Single Fiber Electromyography

2016 ◽  
pp. 465-483
Author(s):  
Brian A. Crum ◽  
C. Michel Harper
Keyword(s):  
Neuromuscular Junction ◽  
Neuromuscular Transmission ◽  
Muscle Fibers ◽  
Single Fiber ◽  
Recording Equipment ◽  
Fiber Density ◽  
Individual Muscle ◽  
Technical Factors ◽  
Normal Fiber

Single fiber electromyography (SFEMG) is an advanced neurophysiological technique that is primarily used to assess the neuromuscular junction and disorders impairing adequate neuromuscular transmission. SFEMG measurements that are most useful clinically include jitter and blocking, which are quantitative and sensitive measures of neuromuscular transmission inefficiency; and abnormalities in these occur early in the course of diseases, often when standard electrodiagnostic studies are normal. Fiber density assesses the density of individual muscle fibers in each region of the muscle and is increased in a nonspecific manner in most neurogenic and myopathic disorders. SFEMG requires specialized recording equipment, which is used in the collection, display, analysis, reporting, and archiving of SFEMG data. Knowledge of technical limitations and potential pitfalls is vital in acquisition and analysis of SFEMG data. This chapter will review the concepts, methods, measurements, and technical factors related to single fiber EMG. SFEMG findings in various diseases will be reviewed.

POSTSYNAPTIC EFFECTS OF HC-3 AT THE NEUROMUSCULAR JUNCTION OF THE FROG

1961 ◽  
Vol 39 (2) ◽  
pp. 343-349 ◽  
Author(s):  
A. R. Martin ◽  
R. K. Orkand
Keyword(s):  
Neuromuscular Junction ◽  
Intracellular Recording ◽  
Neuromuscular Transmission ◽  
Muscle Fibers ◽  
Marked Change ◽  
Single Muscle ◽  
End Plate ◽  
Quantum Content ◽  
Iontophoretic Application

Intracellular recording from single muscle fibers has been used to study the effects of hemicholinium No. 3 (HC-3) on neuromuscular transmission in the excised m. ext. l. dig. IV of the frog. Concentrations of HC-3 greater than 10−5 M decreased the amplitude of the end-plate potentials (e.p.p.'s) and the magnitude of the depolarization produced by iontophoretic application of acetylcholine. Neither a decrease in e.p.p. quantum content nor depolarization of the end plate accompanied the decreased e.p.p. amplitude. The duration of the potential produced by the application of ACh was increased and the falling phase of the e.p.p. prolonged. 10−4 M HC-3 produced a marked change in the shape of the e.p.p., the effect being similar to that produced by procaine.

scholarly journals Presynaptic Paraneoplastic Disorders of the Neuromuscular Junction: An Update

2021 ◽  
Vol 11 (8) ◽  
pp. 1035
Author(s):  
Maria Pia Giannoccaro ◽  
Patrizia Avoni ◽  
Rocco Liguori
Keyword(s):  
Potassium Channels ◽  
Neuromuscular Junction ◽  
Calcium Channels ◽  
Myasthenia Gravis ◽  
Neuromuscular Transmission ◽  
Voltage Gated ◽  
Voltage Gated Calcium Channels ◽  
Immune Mediated ◽  
Recent Developments ◽  
Myasthenic Syndrome

The neuromuscular junction (NMJ) is the target of a variety of immune-mediated disorders, usually classified as presynaptic and postsynaptic, according to the site of the antigenic target and consequently of the neuromuscular transmission alteration. Although less common than the classical autoimmune postsynaptic myasthenia gravis, presynaptic disorders are important to recognize due to the frequent association with cancer. Lambert Eaton myasthenic syndrome is due to a presynaptic failure to release acetylcholine, caused by antibodies to the presynaptic voltage-gated calcium channels. Acquired neuromyotonia is a condition characterized by nerve hyperexcitability often due to the presence of antibodies against proteins associated with voltage-gated potassium channels. This review will focus on the recent developments in the autoimmune presynaptic disorders of the NMJ.

Effect of Duchenne muscular dystrophy on enzymes of energy metabolism in individual muscle fibers

Metabolism ◽  
1987 ◽  
Vol 36 (8) ◽  
pp. 761-767 ◽  
Author(s):  
Maggie M.-Y. Chi ◽  
Carol S. Hintz ◽  
Deidre McKee ◽  
Steven Felder ◽  
Natasha Grant ◽  
...  
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Energy Metabolism ◽  
Muscular Dystrophy ◽  
Muscle Fibers ◽  
Individual Muscle ◽  
Enzymes Of Energy Metabolism

Effect of microgravity on metabolic enzymes of individual muscle fibers

1990 ◽  
Vol 4 (1) ◽  
pp. 55-63 ◽  
Author(s):  
Jill K. Manchester ◽  
Maggie M.‐Y. Chi ◽  
Beverly Norris ◽  
Bernard Ferrier ◽  
Igor Krasnov ◽  
...  
Keyword(s):  
Muscle Fibers ◽  
Metabolic Enzymes ◽  
Individual Muscle

