Document Detail

Crucial effects of weightlessness on human orientation.
MedLine Citation:
PMID:  8275265     Owner:  NLM     Status:  MEDLINE    
This contribution examines the consequences of two remarkable experiences of subjects in weightlessness, 1) the missing of sensations of trunk tilt and of the respective concomitant reflexes when the head is tilted with respect to the trunk, and 2) the persistence of a perception of "up" and "down," that is, of the polarity of the subjective vertical (SV) in the absence of, as well as in contradiction to, visual cues. The first disproves that the necessary head-to-trunk coordinate transformation be achieved by adding representations of the respective angles gained by utricles and neck receptors, but corroborates an extant model of cross-multiplication of utricular, saccular, and neck receptor components. The second indicates the existence of force-independent components in the determination of the SV. Although the number of subjects is still small and experimental conditions are not as homogeneous as desired, measurements and/or reports on the ground, in parabolic, and in space flight point to the decisive role of the saccular z-bias, that is, of a difference of the mean resting discharges of saccular units polarized in the rostrad and the caudad (+/- z-) direction.
H Mittelstaedt; S Glasauer
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Publication Detail:
Type:  Journal Article; Review    
Journal Detail:
Title:  Journal of vestibular research : equilibrium & orientation     Volume:  3     ISSN:  0957-4271     ISO Abbreviation:  J Vestib Res     Publication Date:  1993  
Date Detail:
Created Date:  1994-02-07     Completed Date:  1994-02-07     Revised Date:  2005-11-16    
Medline Journal Info:
Nlm Unique ID:  9104163     Medline TA:  J Vestib Res     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  307-14     Citation Subset:  IM; S    
Max-Planck-Institut für Verhaltensphysiologie, Seewiesen, Germany.
Space Flight Mission:
Flight Experiment; Mir Project; long duration; manned
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MeSH Terms
Muscles / physiology
Neck / physiology
Orientation / physiology*
Otolithic Membrane / physiology
Proprioception / physiology
Space Flight

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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