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MODELING VESTIBULAR EFFECTS OF ARTIFICIAL GRAVITY BY GONDOLA CENTRIFUGATION IN MICE.  T.M. Coffee¹, S.A. Gill⁴, E.B. Wagner^1,3, M.J. Theis¹, S. Tsikata², I.M. Bernal¹, A.W. Bryan³, D.M. Merfeld³.  ¹Department of Aeronautics and Astronautics, ²Department of Mechanical Engineering, and ³Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge.  ⁴International Space University, Strasbourg, France.

   More extensive use of rotational spaceflight research platforms is planned for the International Space Station and free-flying biosatellites in coming years. While long-radius platforms pose inherent practical difficulties, short-radius platforms cause abnormal vestibular effects in mammals due to inertial forces in rotating reference frames.
   In preparation for the artificial gravity experiment to be flown aboard the Mars Gravity Biosatellite, we have developed a ground-based gondola centrifuge for mice to assess these effects in short-radius rotation. In order to analyze the results from this platform, we have developed a mathematical model of the physical environment it provides to rodent subjects. The model accounts for three categories of effects: static ideal effects as experienced by a stationary body on an ideal centrifuge; static anisotropic effects as experienced by a stationary body removed from the platform's ideal point; and dynamic effects due to animal movement within the platform. We assess the practical implications of the model based on current understanding of processing and adaptation by the mammalian vestibular system.
   Based on the above analysis, we conclude that: (1) the gondola centrifuge should provide a reasonable indicator of static ideal vestibular adaptations, but a mechanism for orientation correction will be required to interpret AG observations; (2) static anisotropic factors should not substantially affect behavioral results; (3) the platform does not provide useful information on potentially debilitating dynamic effects. These results should be considered in planning and assessment of behavioral data for future short-radius AG studies.

(Supported by the NASA Ames Fundamental Space Biology Division.)