Synchronization of human motor units: possible roles of exercise and supraspinal reflexes

Electroencephalography and Clinical Neurophysiology
H S Milner-BrownR G Lee

Abstract

Some normal human subjects show definite synchronization of the motor units in hand muscles (i.e., the impulses from two or more motor units coincide in time more frequently than expected for independent random processes). Subjects who show synchronization tend to use their hands to exert large, brief forces, either in their work (e.g., manual laborers) or recreational activities (e.g., weightlifters). In this study all seven weightlifters examined showed a significant degree of synchronization. Furthermore, after 6 weeks of using the first dorsal interosseus muscle of the hand to exert maximal, voluntary contractions, the level of synchronization increased substantially in four control subjects, and the average level became significantly different from zero. Weightlifters also showed greater late reflex responses than control subjects, but no significant difference in earlier spinal reflexes. Two late reflex waves are described which probably involve fast pathways to and from motor cortes. We suggest that supraspinal connections from motor cortex directly to spinal motoneurons may be enhanced as a result of training to the point where they produce a significant synchronization of motor units during steady, voluntary contractions.

References

Jun 8, 2000·Muscle & Nerve·L R Robinson
May 1, 1994·Arthritis and Rheumatism·K K LyngbergB Danneskiold-Samsøe
Jan 1, 1995·European Journal of Applied Physiology and Occupational Physiology·P GermainJ F Marini
Apr 29, 1976·Journal of Mathematical Biology·M N Oğuztöreli, R B Stein
Jan 20, 1977·Biological cybernetics·H Hatze
Jan 1, 1982·Biological cybernetics·W KilmerV Congdon
Jan 1, 1991·European Journal of Applied Physiology and Occupational Physiology·C PérotI Mora
Jan 1, 1976·Biological cybernetics·R B Stein, M N Oğuztöreli
Jan 1, 1996·European Journal of Applied Physiology and Occupational Physiology·Y Koryak
Jan 1, 1990·European Journal of Applied Physiology and Occupational Physiology·K IshidaK Itoh
Jan 1, 1990·European Journal of Applied Physiology and Occupational Physiology·I TabataM Miyashita
Jan 1, 1986·European Archives of Psychiatry and Neurological Sciences·D ClausH J Dietrich
Feb 1, 1980·European Journal of Applied Physiology and Occupational Physiology·J D MacDougallJ R Sutton
May 18, 1979·European Journal of Applied Physiology and Occupational Physiology·G Kamen
Jan 1, 1980·European Journal of Applied Physiology and Occupational Physiology·S LewisW Haskell
Jan 1, 1984·European Journal of Applied Physiology and Occupational Physiology·C BoscoR Pozzo
Jan 1, 1983·European Journal of Applied Physiology and Occupational Physiology·H Kanehisa, M Miyashita
Jan 1, 1984·European Journal of Applied Physiology and Occupational Physiology·M J McDonagh, C T Davies
Jan 1, 1995·European Journal of Applied Physiology and Occupational Physiology·C BoscoC Tranquilli
Jan 1, 1992·European Journal of Applied Physiology and Occupational Physiology·N P Gleeson, T H Mercer
Jan 1, 1986·European Journal of Applied Physiology and Occupational Physiology·K Häkkinen, P V Komi
Jan 1, 1994·European Journal of Applied Physiology and Occupational Physiology·C BoscoG S Roi
Jan 1, 1983·European Journal of Applied Physiology and Occupational Physiology·M E HoustonD A Ranney
Sep 1, 1979·Experimental Brain Research·M McCormack, B Dubrovsky
Jan 1, 1989·European Journal of Applied Physiology and Occupational Physiology·M V NariciP Cerretelli
Jan 1, 1986·Medical & Biological Engineering & Computing·G F InbarH Kranz
Dec 16, 2004·Experimental Brain Research·Benjamin K BarryRichard G Carson
Jan 2, 2008·Aesthetic Plastic Surgery·L A DessyN Scuderi
May 27, 2005·European Journal of Applied Physiology·Andreas HoltermannGertjan Ettema
Apr 10, 2009·European Journal of Applied Physiology·Olivier GirardGrégoire Millet
Sep 18, 2009·European Journal of Applied Physiology·Murat KarabulutMichael G Bemben
Sep 23, 2009·European Journal of Applied Physiology·T I ArabadzhievG V Dimitrov
Jun 1, 2010·European Journal of Applied Physiology·Marius S FimlandJan Hoff
Aug 3, 2010·European Journal of Applied Physiology·Lena NorrbrandP A Tesch
Nov 11, 2010·European Journal of Applied Physiology·Pierpaolo IodiceRaoul Saggini
Jan 1, 1976·Electroencephalography and Clinical Neurophysiology·V DietzH J Freund

