Mechanismen und Funktion der EEG-EMG-Synchronisation im motorischen System des Menschen bei willkürlichen und unwillkürlichen Bewegungen
Final Report Abstract
Our findings obtained during this last grant period shed more light on the oscillatory cortical motor control of low static and dynamic isometric forces as are most of the forces in everyday life. For this purpose, we investigated the synchronization between cortical motor areas and the active muscles as measured by the EEG-EMG corticomuscular coherence (CMC). The correlation found between beta-range CMC during static force and the computational load of the preceding isometric motor engagement in dynamic forces suggests beta-range CMC provides a functional corticospinal gateway for steady force-related processing that can override cortical states tuned to dynamic force. The modulation of corticospinal beta-range coherence might thus ensure comparable precision of static force in various motor contexts. The beta-range CMC may be a correlate of the deletion of motor memory of the preceding motor state. Further studies have to be designed to provide evidences for this. Further, our results favour the view that the function of beta-range CMC is not specific for low-level static forces only. The sensorimotor system may resort to stronger and also broader beta-range CMC to generate stable corticospinal interaction during increased force level, as well as when compensating for periodically modulated dynamic forces. This finding reemphasizes the importance of the beta-range CMC in sensorimotor integration. During this grant period we succeeded in answering the question raised in many laboratories why CMC can not be recorded in all subjects investigated: we presented evidence that this is due to the fact that individuals may fall into two different groups in terms of oscillatory motor control: those with higher and those with lower cortical “motor efficiency”. We defined the cortical “motor efficiency” as cortical activation as reflected in the task-related desynchronization for the same performance. Subjects with lower “motor efficiency” need stronger cortical activation for the same performance as the subjects with higher “motor efficiency”. The group with lower “motor efficiency” presents CMC only after learning. The present findings contribute significantly to the neurophysiology of a motor Brain-Computer-Interface based on electroencephalography.
Publications
- (2009) Beta-range EEG-EMG coherence with isometric compensation for increasing modulated low-level forces J. Neurophysiol. 102:1115-1120
Chakarov, V., Naranjo,JR, Schulte-Mönting, J., Omlor, W., Huethe, F., Kristeva, R.
- (2010) Corticospinal interaction during isometric compensation for modulated forces with different frequencies. BMC Neurosci. 2010 Dec 31;11:157
Naranjo JR, Wang X, Schulte-Mönting J, Huethe F, Maurer C, Hepp-Reymond MC, Kristeva R
- (2011) Corticomuscular coherence reflects interindividual differences in the state of the corticomuscular network during low-level static and dynamic forces. Cereb Cortex. 2011 Jun 17
Mendez-Balbuena I., Huethe F., Schulte-Mönting J., Leonhart R., Manjarrez E., Kristeva R.
- (2011) Corticospinal beta-range coherence is highly dependent on the pre-stationary motor state. J Neurosci. 2011 Jun 1;31(22):8037-45
Omlor W., Patino L., Mendez-Balbuena I., Schulte-Mönting J., Kristeva R.
