[Control of gaze and locomotion by spatial orientation].

We reported a new theory for daily vestibular functions which advocates top-down regulation of posture and gaze by supposing the coordinates in the brain. The hypothesis consists of three principles; first, the vestibular system is primarily a sensory system to detect spatial orientation; second, multisensory integrations reconstruct three-dimensional coordinates in the brain, which ascertain spatial orientation; third, daily behaviours like gazing or walking are controlled in a feed-forward manner by programming on the coordinates in the brain. The hypothesis was useful to understand strategic differences between active and passive movements, to distinct gaze control from ocular reflexes, to apply the rules of gaze control to posture control, and to clarify the mechanism to produce motion sickness.