The determination of the instantaneous velocity of axonally transported organelles from filmed records of their motion

1982 ◽  
Vol 60 (5) ◽  
pp. 670-679 ◽  
Author(s):  
K. J. Koles ◽  
K. D. McLeod ◽  
R. S. Smith
Keyword(s):  
Power Spectra ◽  
Computational Procedure ◽  
Dark Field ◽  
Nerve Fibers ◽  
Low Noise ◽  
Instantaneous Velocity ◽  
Mean Velocity ◽  
Myelinated Nerve ◽  
Motion Picture Film ◽  
Band Limited

A computational procedure is described for obtaining reproducible, low noise estimates of the instantaneous velocity of axonally transported organelles. Axonally transported organelles were detected in myelinated nerve fibers from Xenopus laevis by dark-field microscopy. The motion of the organelles was recorded on motion picture film at 3 frames/s, and the position of organelles travelling in the retrograde direction was obtained as a pair of x (axial) and y (transverse) coordinates at each 0.33-s interval. The trend in organelle movement with time was calculated for each of the series of x and y coordinates by linear regression. This trend was removed from the measurements of x and y to yield sets of trend-free displacements. The trend yielded a measure of the mean velocity of the organelle in each of the two orthogonal directions. Power spectra of the deviations in x and y about the trend were calculated. For 133 particles studied, 99% of the power in the trend-free deviations occurred at frequencies below 0.3 Hz. The peak power in the x and y deviations occurred at a frequency of 0.1 Hz or less. Positional deviations about the trend were treated with a discrete 21-term differentiating filter that attenuated frequencies above 0.3 Hz. Instantaneous velocities for the organelles were obtained by adding the result of the band-limited differentiation to the appropriate estimates of mean velocity. The 21-term method was compared with a commonly used 2-term approximation to a differentiator and was shown to produce velocity estimates with about one order of magnitude less error. Estimates of organelle velocity obtained with the 21-term method indicate that saltatory particle motion may be viewed either as a smooth variation of particle velocity with respect to time or as an irregular, or discontinuous, variation of velocity with respect to particle position.

Microtubule and Neurofilament Densities in Amphibian Spinal Root Nerve Fibers: Relationship to Axoplasmic Transport

1973 ◽  
Vol 51 (11) ◽  
pp. 798-806 ◽  
Author(s):  
Richard S. Smith
Keyword(s):  
Dorsal Root ◽  
Dark Field ◽  
Nerve Fibers ◽  
Axoplasmic Transport ◽  
Spinal Root ◽  
Myelinated Nerve ◽  
Dorsal Roots ◽  
Dark Field Microscopy ◽  
Spinal Roots ◽  
Ventral Roots

Dark-field microscopy of living myelinated nerve fibers from the spinal roots of Xenopus laevis revealed many spherical organelles moving in the axoplasm of fibers from the ventral roots and in fibers just distal to the dorsal root ganglion. Similar organelles were present but few were seen to move along fibers from the dorsal roots central to the ganglion. This observation prompted an ultrastructural study of microtubule and neurofilament densities in the myelinated fibers of the spinal roots. The density of microtubules was significantly less in fibers from the central part of the dorsal roots than in the rest of the spinal root system. Neurofilament densities were equivalent in all parts of the roots. Microtubules showed a significant association with mitochondria in the ventral roots and in the dorsal roots distal to the ganglion, but no significant association was obtained for the dorsal roots central to the ganglion. The meaning of these results in the axoplasmic transport of large organelles is discussed.

Mean velocity of optically detected intraaxonal particles measured by a cross-correlation method

1976 ◽  
Vol 54 (6) ◽  
pp. 859-869 ◽  
Author(s):  
R. S. Smith ◽  
Z. J. Koles
Keyword(s):  
Cross Correlation ◽  
Correlation Method ◽  
Nerve Fibers ◽  
Mean Velocity ◽  
Myelinated Nerve ◽  
Optical Signals ◽  
Accuracy And Precision ◽  
Small Collection ◽  
The Mean ◽  
Optically Detected

A method which uses the cross correlation of optical signals is described for the determination of the mean velocity of somatopetally moving particles within nerve fibers. The method was validated by simulation experiments and by comparing the results with those obtained by averaging collections of velocities of individual particles. The significant contribution of the method is that it allows objective and rapid serial evaluations of mean particle velocity within individual nerve fibers with good accuracy and precision. A series of results from normal myelinated nerve fibers from Xenopus laevis is presented. Considerable variation (up to 50%) in mean velocity was found between individual nerve fibers. The mean of all determinations indicates that the mean velocity of somatopetally moving particles in axons with diameters > 10 μm is in the region of 1.14 μm/s at a temperature of 22–24 °C. The findings are compared with the small collection of such determinations which have been reported in the literature.

Detection of Organelles in Myelinated Nerve Fibers by Dark-Field Microscopy

1972 ◽  
Vol 50 (5) ◽  
pp. 467-469 ◽  
Author(s):  
R. S. Smith
Keyword(s):  
Optical Detection ◽  
Dark Field ◽  
Nerve Fibers ◽  
Spherical Particles ◽  
Axial Motion ◽  
Myelinated Nerve ◽  
Myelinated Nerve Fibers ◽  
Adult Rat ◽  
Dark Field Microscopy

Dark-field microscopy improves the optical detection of intraaxonal organelles. In living myelinated nerve fibers of the adult rat and the adult toad, fast (approximately 1 μm/s) somatopetal and somatofugal movement of near-spherical particles was seen. Rod-shaped organelles were also detected in nerve fibers from both the rat and the toad, but these organelles showed no axial motion.

