Study of Age Changes in the Motor Units of the First Dorsal Interosseous Muscle in Man

Gerontology ◽  
1988 ◽  
Vol 34 (3) ◽  
pp. 115-119 ◽  
Author(s):  
J.P. Newton ◽  
R. Yemm ◽  
M.J.N. McDonagh
Keyword(s):  
Motor Units ◽  
First Dorsal Interosseous ◽  
Age Changes ◽  
First Dorsal Interosseous Muscle ◽  
Dorsal Interosseous Muscle

scholarly journals Muscle fatigue increases beta-band coherence between the firing times of simultaneously active motor units in the first dorsal interosseous muscle

2016 ◽  
Vol 115 (6) ◽  
pp. 2830-2839 ◽  
Author(s):  
Lara McManus ◽  
Xiaogang Hu ◽  
William Z. Rymer ◽  
Nina L. Suresh ◽  
Madeleine M. Lowery
Keyword(s):  
Motor Units ◽  
Surface Emg ◽  
Relative Increase ◽  
Wavelet Coherence ◽  
First Dorsal Interosseous ◽  
Beta Band ◽  
Indirect Measures ◽  
First Dorsal Interosseous Muscle ◽  
Active Motor ◽  
Dorsal Interosseous Muscle

Synchronization between the firing times of simultaneously active motor units (MUs) is generally assumed to increase during fatiguing contractions. To date, however, estimates of MU synchronization have relied on indirect measures, derived from surface electromyographic (EMG) interference signals. This study used intramuscular coherence to investigate the correlation between MU discharges in the first dorsal interosseous muscle during and immediately following a submaximal fatiguing contraction, and after rest. Coherence between composite MU spike trains, derived from decomposed surface EMG, were examined in the delta (1–4 Hz), alpha (8–12 Hz), beta (15–30 Hz), and gamma (30–60 Hz) frequency band ranges. A significant increase in MU coherence was observed in the delta, alpha, and beta frequency bands postfatigue. In addition, wavelet coherence revealed a tendency for delta-, alpha-, and beta-band coherence to increase during the fatiguing contraction, with subjects exhibiting low initial coherence values displaying the greatest relative increase. This was accompanied by an increase in MU short-term synchronization and a decline in mean firing rate of the majority of MUs detected during the sustained contraction. A model of the motoneuron pool and surface EMG was used to investigate factors influencing the coherence estimate. Simulation results indicated that changes in motoneuron inhibition and firing rates alone could not directly account for increased beta-band coherence postfatigue. The observed increase is, therefore, more likely to arise from an increase in the strength of correlated inputs to MUs as the muscle fatigues.

Motor-unit recruitment in human first dorsal interosseous muscle for static contractions in three different directions

1986 ◽  
Vol 55 (5) ◽  
pp. 1017-1029 ◽  
Author(s):  
C. K. Thomas ◽  
B. H. Ross ◽  
R. B. Stein
Keyword(s):  
Motor Unit ◽  
Index Finger ◽  
Rank Order ◽  
Motor Units ◽  
Motor Unit Recruitment ◽  
First Dorsal Interosseous ◽  
First Dorsal Interosseous Muscle ◽  
Contraction Times ◽  
Static Contractions ◽  
Dorsal Interosseous Muscle

Spike-triggered averaging was used to extract the twitch tensions and contraction times of 144 motor units from the first dorsal interosseous muscle of four subjects for three different directions of static contraction: abduction of the index finger, flexion of the index finger, and adduction of the thumb coupled with flexion of the index finger (hereafter referred to as adduction). Although the twitch tensions were generally largest for the abduction contraction, all units contributed tension to all three directions of contraction. A linear correlation was found for twitch tensions of motor units for the three directions of static contractions. Linear correlations were also found between twitch tension and threshold force of these motor units for each direction, which suggests that an orderly pattern of recruitment, according to increasing twitch size, adequately describes the function of human first dorsal interosseous muscle for all contraction directions. No clear evidence was found for separate groups of motor units in the muscle that were selectively activated for the different tasks. Rank order of recruitment for motor units in the three directions of contraction was correlated, but was not identical. The scatter in our data is discussed in relation to earlier reports of altered motor-unit recruitment during different movements.

Restoration of the first dorsal interosseous muscle

2021 ◽  
Author(s):  
C. Jaloux ◽  
A. Mayoly ◽  
C. Philandrianos ◽  
E. Bougie ◽  
R. Legré
Keyword(s):  
First Dorsal Interosseous ◽  
First Dorsal Interosseous Muscle ◽  
Dorsal Interosseous Muscle
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