Movement cycles varied between subjects, and movement states within a movement cycle had different durations. Therefore, we first determined the time points when movement transitions occurred between different movement phases in each subject. Data were then aligned with these transition points to enable the averaging of dynamic PAC (dynPAC) values associated with movement transitions and to assess PAC changes across transitions between movement states. We subdivided PAC values of each movement cycle into five periods separated by four movement transition points defined at the level of the cortex (cortical transition points). The cortical transition points were defined to estimate the timing of the transitions at the cortical level with optimal accuracy. They were derived from the peripheral movement transition points which were measured by kinematic signals. In brief, we computed the cortical transition points by translocating the timing of the peripheral movement transition points, taking into account the mechanical delays, electromechanical delays and corticomuscular conduction time. The details for the determination of the transition points are described in the Supplemental Method section “Definition of 4 transition points of a movement cycle.”.
