Abstract
The sensation of rotation derived from the semicircular canal system during a Coriolis stimulus, or cross-coupled rotation, was estimated by an mechanical approach by giving some hypotheses and simplifications on the semicircular canal system. By solving an equation of motion of the endolymph during a Coriolis stimulus with a moderate time course, the rotating angle of the endolymph was obtained, and the sensation of rotation derived from each semicircular canal was estimated. Then, the sensation was integrated in the whole semicircular canal system, which was considered to be composed of three orthogonal semicircular canals. The sensation of rotation derived from the semicircular canal system comes into conflict with those from the otolithic and somatosensory system. The conflict causes an illusion such that the head rotates vertically while keeping inclination at a constant tilt angle. The nauseogenic severity of motion sickness caused by a Coriolis stimulus is enhanced in accordance with the integrated angle of rotation perceived by the illusion.
