Lateralised EEG power and phase dynamics related to motor response execution

This study aimed to determine the underlying bases of single-trial electroencephalographic (EEG) activities of movement-related potential (MRP) and alpha-band event-related desynchronisation (alpha-ERD), both of which are cortical activities related to motor response execution because of their dependence on response time and laterality.

We 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.

Two lateralised EEG power and phase dynamics were observed: transient power decreases in alpha-band EEG (corresponding to alpha-ERD) and consistent contralateral phase lags of theta-band EEG.

alpha-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 theta-band additive EEG deflections.

Our results indicate that while both alpha-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.