scholarly journals STEREOLOGY OF NEURONAL CONNECTIONS (MYELINATED FIBERS OF WHITE MATTER AND SYNAPSES OF NEOCORTEX) IN HUMAN BRAIN

2011 ◽  
Vol 22 (1) ◽  
pp. 171 ◽  
Author(s):  
Yong Tang ◽  
Jens R Nyengaard ◽  
Bente Pakkenberg ◽  
Hans Jørgen G Gundersen
Keyword(s):  
White Matter ◽  
Volume Density ◽  
Nerve Fibers ◽  
Diameter Distribution ◽  
Numerical Density ◽  
Myelinated Nerve ◽  
Myelinated Nerve Fibers ◽  
Myelinated Fibers ◽  
Total Length ◽  
Human Autopsy

Unbiased stereological sampling and counting techniques for estimating the total length, total volume and diameter distribution of myelinated nerve fibers in white matter and the total number of synapses in neocortex of human autopsy brains were described. Uniform random sampling of tissues from entire hemisphere was performed. The total volume and total length of myelinated fibers in white matter were estimated from the product of the volume of white matter obtained with the Cavalieri principle and the volume density and length density of myelinated fibers in white matter, respectively. The volume density of myelinated nerve fibers in white a matter was estimated with a point counting method. The length density of myelinated fibers in white matter was estimated from the isotropic, uniform random sections that were ensured by the sector. The diameter of myelinated fibers was derived by measuring the profile diameterperpendicular to its longest axis. The ethanolic phosphotungstic acid staining technique was modified for staining synapses in human autopsy brains. The total number of synapses in each neocortical region was estimated as the product of the volume of each neocortical region and the numerical density of synapses in each region. The numerical density of synapses in each neocortical region was obtained with the disector at the electron microscopical level. The presented methods will be useful for quantitative studies of the changes of myelinated nerve fibers and synapses in various distinct regions of the central nervous system due to development, aging and diseases.

scholarly journals APPLICATION OF STEREOLOGICAL METHODS TO STUDY THE WHITE MATTER AND MYELINATED FIBERS THEREIN OF RAT BRAIN

2011 ◽  
Vol 27 (2) ◽  
pp. 125 ◽  
Author(s):  
Shu Yang ◽  
Chen Li ◽  
Wei Zhang ◽  
Weiwei Wang ◽  
Jens R Nyengaard ◽  
...  
Keyword(s):  
White Matter ◽  
Rat Brain ◽  
Estimation Procedure ◽  
Volume Density ◽  
Nerve Fibers ◽  
Sampling Variance ◽  
White Matter Volume ◽  
Matter Volume ◽  
Myelinated Fibers ◽  
Total Length

An efficient and unbiased stereological method was applied to estimate the white matter volume, the total volume, total length and mean diameter of the myelinated fibers in the white matter and the total volume of the myelin sheaths in the white matter of rat brain. The white matter volume was obtained with the Cavalieri principle. Four tissue blocks were sampled from the entire white matter in a uniform random fashion. The length density of the myelinated fibers in the white matter was obtained from the isotropic, uniform, random sections ensured by the isector. The volume density of the myelinated fibers in the white matter was estimated by point counting. The total length and the total volume of the myelinated fibers in the white matter were estimated by multiplying the white matter volume and the length density and the volume density of the myelinated fibers in the white matter, respectively. The size of nerve fibers was derived by measuring the profile diameter perpendicular to its longest axis. The results were satisfactory in the sense that the sampling variance introduced by the stereological estimation procedure was a minor fraction of the observed variance. The comparison of the white matter and the myelinated fibers in the white matter between rat brain and human brain was also made in the present study.

scholarly journals Age-Dependent Histomorphometrical Values of the Sciatic Nerve Regeneration in Rats after Cutting and Microsurgical Suturing

2021 ◽  
Vol 10 (3) ◽  
pp. 83-90
Author(s):  
N. A. Shchudlo ◽  
T. N. Varsegova ◽  
M. M. Shchudlo
Keyword(s):  
Sciatic Nerve ◽  
Nerve Regeneration ◽  
Nerve Fibers ◽  
Diameter Distribution ◽  
Numerical Density ◽  
Myelinated Nerve ◽  
Experimental Animals ◽  
Intact Group ◽  
Myelinated Fibers ◽  
Sciatic Nerve Regeneration