Effect of ischemia on neuromuscular transmission: a single fiber EMG study

1985 ◽  
Vol 61 (3) ◽  
pp. S126
Author(s):  
P. Girlanda ◽  
R. Dattola ◽  
C. Venuto ◽  
C. Messina
Keyword(s):  
Neuromuscular Transmission ◽  
Single Fiber

scholarly journals A three-dimensional culture model of innervated human skeletal muscle enables studies of the adult neuromuscular junction and disease modeling

2018 ◽  
Author(s):  
Mohsen Afshar Bakooshli ◽  
Ethan S Lippmann ◽  
Ben Mulcahy ◽  
Nisha R Iyer ◽  
Christine T Nguyen ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Neuromuscular Junction ◽  
Motor Neuron ◽  
Motor Neurons ◽  
Human Skeletal Muscle ◽  
Disease Modeling ◽  
De Novo ◽  
Muscle Fibers ◽  
Three Dimensional ◽  
Adult Human

SummaryTwo-dimensional (2D) human skeletal muscle fiber cultures are ill equipped to support the contractile properties of maturing muscle fibers. This limits their application to the study of adult human neuromuscular junction (NMJ) development, a process requiring maturation of muscle fibers in the presence of motor neuron endplates. Here we describe a three-dimensional (3D) co-culture method whereby human muscle progenitors mixed with human pluripotent stem cell-derived motor neurons self-organize to form functional NMJ connections within two weeks. Functional connectivity between motor neuron endplates and muscle fibers is confirmed with calcium transient imaging and electrophysiological recordings. Notably, we only observed epsilon acetylcholine receptor subunit protein upregulation and activity in 3D co-culture. This demonstrates that the 3D co-culture system supports a developmental shift from the embryonic to adult form of the receptor that does not occur in 2D co-culture. Further, 3D co-culture treatments with myasthenia gravis patient sera shows the ease of studying human disease with the system. This work delivers a simple, reproducible, and adaptable method to model and evaluate adult human NMJ de novo development and disease in culture.

Repetitive Nerve Stimulation Studies

2016 ◽  
pp. 328-346
Author(s):  
Kathleen D. Kennelly
Keyword(s):  
Neuromuscular Junction ◽  
Nerve Stimulation ◽  
Nerve Conduction ◽  
Neuromuscular Transmission ◽  
Repetitive Stimulation ◽  
Nerve Conduction Studies ◽  
Clinical Correlation ◽  
Repetitive Nerve Stimulation ◽  
Anatomy And Physiology

Repetitive stimulation is a technique that evaluates the function of the neuromuscular junction. It is important not only in the detection, clarification, and follow-up of neuromuscular junction diseases, but also in excluding these disorders in patients with symptoms of fatigue, vague weakness, diplopia, ptosis, and malaise, or with objective weakness of uncertain origin. The technique requires knowledge of the physiology and pathophysiology of neuromuscular transmission and the basic techniques of nerve conduction studies. This chapter includes a brief review of the anatomy and physiology of the neuromuscular junction as it applies to repetitive stimulation, a detailed discussion of the technique, the pitfalls that can occur if not carried out correctly, criteria used to classify the results as normal or abnormal, the patterns of abnormalities that can be seen, and the clinical correlation of those abnormalities with the various different disorders of neuromuscular transmission.

Long-term facilitation alters transmitter releasing properties at the crayfish neuromuscular junction

1986 ◽  
Vol 55 (3) ◽  
pp. 484-498 ◽  
Author(s):  
J. M. Wojtowicz ◽  
H. L. Atwood
Keyword(s):  
Neuromuscular Junction ◽  
Synaptic Transmission ◽  
Time Course ◽  
Muscle Fibers ◽  
Low Frequencies ◽  
Before And After ◽  
Binomial Parameter ◽  
Small Muscle ◽  
Long Term Facilitation

Synaptic transmission at the neuromuscular junction of the excitatory axon supplying the crayfish opener muscle was examined before and after induction of long-term facilitation (LTF) by a 10-min period of stimulation at 20 Hz. Induction of LTF led to a period of enhanced synaptic transmission, which often persisted for many hours. The enhancement was entirely presynaptic in origin, since quantal unit size and time course were not altered, and quantal content of transmission (m) was increased. LTF was not associated with any persistent changes in action potential or presynaptic membrane potential recorded in the terminal region of the excitatory axon. The small muscle fibers of the walking-leg opener muscle were almost isopotential, and all quantal events could be recorded with an intracellular microelectrode. In addition, at low frequencies of stimulation, m was small. Thus it was possible to apply a binomial model of transmitter release to events recorded from individual muscle fibers and to calculate values for n (number of responding units involved in transmission) and p (probability of transmission for the population of responding units) before and after LTF. In the majority of preparations analyzed (6/10), amplitude histograms of evoked synaptic potentials could be described by a binomial distribution with a small n and moderately high p. LTF produced a significant increase in n, while p was slightly reduced. The results can be explained by a model in which the binomial parameter n represents the number of active synapses and parameter p the mean probability of release at a synapse. Provided that a pool of initially inactive synapses exists, one can postulate that LTF involves recruitment of synapses to the active state.

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