Event-related changes of band power and coherence: Methodology and interpretation

Event-related calculation of band power changes can be used to quantify eve nt-related desynchronization, event-related synchronization, and client-rel ated coherence (ERCoh). It is shown that in the case of a motor task especi ally, the ERCoh time course depends on the type of EEG derivation used, whe reby referenced EEG data can result in a bilateral coherence increase, alth ough both hemispheres generate independent sensorimotor rhythms. It is furt her shown that not only Rolandic mu rhythms but also central beta rhythms d isplay a lack of interhemispheric linear phase coupling.