Gravity as a Key Constraint on Sensorimotor Coordination

Sensing of the gravitation vertical is an essential component of the postural control system, and it is generally accepted that vestibular signals provide important, but not exclusive information about this important reference orientation. Less obvious is the need for vestibular information for tasks of visual orientation perception and sensorimotor coordination. In a recent study we tested patient suffering from vestibular disorders and compared their results with age-matched controls on a task of visual orientation matching. This comparison provides conclusive evidence that vestibular signal play a role in the multisensory perception of the vertical axis, a key constraint for the programming of arm movements and for arm-hand coordination.