Document Detail

Imperceptible electrical noise attenuates isometric plantar flexion force fluctuations with correlated reductions in postural sway.
MedLine Citation:
PMID:  22198530     Owner:  NLM     Status:  MEDLINE    
Optimal levels of noise stimulation have been shown to enhance the detection and transmission of neural signals thereby improving the performance of sensory and motor systems. The first series of experiments in the present study aimed to investigate whether subsensory electrical noise stimulation applied over the triceps surae (TS) in seated subjects decreases torque variability during a force-matching task of isometric plantar flexion and whether the same electrical noise stimulation decreases postural sway during quiet stance. Correlation tests were applied to investigate whether the noise-induced postural sway decrease is linearly predicted by the noise-induced torque variability decrease. A second series of experiments was conducted to investigate whether there are differences in torque variability between conditions in which the subsensory electrical noise is applied only to the TS, only to the tibialis anterior (TA) and to both TS and TA, during the force-matching task with seated subjects. Noise stimulation applied over the TS muscles caused a significant reduction in force variability during the maintained isometric force paradigm and also decreased postural oscillations during quiet stance. Moreover, there was a significant correlation between the reduction in force fluctuation and the decrease in postural sway with the electrical noise stimulation. This last result indicates that changes in plantar flexion force variability in response to a given subsensory random stimulation of the TS may provide an estimate of the variations in postural sway caused by the same subsensory stimulation of the TS. We suggest that the decreases in force variability and postural sway found here are due to stochastic resonance that causes an improved transmission of proprioceptive information. In the second series of experiments, the reduction in force variability found when noise was applied to the TA muscle alone did not reach statistical significance, suggesting that TS proprioception gives a better feedback to reduce force fluctuation in isometric plantar flexion conditions.
Fernando Henrique Magalhães; André Fabio Kohn
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2011-12-24
Journal Detail:
Title:  Experimental brain research     Volume:  217     ISSN:  1432-1106     ISO Abbreviation:  Exp Brain Res     Publication Date:  2012 Mar 
Date Detail:
Created Date:  2012-02-21     Completed Date:  2012-07-23     Revised Date:  2013-12-13    
Medline Journal Info:
Nlm Unique ID:  0043312     Medline TA:  Exp Brain Res     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  175-86     Citation Subset:  IM    
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MeSH Terms
Electromagnetic Phenomena
Muscle Contraction / physiology
Muscle, Skeletal / physiology
Postural Balance / physiology*
Posture / physiology*
Proprioception / physiology*

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