title: Analysis of posture and eye movement responses to Coriolis stimulation under 1 G and microgravity conditions.
abstract: To detect the effect of microgravity on vestibular responses, we conducted Coriolis stimulation experiments at 1 G and μ G. Five men with vision occluded were asked to tilt their head forward while rotating at 100 degrees/sec. Postural changes were recorded by a 3D linear accelerometer, and the distance of upper body movement was derived from recordings of linear acceleration. Eye movements were recorded by a CCD camera. For a second period after commencing head tilt, the upper body moved 10 cm in the direction of inertia input at 1 G, but it moved to the opposite direction at μ G, i.e., 4 cm in the direction of inertia force. Nystagmus peak slow-phase velocity immediately after head tilt and its attenuation process did not differ between 1 G and μ G. The strength of movement sensation and the severity of motion sickness were far weaker at μ G than at 1 G. It was concluded that inertia input is valid to induce postural and sensation responses only when the external reference is given Z axis by gravity. Vestibular ocular response may be maintained at μ G because the head reference is valid even after the external reference becomes arbitrary.
authors.affiliation: Department of Otolaryngology, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193, Japan. 167813@is.icc.u-tokai.ac.jp
authors.forename: Motoki
authors.initials: M
authors.lastname: Sekine
authors.forename: Masahiro
authors.initials: M
authors.lastname: Takahashi
authors.forename: Masahiro
authors.initials: M
authors.lastname: Iida
mesh_terms: D000054:Acceleration; D003312:Coriolis Force; D005133:Eye Movements / Q000502:physiology*; D006112:Gravitation; D006801:Humans; D007699:Kinesthesis / Q000502:physiology; D008297:Male; D009041:Motion Sickness; D011187:Posture / Q000502:physiology*; D012027:Reflex, Vestibulo-Ocular / Q000502:physiology*; D012399:Rotation; D014722:Vestibule, Labyrinth / Q000502:physiology; D014893:Weightlessness; D055815:Young Adult