Acceleration and Velocity Dissociate Temporal Phases of Postural Control in Rhesus Macaques

Maintaining balance requires transforming sensory signals about unexpected body motion into precisely timed motor commands. Progress in understanding this process has been limited because angular acceleration and velocity are inherently coupled during rotational perturbations. Here, using a rhesus macaque model, we dissociate these kinematic variables and show that they govern distinct temporal phases of postural control: angular acceleration determines short-latency (<100 ms) responses, whereas angular velocity shapes medium-latency (100-200 ms) adjustments. We further demonstrate axis-dependent postural strategies that parallel those observed in humans. Together, these findings resolve a longstanding confound in balance research and establish a primate framework that will enable future studies to link neural circuit activity to the biomechanics of postural control.