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Science 13 July 1984:
Vol. 225. no. 4658, pp. 212 - 214
DOI: 10.1126/science.6729475

Articles

Science, Vol 225, Issue 4658, 212-214
Copyright © 1984 by American Association for the Advancement of Science


articles

Vestibulospinal reflexes as a function of microgravity

MF Reschke, DJ Anderson, and JL Homick

The idea that sustained microgravity will result in altered otolith input requiring a modification of postural control was explored by using the pathway that links the otolith organs and spinal motoneurons. Two related methods were used. First, the Hoffmann reflex was used to measure at specific times the excitability of the soleus-spinal motoneuron pool during a brief unexpected linear acceleration. Second, extensive dynamic postural testing with a moving platform was done before and after flight. The Hoffmann reflex amplitude, reflecting otolith-modulated motoneuron sensitivity, was low in flight after adaptation, and its postflight potentiation may have been dependent on rate of adaptation. The strength of inflight motion sickness symptoms was related to postflight Hoffmann reflex amplitude. Dynamic posture tests showed significant deviations from the results obtained before flight. The strategy used for balance on the moving platform was modified, and the behavior of the subjects suggested a decrease in awareness of the direction and magnitude of the motion.


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Spatial orientation in weightlessness and readaptation to earth's gravity.
L. Young, C. Oman, D. Watt, K. Money, and B. Lichtenberg (1984)
Science 225, 205-208
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