Gydikov A

Influence of the muscle fibre end geometry on the extracellular potentials

Intra- and extracellular action potentials of isolated frog muscle fibres were recorded at different distances to the end of the fibre. The first and second time derivatives of the intracellular action potentials were also recorded. The intracellular action potentials and their first and second time derivatives were almost the same regardless of the place of recording. With the decrease in the axial distance to the end the extracellular action potentials changed gradually in a complicated manner from a shape similar to the second time derivative into a shape similar to the first time derivative. Extracellular potentials, having two negative maxima, were recorded over the terminal taper part of the fibres.These alterations were simulated by a mathematical model. It was shown that the changes in the shape of the extracellular action potentials around the end of the fibres were mainly due to the existence of the fibre end though a better correspondence of the experimentally recorded and the calculated extracellular action potentials was obtained when the morphology of the fibre end was taken into consideration.

Changes in the muscle fibre extracellular action potentials in long-lasting (fatiguing) activity

SummaryThe dependence of extracellular action potentials (ECAPs) of single frog muscle fibres on intracellular action potentials (ICAPs) was studied during long-lasting (fatiguing) activity.The conduction velocity, peak-to-peak amplitude and amplitudes of the separate phases of the first and second ICAP time derivatives decreased during long-lasting activity. The phases of the first and second ICAP space derivatives also decreased in amplitude and lengthened.ECAPs near the membrane were similar in shape and proportional in amplitude to

Extracellular potentials of a single myelinated nerve fiber in an unbounded volume conductor

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Changes in the shape of the extraterritorial potentials of tonic motor units, M- and H-responses of triceps surae muscles at different muscle lengths and under conditions of voluntary activation.

when recording at a distance from both the end of the fibre and the point of stimulation.At long radial distances, the amplitudes of the separate ECAP phases depended on the amplitude and length of the corresponding phases of

Electromyographic and vectorelectromyographic studies of potentials recorded from human single muscle fibers.

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Location of the motor unit electrical axis and determination of the muscle anisotropy ratio

.Thus the decrease in ECAP amplitude during long-lasting activity at long radial distances was less than at points close to the muscle fibre membrane.The consequences of these findings for the changes in electromyograms recorded by needle or superficial electrodes during long-lasting (fatiguing) activity are discussed.