Time-varying Brain Potentials and Interhemispheric Coherences of Anterior and Posterior Regions during Repetitive Unimanual Finger Movements

Previous brain electrophysiological research has studied the interregionalconnectivity during the tapping task and found that inter-hemispheric alpha coherence wasmore significant under bimanual task conditions than that under unilateral conditions, butthe interregional connectivity situation in the unilateral tapping condition was not exploredclearly. We have designed a unilateral repetitive finger-tapping task to delineate the anteriorand posterior cortex contributions to unilateral finger movement. Sixteen right handedcollege students participated in this study. Event related potentials (ERPs) and the strengthof event related coherence (ERCoh) were analyzed to examine the antero-posterodominance of cortical activity in the phase of early visual process (75-120ms), pre-execution(175-260ms), execution (310-420ms) and post-execution (420-620ms). Results showed thatthe occipital (Oz, O1 and O2), frontal (Fz, F3, and F4), fronto-central (Fz, Cz, F3 and C3),and parietal regions were the most pronounced in the early visual, pre-execution, execution,and post-execution phases, respectively. Moreover, among four inter-hemispheric pairs onlythe Coh (C3 and C4) was significantly correlated to reaction time (RT) of tapping in theexecution phase. In conclusion, the aforementioned variability of electrophysiological data(ERPs and coherence) and the change of antero-postero regional dominance with timereflect the relative importance of different mechanisms in different phases. The mechanismsof visual processing, motor planning, motor execution and feedback reward wereoperational, respectively.