Document Detail

Influence of handedness on motor unit discharge properties and force tremor.
MedLine Citation:
PMID:  7621929     Owner:  NLM     Status:  MEDLINE    
Discharge properties of motor units (MUs) in the first dorsal interosseous muscle (FDI) were studied in the dominant and non-dominant hands of six right-handed (RH) and six left-handed (LH) individuals. MU discharge rates and variability were similar in each hand in RH (186 MUs) and LH (160 MUs) subjects. MU synchronization was less prominent in the dominant hand of RH subjects, with 51% (45/88) of cross-correlograms of MU discharge having significant central peaks, compared with 81% (90/111) for the non-dominant hand. The strength of MU synchronization (expressed as the frequency of extra synchronous discharges above chance) was weaker in the dominant hand of right-handers (0.23 +/- 0.03 s-1 vs 0.39 +/- 0.03 s-1), and synchronous peaks from that hand were slightly broader. Four of six RH subjects had significant differences in synchronization between hands (weaker in dominant hand). In contrast, left-handers had similar incidence (80 vs 82%, n = 161) and strength (0.41 +/- 0.03 s-1 vs 0.37 +/- 0.03 s-1) of MU synchrony in dominant and non-dominant hands. No LH subject had a significant difference in synchronization between hands. Force tremor was quantified in each hand in the same subjects during isometric abduction of FDI at 0.5 N and 3.5 N, and directly correlated with the extent of MU synchronization in the muscle. Tremor root mean square amplitude was similar in dominant and non-dominant hands. Power spectral analysis of the tremor force revealed that the peak frequency in the power spectrum was not influenced by handedness, but power at the peak frequency was higher in the non-dominant hand of RH subjects. Correlations between MU discharge variability and synchrony with measures of tremor amplitude were weak. The reduced MU synchronization in the dominant hand of right-handers may reflect a more restricted distribution of direct projections from motor cortical neurons within the FDI motoneuron pool, or reduced excitability of the cortical neurons during the task. These differences in MU synchronization, however, had an insignificant influence on the magnitude of physiological tremor in the FDI.
J G Semmler; M A Nordstrom
Related Documents :
20664159 - Frequency spectrum analysis of finger photoplethysmographic waveform variability during...
1996689 - Characterization of responses of neonatal sinus and av nodes to critically timed, brief...
11295779 - Validation for tremor quantification of an electromagnetic tracking device.
15850129 - Parametric evaluation of heart rate variability during the menstrual cycle in young women.
12452419 - New sensor based on fibre optics for measurement of heart movement.
6641839 - Exploring the functional significance of physiological tremor: a biospectroscopic appro...
24642669 - Costimulation of the horizontal semicircular canal during skull vibrations in superior ...
1769919 - The effects of carbogen, carbon dioxide, and oxygen on noise-induced hearing loss.
7442919 - Behavioral effects of microwaves.
Publication Detail:
Type:  Clinical Trial; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Experimental brain research     Volume:  104     ISSN:  0014-4819     ISO Abbreviation:  Exp Brain Res     Publication Date:  1995  
Date Detail:
Created Date:  1995-08-31     Completed Date:  1995-08-31     Revised Date:  2013-12-13    
Medline Journal Info:
Nlm Unique ID:  0043312     Medline TA:  Exp Brain Res     Country:  GERMANY    
Other Details:
Languages:  eng     Pagination:  115-25     Citation Subset:  IM    
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Arm / innervation,  physiology
Cortical Synchronization
Functional Laterality / physiology*
Hand / innervation,  physiology
Isometric Contraction / physiology
Middle Aged
Motor Neurons / physiology*
Muscle, Skeletal / innervation,  physiology*
Tremor / physiopathology*

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

Previous Document:  Adapting to monocular vision: grasping with one eye.
Next Document:  Non-length-tuned cells in layers II/III and IV of the visual cortex: the effect of blockade of layer...