Patterns of vestibular and neck responses and their interaction: a comparison between cat cortical neurons and human psychophysics.

The present study provides evidence that during whole-body rotation and during isolated rotation of either the head or the trunk, essentially the same processing of labyrinthine and neck afferent inputs takes place in neurons of the cat's ASS cortex and in humans who try to distinguish these stimulus conditions. This processing includes, among others (1) measurement of angular velocity and displacement during labyrinthine stimulation (whole-body rotation); (2) indication of trunk rotation as well as of an apparent head rotation in the opposite direction during neck stimulation (isolated trunk rotation); and (3) subtraction as well as addition of labyrinthine and neck afferent inputs during combined stimulation (isolated head rotation). Subtraction provides a basis for the discrimination between whole-body rotation and isolated head rotation; addition may optimize the indication of movement and position of the head in space.