Lateralised EEG power and phase dynamics related to motor response execution

ObjectiveThis study aimed to determine the underlying bases of single-trial electroencephalographic (EEG) activities of movement-related potential (MRP) and α-band event-related desynchronisation (α-ERD), both of which are cortical activities related to motor response execution because of their dependence on response time and laterality.MethodsWe compared stimulus- and response-triggered EEG power and phase dynamics ipsilateral and contralateral to the response hand in Go trials during visual Go/NoGo reaction time tasks.ResultsTwo lateralised EEG power and phase dynamics were observed: transient power decreases in α-band EEG (corresponding to α-ERD) and consistent contralateral phase lags of θ-band EEG.Conclusionsα-ERD around the response onset is not substantially reflected in the MRP waveforms mainly because of phase inconsistency. Lateralised MRP waveforms around the response onset are mainly attributed to consistent contralateral phase lags in θ-band additive EEG deflections.SignificanceOur results indicate that while both α-ERD and lateralised MRP are related to motor response execution, they reflect separate cortical activities. Analysis of EEG power and phase dynamics can help in elucidating the detailed underlying bases of cortical activities.