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M.I.T./Canadian vestibular experiments on the Spacelab-1 mission. III - Effects of prolonged weightlessness on a human otolith-spinal reflexReflex responses that depend on human otolith organ sensitivity were measured before, during and after a 10 day space flight. Otolith-spinal reflexes were elicited by means of sudden, unexpected falls. In weightlessness, 'falls' were achieved using elastic cords running from a torso harness to the floor. Electromyographic (EMG) activity was recorded from gastrocnemius-soleus. The EMG response occurring in the first 100-120 ms of a fall, considered to be predominantly otolith-spinal in origin, decreased in amplitude immediately upon entering weightlessness, and continued to decline throughout the flight, especially during the first two mission days. The response returned to normal before the first post-flight testing session. The results suggest that information coming from the otolith organs is gradually ignored by the nervous system during prolonged space flight, although the possibility that otolith-spinal reflexes are decreased independent of other otolith output pathways cannot by ruled out.
Document ID
19870040072
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Watt, D. G. D.
(McGill Univ. Montreal Quebec, Canada)
Money, K. E.
(McGill University Montreal, Canada)
Tomi, L. M.
(Defence and Civil Institute of Environmental Medicine Downsview, Canada)
Date Acquired
August 13, 2013
Publication Date
January 1, 1986
Publication Information
Publication: Experimental Brain Research
Volume: 64
ISSN: 0014-4819
Subject Category
Aerospace Medicine
Accession Number
87A27346
Funding Number(s)
CONTRACT_GRANT: MRC-MA-5837
CONTRACT_GRANT: MRC-SP-10
CONTRACT_GRANT: MRC-TG-32
Distribution Limits
Public
Copyright
Other

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