The control of multi-muscle systems: human jaw and hyoid movements

摘要: A model is presented of sagittal plane jaw and hyoid motion based on the ? motor control. The model, which implemented as a computer simulation, includes central neural control signals, position- velocity-dependent reflexes, reflex delays, muscle properties such dependence force length velocity. has seven muscles (or groups) attached to well separate bone dynamics. According movements result from changes in neurophysiological variables shift equilibrium state system. One variable an independent change membrane potential ?-motoneurons (MNs); this establishes threshold (?) at MN recruitment begins. Motor functions may be specified by various combinations ?s. combination ?s associated with level coactivation muscles. Others are motions specific degrees freedom. Using we study mapping between freedom corresponding individual We demonstrate that commands can defined involving linear produce essentially each four kinematic represented (jaw orientation, position, vertical horizontal position). These vectors space scaled magnitude. vector directions constant over jaw/hyoid workspace same any position. demonstration it not necessary adjust signals different parts supports idea nervous system need take explicit account musculo-skeletal geometry planning movements.