HISTOMETRIC AND ULTRASTRUCTURAL ORGANIZATION OF THE NERVIMUSCULAR TERMINALS OF SKELETAL MUSCLES AT A HYPOKINESIA

2019 ◽  
pp. 55-63
Author(s):  
Z. M. Yaschyshyn ◽  
S. L. Popel
Keyword(s):  
Skeletal Muscles ◽  
Structural Adjustment ◽  
Muscle Fibers ◽  
Electron Microscopic Examination ◽  
Nerve Fibers ◽  
Ultrastructural Changes ◽  
Ultrastructural Organization ◽  
Electron Microscopic ◽  
Myelinated Nerve ◽  
Male Wistar Rats

The aim: to study the dynamics of histological and ultrastructural changes in muscle fibers and their neuromuscular endings under conditions of prolonged hypokinesia at different stages of ontogenesis. Methods. Studied skeletal muscles and their peripheral nervous apparatus of laboratory male Wistar rats aged 30 to 270 days. The restriction of motor activity was carried out in special canister cells for 30, 60, 90, and 240 days (5 animals for each term). To determine the type of muscle fiber, the Nahlas histochemical method was used, the Kulchitsky method was used to detect myelinated nerve fibers, the Bilshovsky-Gros method and the electron microscopic method to identify neuromuscular endings. Results. The data of histological and electron microscopic examination of skeletal muscle fibers and their neuromuscular endings under conditions of prolonged hypokinesia indicate their regular restructuring during the development of muscles, the formation of their synapses and structures that are associated with them at different stages of ontogenesis. Conclusion. The study provides an in-depth understanding of the relative frequency and nature of the disturbance of the neuromuscular endings during prolonged hypokinesia and its effect on the dynamics of structural adjustment of individual types of muscle fibers in ontogenesis.

HISTOMETRIC AND ULTRASTRUCTURAL ORGANIZATION OF THE NERVIMUSCULAR TERMINALS OF SKELETAL MUSCLES AT A HYPOKINESIA

2019 ◽  
pp. 55-63
Author(s):  
Z. M. Yaschyshyn ◽  
S. L. Popel
Keyword(s):  
Skeletal Muscles ◽  
Structural Adjustment ◽  
Muscle Fibers ◽  
Electron Microscopic Examination ◽  
Nerve Fibers ◽  
Ultrastructural Changes ◽  
Ultrastructural Organization ◽  
Electron Microscopic ◽  
Myelinated Nerve ◽  
Male Wistar Rats

The aim: to study the dynamics of histological and ultrastructural changes in muscle fibers and their neuromuscular endings under conditions of prolonged hypokinesia at different stages of ontogenesis. Methods. Studied skeletal muscles and their peripheral nervous apparatus of laboratory male Wistar rats aged 30 to 270 days. The restriction of motor activity was carried out in special canister cells for 30, 60, 90, and 240 days (5 animals for each term). To determine the type of muscle fiber, the Nahlas histochemical method was used, the Kulchitsky method was used to detect myelinated nerve fibers, the Bilshovsky-Gros method and the electron microscopic method to identify neuromuscular endings. Results. The data of histological and electron microscopic examination of skeletal muscle fibers and their neuromuscular endings under conditions of prolonged hypokinesia indicate their regular restructuring during the development of muscles, the formation of their synapses and structures that are associated with them at different stages of ontogenesis. Conclusion. The study provides an in-depth understanding of the relative frequency and nature of the disturbance of the neuromuscular endings during prolonged hypokinesia and its effect on the dynamics of structural adjustment of individual types of muscle fibers in ontogenesis.

scholarly journals THE SUBMICROSCOPIC ORGANIZATION OF AXON MATERIAL ISOLATED FROM MYELIN NERVE FIBERS

1953 ◽  
Vol 98 (3) ◽  
pp. 269-276 ◽  
Author(s):  
E. De Robertis ◽  
C. M. Franchi
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Phase Contrast ◽  
Nerve Fibers ◽  
Myelinated Nerve ◽  
Myelinated Nerve Fibers ◽  
Dense Granules ◽  
Small Clusters ◽  
Membranous Material ◽  
The Way

A technique has been developed for the extrusion of axon material from myelinated nerve fibers. This material is then compressed and prepared for observation with the electron microscope. All the stages of preparation and purification of the axon material can be checked microscopically and in the present paper they are illustrated with phase contrast photomicrographs. Observation with the electron microscope of the compressed axons showed the presence of the following components: granules, fibrils, and a membranous material. Only the larger granules could be seen with the ordinary microscope. A considerable number of dense granules were observed. Of these the largest resemble typical mitochondria of 250 mµ by 900 mµ. In addition rows or small clusters of dense granules ranging in diameter from 250 to 90 mµ were present. In several specimens fragments of a membrane 120 to 140 A thick and intimately connected with the axon were found. The entire axon appeared to be constituted of a large bundle of parallel tightly packed fibrils among which the granules are interspersed. The fibrils are of indefinite length and generally smooth. They are rather labile structures, less resistant in the rat than in the toad nerve. They varied between 100 and 400 A in diameter and in some cases disintegrated into very fine filaments (less than 100 A thick). The significance is discussed of the submicroscopic structures revealed by electron microscopy of the material prepared in the way described.

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