Further insight into the role of PAC in motor control was provided by the detailed analysis of its dynamic modulation across a movement cycle (dynPAC). When controls performed the pressing task, PAC exhibited a brief peak followed by a decline during the initial press phase and a subsequent rebound while the index finger maintained constant pressure. Of note, dynPAC showed a similar pattern during the initial releasing phase of the pressing task and around the finger extension onset in the slow tapping task (decrease following a brief peak, followed by a rebound). These findings in healthy controls suggest that PAC decrease is not merely associated with initiating a movement. Rather, there appears to be a characteristic PAC motif (brief peak → decrease → rebound) that signals a change in movement states. This phenomenon resembles the preparatory neuronal activity in the dynamic systems theory of motor control (21). According to this theory, preparatory activity brings the dynamic state of the neuronal population through state-space rotations to an initial value. This process, which is characterized by brief cortical oscillatory activity (20), ensures
