Document Detail

Spectrally similar periodic and non-periodic optic flows evoke different postural sway responses.
MedLine Citation:
PMID:  16399514     Owner:  NLM     Status:  MEDLINE    
The present study investigated the effect of optic flow periodicity on postural sway. Head and center-of-pressure (COP) displacements in response to an oscillating full-field bullseye-and-checkerboard pattern were recorded in six healthy adults. Scene movement was driven by one of five signals: (1) 0.1 Hz sinusoid, (2) 0.3 Hz sinusoid, (3) 0.5 Hz sinusoid, (4) the periodic sum of these three sinusoids (PSUM), or (5) a non-periodic counterpart (NPSUM = 0.1+ pi/10 + 0.5 Hz). Sway response power at the various stimulus frequencies were compared: (1) among the three pure sinusoidal groups; and (2) between the two sum-of-sinusoid groups. Head and COP responses displayed similar spectral content, though sway magnitude was larger for the head. Sway responses to the moving scenes were significantly larger than those observed during quiet stance. Each sinusoidal moving scene evoked a strong response at the stimulus frequency, as well as increased sway at non-stimulus frequencies, primarily below 0.2 Hz. For the sum-of-sinusoids stimuli, both PSUM and NPSUM signals elicited sway responses at each of their component frequencies. The amplitudes of these responses were similar to one another at 0.1 and 0.3 Hz, but significantly different at 0.5 Hz, with PSUM responses on average four times larger than those for NPSUM. These findings indicate that spectrally similar periodic and non-periodic stimuli elicit quantitatively different sway responses. The observed behaviors may be due to postural sensitivity to the predictability of visual motion, or due to other nonlinear and/or time-varying mechanisms in the postural control system.
Mark C Musolino; Patrick J Loughlin; Patrick J Sparto; Mark S Redfern
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural    
Journal Detail:
Title:  Gait & posture     Volume:  23     ISSN:  0966-6362     ISO Abbreviation:  Gait Posture     Publication Date:  2006 Feb 
Date Detail:
Created Date:  2006-01-09     Completed Date:  2006-05-04     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  9416830     Medline TA:  Gait Posture     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  180-8     Citation Subset:  IM    
Department of Bioengineering, Eye and Ear Institute, 127, University of Pittsburgh, 203 Lothrop Street, PA 15213, USA.
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MeSH Terms
Head Movements / physiology
Motion Perception / physiology
Photic Stimulation*
Posture / physiology*
Proprioception / physiology
Visual Perception / physiology
Grant Support

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

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