle. Corticokinematic coherence can be measured as the coupling between MEG/EEG signals and the acceleration or velocity of a rhythmically moving limb; it typically occurs are the movement frequency and its first harmonic. Coherence of MEG/EEG signals can be computed also with respect to other peripheral signals, such as the fundamental frequency of the voice measured with an accerometer above the subject’s throat.
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