Document Detail

Coupling of fingertip somatosensory information to head and body sway.
MedLine Citation:
PMID:  9108214     Owner:  NLM     Status:  MEDLINE    
Light touch contact of a fingertip with a stationary surface can provide orientation information that enhances control of upright stance. Slight changes in contact force at the fingertip provide sensory cues about the direction of body sway, allowing attenuation of sway. In the present study, we asked to which extent somatosensory cues are part of the postural control system, that is, which sensory signal supports this coupling? We investigated postural control not only when the contact surface was stationary, but also when it was moving rhythmically (from 0.1 to 0.5 Hz). In doing so, we brought somatosensory cues from the hand into conflict with other parts of the postural control system. Our focus was the temporal relationship between body sway and the contact surface. Postural sway was highly coherent with contact surface motion. Head and body sway assumed the frequency of the moving contact surface at all test frequencies. To account for these results, a simple model was formulated by approximating the postural control system as a second-order linear dynamical system. The influence of the touch stimulus was captured as the difference between the velocity of the contact surface and the velocity of body sway, multiplied by a coupling constant. Comparison of empirical results (relative phase, coherence, and gain) with model predictions supports the hypothesis of coupling between body sway and touch cues through the velocity of the somatosensory stimulus at the fingertip. One subject, who perceived movement of the touch surface, demonstrated weaker coupling than other subjects, suggesting that cognitive mechanisms introduce flexibility into the postural control scheme.
J J Jeka; G Schöner; T Dijkstra; P Ribeiro; J R Lackner
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Experimental brain research     Volume:  113     ISSN:  0014-4819     ISO Abbreviation:  Exp Brain Res     Publication Date:  1997 Mar 
Date Detail:
Created Date:  1997-06-27     Completed Date:  1997-06-27     Revised Date:  2013-12-13    
Medline Journal Info:
Nlm Unique ID:  0043312     Medline TA:  Exp Brain Res     Country:  GERMANY    
Other Details:
Languages:  eng     Pagination:  475-83     Citation Subset:  IM; S    
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MeSH Terms
Fingers / physiology*
Head / physiology*
Movement / physiology*
Posture / physiology*
Somatosensory Cortex / physiology*
Grant Support
J R Lackner / Brandeis U, Waltham, MA

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