scholarly journals Single motor unit firing rate after stroke is higher on the less-affected side during stable low-level voluntary contractions

2014 ◽  
Vol 8 ◽  
Author(s):  
Penelope A. McNulty ◽  
Gaven Lin ◽  
Catherine G. Doust
Keyword(s):  
Firing Rate ◽  
Motor Unit ◽  
Single Motor Unit ◽  
Single Motor ◽  
Low Level ◽  
Affected Side ◽  
Motor Unit Firing ◽  
Voluntary Contractions

scholarly journals MEASUREMENT OF SINGLE MOTOR UNIT FIRING RATE BY ARRAYED SURFACE ELECTRODE

Biomechanisms ◽  
1986 ◽  
Vol 8 (0) ◽  
pp. 99-107 ◽  
Author(s):  
Kenzo AKAZAWA ◽  
Kazushi MATSUNOKI ◽  
Katsuhiko FUJII ◽  
Masaki YOSHIDA
Keyword(s):  
Firing Rate ◽  
Motor Unit ◽  
Surface Electrode ◽  
Single Motor Unit ◽  
Single Motor ◽  
Motor Unit Firing

S53: Single motor unit firing changes in VEMPs

2014 ◽  
Vol 125 ◽  
pp. S11-S12
Author(s):  
S. Rosengren ◽  
K.P. Weber
Keyword(s):  
Motor Unit ◽  
Single Motor Unit ◽  
Single Motor ◽  
Motor Unit Firing

Nonlinear behaviour of human motoneurons

1995 ◽  
Vol 73 (1) ◽  
pp. 113-123 ◽  
Author(s):  
Louise Smith ◽  
Tao Zhong ◽  
Parveen Bawa
Keyword(s):  
Steady State ◽  
Firing Rate ◽  
Motor Unit ◽  
Human Subjects ◽  
Motor Units ◽  
Rate Of Change ◽  
Emg Activity ◽  
Nonlinear Behaviour ◽  
Single Motor Unit ◽  
Single Motor

When ramp-and-hold currents are injected into a motoneuron of an anesthetized cat, the motoneuron responds with a high initial firing rate (dynamic phase), which then adapts to a lower steady-state firing rate. The firing rates during the dynamic and the steady-state phases are linearly related to the rate of change and the magnitude of the injected current, respectively. In human subjects, where inputs to the motoneurons are not accessible, force parameters are used to describe motoneuron behaviour. Population responses of human motoneurons, measured in terms of gross electromyographic (EMG) activity, increase linearly with the magnitude and the rate of change of force. No study has attempted to examine the question of linearity of single motor units during the dynamic as well as the steady-state phases. The following study recorded single motor unit and EMG activities simultaneously from the flexor carpi radialis muscle in human subjects completing ramp-and-hold force trajectories. Although the results confirmed the linear relationship between EMG activities and the rate and magnitude of the force, a nonlinear activity pattern was observed between the single motor unit firing and the force parameters, suggesting that recruitment must be responsible for the linear behaviour of EMG activity. Comparisons of different background activity levels on the firing patterns of a given motor unit, as well as comparisons of two simultaneously recorded units, further supported nonlinear response patterns of single motor units.Key words: human, motoneurons, motor units, nonlinearity, force trajectory, repetitive firing.

Detection Algorithm for Single Motor Unit Firing in Surface EMG of the Trapezius Muscle

2010 ◽  
Vol 49 (05) ◽  
pp. 492-495
Author(s):  
W. Deburchgraeve ◽  
K. Van Damme ◽  
T. Adriaensen ◽  
A. Spaepen ◽  
S. Van Huffel ◽  
...  
Keyword(s):  
Motor Unit ◽  
Musculoskeletal Disorders ◽  
Trapezius Muscle ◽  
Energy Operator ◽  
Detection Algorithm ◽  
Mental Load ◽  
Single Motor Unit ◽  
Single Motor ◽  
Motor Unit Firing ◽  
Biofeedback System

Summary Background: Work-related musculoskeletal disorders (MSD) of the neck and the shoulders are a growing problem in society. An interesting pattern of spontaneous muscle activity, the firing of a single motor unit, in the trapezius muscle is observed during a laboratory study in a rest state or a state with a mental load. Objective: In this study, we report on the finding of the single motor unit firing and we present a detection algorithm to localize these single motor unit firings. Methods: A spike train detection algorithm, using a nonlinear energy operator and correlation, is presented to detect burst of highly correlated, high energetic spike-like segments. Results: This single motor unit was visible in 65% of the test subjects on one or both trapezius muscles although there was no change in posture of the test subjects. All the segments in the data that were determined as single motor unit firings were detected by the algorithm. Discussion: The physiological meaning of this firing pattern is a very low and subconscious contraction of the muscle. A long-term contraction could lead to the exhaustion of the muscle fibers, thus resulting in musculoskeletal disorders. The detection algorithm is able to localize this phenomenon in a sEMG measurement. The ability of detecting these firings is helpful in the research of its origin. Conclusion: The detection algorithm can be used to gain insight in the physiological origin of this phenomenon. In addition, the algorithm can also be used in a biofeedback system to warn the user for this undesired contraction to prevent MSD.

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