The vestibulospinal system and postural regulation in man.

Upright posture in humans represents a giant step phylogenetically speaking. But upright posture demands refined mechanisms for static and dynamic postural equilibrium that are initiated by the concurrence of visual and proprioceptive impulses from the muscles of the legs and the labyrinth. The static labyrinth and Deiter's nucleus via the LVST seem to be the main centers responsible for static equilibrium. Its basic neurophysiological mechanism has been analyzed by the study of stretch reflexes, which permits a semiquantitative evaluation of the function of the static labyrinth. The cerebellum appears as the main control center of the proprioceptive system in relation to dynamic equilibrium.