Somatosensory motion after-effect following earth-horizontal rotation about the Z-axis: a new illusion.

During rotation about the Z-axos while recumbent one is exposed to a changing pattern of pressure cues over the body surface. If the body is only loosely padded in the experimental apparatus, then apparent motion of part of the body surface may be experienced sometime after rotation has been terminated. This somatosensory motion aftereffect of opposite sign is temporarily abolished if one looks at the affected body area, but is again re-experienced when the gaze is shifted elswhere. The similarity of this motion aftereffect to those contingent on vestibular and visual stimulation is discussed.