DISCRIMINATION BETWEEN PHASE-LOCKED AND NON-PHASE-LOCKED EVENT-RELATED EEC ACTIVITY

Differentiation between phase-locked and non-phase-locked event-relate d EEG activity is an important task in the evaluation of event-related EEG activity. Event-related changes of EEG activity such as event-rel ated desynchronization (ERD) or event-related synchronization (ERS) ca n be quantified by either instantaneous band power or intertrial varia nce calculations. In the former case the ERD or ERS can be masked by a n event-related potential while in the fatter it is not. Examples from sensory stimulation and movement experiments, where the ERD (ERS) is calculated by both methods, are shown and discussed.