Changes in functional coupling patterns during bimanual task performance.

Functional interaction between cortical areas may involve synchronization of activities, manifest as coherence between EEG signals. However, although EEG-EEG coherence changes when motor tasks are compared to each other or rest, there is little evidence that coherence is modulated within an action. To address this issue we used a bimanual drawer-opening task necessitating asymmetrical hand actions and comprising distinct movement phases. Pronounced modulations in EEG-EEG coherence in the beta band (>12-24 Hz) occurred with movement phase. Differences in coherence due to a switch in role of the hands were mainly observed in the alpha band (8-12 Hz). These findings suggest that inter-regional synchronization changes dynamically across task execution in line with behavioral performance.