The effect of ageing on the morphofunctional features of nerves and the process of their posttraumatic regeneration has been studied in details. However, it is not known, whether there are differences of the neuroregeneration potential in the young, adult and mature experimental animals.The aim of the study was to evaluate histomorphometrical parameters of the rat sciatic nerve regeneration after cutting and microsurgical suturing depending on their age.Materials and Methods. The study included 15 white laboratory Wistar rats aged 5–6 (young), 8–10 (adult) and 12 months (mature). The sciatic nerve was transected at the level of the middle third of the thigh with microsurgical scissors and sutured with six epi-perineural stitches in the animals. In 4 months the animals were euthanized. Sections of sciatic nerves distal to the levels of sutures were put into araldite, semi-thin slices (0.5–1.0 mkm) were obtained for histomorphometric analysis. Thirteen intact animals were selected as control. Statistical processing was performed using nonparametric methods.Results. The numerical density of endoneural vessels in nerves of operated rats was higher than that in the intact ones, but in mature animals it was significantly lower than in young and adult ones (p<0.001). The numerical density of endoneural cells nuclei in young experimental animals did not differ from that of the intact ones, but in animals from the adult and mature groups it was more than four times higher than in animals from the young group (p<0.001). The numerical density of regenerating myelinated nerve fibers in animals of the young and adult groups did not differ from that of the intact nerve, in animals of the mature group it increased in 2.5 times (p<0.001). The numerical density of degenerating myelinated fibers in the operated animals of experimental groups was higher than in the intact group (two times, six times and 11 times higher, respectively). The diameter distribution of the regenerating myelinated fibers in animals of all groups differed from that of the intact control animals.Conclusions. The data obtained demonstrate a significant decrease in the regenerative potential of Schwann cells and neurons in adult and mature animals compared with the young ones.

Side differences of the age-related changes in the white matter and the myelinated nerve fibers in the white matter of female rats

2011 ◽  
Vol 492 (2) ◽  
pp. 119-123 ◽  
Author(s):  
Xiao-yan Shi ◽  
Yuan-yu Zhao ◽  
Shu Yang ◽  
Chen Li ◽  
Lin Chen ◽  
...  
Keyword(s):  
White Matter ◽  
Nerve Fibers ◽  
Female Rats ◽  
Myelinated Nerve ◽  
Myelinated Nerve Fibers ◽  
Age Related ◽  
Age Related Changes

Transitory traumatic paraplegia: electron microscopy of early alterations in myelinated nerve fibers

1972 ◽  
Vol 36 (4) ◽  
pp. 407-415 ◽  
Author(s):  
George J. Dohrmann ◽  
Franklin C. Wagner ◽  
Paul C. Bucy
Keyword(s):  
Electron Microscopy ◽  
Spinal Cord ◽  
White Matter ◽  
Nerve Fibers ◽  
Myelinated Nerve ◽  
Content Type ◽  
Myelinated Nerve Fibers ◽  
Myelin Sheaths ◽  
Fine Print

✓ The white matter of the monkey spinal cord was examined by electron microscopy during the first 4 hours following a contusion sufficient to produce a transitory paraplegia. At 5 min after injury the myelinated nerve fibers resembled those of the control animals. By 15 and 30 min after contusion, selected fibers were noted to have moderately enlarged periaxonal spaces. Attenuated myelin sheaths, splaying of the myelin lamellae, and a marked increase in the periaxonal spaces were present in affected nerve fibers at 1 hr following trauma. By 4 hrs after contusion approximately one-fourth of the fibers showed breakage of the myelin sheaths and consequent denuding of axons or marked attenuation of the myelin sheaths, greatly enlarged periaxonal spaces, and degeneration of the associated axons.

Sex differences in the white matter and myelinated nerve fibers of Long-Evans rats

2008 ◽  
Vol 1216 ◽  
pp. 16-23 ◽  
Author(s):  
Shu Yang ◽  
Chen Li ◽  
Wei Zhang ◽  
Weiwei Wang ◽  
Yong Tang
Keyword(s):  
Sex Differences ◽  
White Matter ◽  
Nerve Fibers ◽  
Myelinated Nerve ◽  
Myelinated Nerve Fibers ◽  
Long Evans

Multi-Step Clustering Approach of Myelinated Nerve Fibers in Experimental Neuromorphology

2021 ◽  
Vol 12 (2) ◽  
pp. 73-91
Author(s):  
Taras Kotyk ◽  
Nadiya Tokaruk ◽  
Viktoria Bedej ◽  
Mariia Hryshchuk ◽  
Oksana Popadynets ◽  
...  
Keyword(s):  
Nerve Fibers ