Asymmetric spatiotemporal patterns of event-related desynchronization preceding voluntary sequential finger movements: a high-resolution EEG study.

OBJECTIVE: To study spatiotemporal patterns of event-related desynchronization (ERD) preceding voluntary sequential finger movements performed with dominant right hand and nondominant left hand. METHODS: Nine subjects performed self-paced movements consisting of three key strokes with either hand. Subjects randomized the laterality and timing of movements. Electroencephalogram (EEG) was recorded from 122 channels. Reference-free EEG power measurements in the beta band were calculated off-line. RESULTS: During motor preparation (-2 to -0.5s with respect to movement onset), contralateral preponderance of event-related desynchronization (ERD) (lateralized power) was only observed during right hand finger movements, whereas ERD during left hand finger movements was bilateral. CONCLUSIONS: For right-handers, activation on the left hemisphere during left hand movements is greater than that on the right hemisphere during right hand movements. SIGNIFICANCE: We provide further evidence for motor dominance of the left hemisphere in early period of motor preparation for complex sequential finger movements.