Citations

Jun 1, 1972·Electroencephalography and Clinical Neurophysiology·R Q Cracco
Oct 1, 1973·Electroencephalography and Clinical Neurophysiology·R Q Cracco
Nov 1, 1973·The Journal of Physiology·R E Burke, P Tsairis
Jul 1, 1968·Electroencephalography and Clinical Neurophysiology·R S Person, L P Kudina
Oct 1, 1973·Journal of the Neurological Sciences·E Kugelberg
Apr 1, 1974·Canadian Journal of Physiology and Pharmacology·Y C WongJ T Murphy
Sep 1, 1970·Biophysical Journal·G P MooreH Levitan
Apr 1, 1973·The Journal of Physiology·H S Milner-BrownR Yemm
May 20, 1969·Proceedings of the Royal Society of London. Series B, Containing Papers of a Biological Character·C G Phillips
May 17, 1974·Brain Research·J T MurphyH C Kwan
Jul 21, 1972·Nature·C D MarsdenH B Morton
Jan 1, 1973·The Journal of Physiology·H S Milner-BrownR Yemm
Jun 1, 1974·Journal of Neurology, Neurosurgery, and Psychiatry·H S Milner-BrownR G Lee
Jun 1, 1966·Journal of Neurology, Neurosurgery, and Psychiatry·J G McLeod, S H Wray
Jan 1, 1972·Archiv für Psychiatrie und Nervenkrankheiten·K Meier-EwertJ Dahm
Sep 1, 1971·The Journal of Physiology·C G PhillipsM Wiesendanger
Dec 1, 1971·Journal of Neurology, Neurosurgery, and Psychiatry·A R UptonR E Sica
Oct 1, 1970·Acta Oto-laryngologica·T TokitaK Kato
Nov 1, 1970·Acta Oto-laryngologica·M N Kotby, L K Haugen
Aug 27, 1954·The Journal of Physiology·B BIGLAND, O C LIPPOLD
Jul 1, 1962·The Journal of Physiology·A TAYLOR
Aug 15, 1964·The Japanese Journal of Physiology·M SHIMAMURAB FUJIMORI
Nov 1, 1950·Electroencephalography and Clinical Neurophysiology·F BUCHTHAL, A MADSEN
Feb 1, 1949·Archives of Neurology and Psychiatry·D DENNY-BROWN
Mar 1, 1947·Brain : a Journal of Neurology·E D ADRIAN

Related Concepts

Examination of Reflexes
Surface Electromyography
Hand
Biochemical Pathway
Exertion
Muscle Structure of Hand
Contraction (Finding)
Motor Neurons
Physical Fitness
Mutism

Trending Feeds

COVID-19

Coronaviruses encompass a large family of viruses that cause the common cold as well as more serious diseases, such as the ongoing outbreak of coronavirus disease 2019 (COVID-19; formally known as 2019-nCoV). Coronaviruses can spread from animals to humans; symptoms include fever, cough, shortness of breath, and breathing difficulties; in more severe cases, infection can lead to death. This feed covers recent research on COVID-19.

Sexual Dimorphism in Neurodegeneration

There exist sex differences in neurodevelopmental and neurodegenerative disorders. For instance, multiple sclerosis is more common in women, whereas Parkinson’s disease is more common in men. Here is the latest research on sexual dimorphism in neurodegeneration

HLA Genetic Variation

HLA genetic variation has been found to confer risk for a wide variety of diseases. Identifying these associations and understanding their molecular mechanisms is ongoing and holds promise for the development of therapeutics. Find the latest research on HLA genetic variation here.

Super-resolution Microscopy

Super-resolution microscopy is the term commonly given to fluorescence microscopy techniques with resolutions that are not limited by the diffraction of light. Here are the latest discoveries pertaining to super-resolution microscopy.

Genetic Screens in iPSC-derived Brain Cells

Genetic screening is a critical tool that can be employed to define and understand gene function and interaction. This feed focuses on genetic screens conducted using induced pluripotent stem cell (iPSC)-derived brain cells.

Brain Lower Grade Glioma

Low grade gliomas in the brain form from oligodendrocytes and astrocytes and are the slowest-growing glioma in adults. Discover the latest research on these brain tumors here.

CD4/CD8 Signaling

Cluster of differentiation 4 and 8 (CD8 and CD8) are glycoproteins founds on the surface of immune cells. Here is the latest research on their role in cell signaling pathways.

Alignment-free Sequence Analysis Tools

Alignment-free sequence analyses have been applied to problems ranging from whole-genome phylogeny to the classification of protein families, identification of horizontally transferred genes, and detection of recombined sequences. Here is the latest research.

Chronic Fatigue Syndrome

Chronic fatigue syndrome is a disease characterized by unexplained disabling fatigue; the pathology of which is incompletely understood. Discover the latest research on chronic fatigue syndrome here.