Active adjustment of the architectonics (structure) of motor units

Gekht, B. M.; Kasatkina, L. F.; Никитин, С.С.

doi:10.1007/bf00838845

Cited by 1 publication

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“…Our findings indicate that analysis of parameters characterizing the MC of MUPs is desirable in studies designed to detect changes in the morphofunctional Analysis of MC parameters thus yields new information that can modify to some extent our understanding of the morphofunctional organization of MUs in human skeletal muscle in various neuromuscular diseases [2,12,14].…”

Section: Resultsmentioning

confidence: 96%

Characteristics of motor unit potentials in human skeletal muscle during the denervation-reinnervation process

Kasatkina

Gekht

1996

Bull Exp Biol Med

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Traditionally measured parameters of motor unit potentials and parameters of the fast (spike) component of motor units were compared in the common extensor of fingers of 24 patients with chronic progressive diseases of motoneurons or their axons and 12 healthy subjects. The earliest signs of motor unit disorders are shown to be increased in the amplitude, duration, and number of turns in the spike (main) component of potentials. A correlation was found to exist between increases in muscle fiber density and in the number of turns. Analysis of the main component parameters indicates that both concentration of muscle fibers in the central zone of motor units and desynchronization of their activity occur in initial phases of the denervation-reinnervation process. Key Words: motor unit potentials; electromyography; compensatory innervationThe available methods of clinical electromyograplay enable investigators to study the morphofunctional organization of motor units (MUs) over time in various human diseases and to evaluate the course of denervation-reinnervation processes in muscles during the establishment of compensatory innervation.It was believed for a long time that the main parameter determining the state of a MU in the muscle is duration of the MU potential (MUP). In recent years, attempts have been made to enlarge the capabilities of clinical electromyography through a more detailed processing of the electromyographic signal recorded when the tension of the muscle under study is minimal [1,6,8,9].The purpose of the present investigation was to examine alterations in the spike (main) component of the MUPs during the development of a denervation-reinnervation process in patients with diseases Department of Human Neuromuscular Pathology, Russian Myasthenia Center; Institute of Genered Pathology and Pathophysiology, Russian Academy of Medicol Sciences, Moscow of motoneurons or their axons, given that these diseases can serve as convenient models for observing changes occurring in the muscle of interest over a relatively short period of time. MATERIALS AND METHODSElectromyographic examinations were performed with a Counterpoint electromyograph (Dantec Medical) using standard concentric needle electrodes with a leading-off surface of 0.07 mm 2 and an electrode with a 25 ~t diameter of the leading-off surface for recording muscle fiber potentials.In each muscle under study, parameters of at least 20 potentials of different MUs recorded by the conventional technique [4] were analyzed. Included in the analysis were MUPs after their 5-fold averaging (weighted MUPs) at a standard amplification (100 or 500 ~tV) and a ray run of 1-2 msec/cm. We evaluated the duration of the MUP and of its main component (MC), MUP and MC amplitudes, and the number of turns in the MUP and MC for potentials with amplitudes of at least 50 ~tV (Fig. 1).

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Section: Resultsmentioning

confidence: 96%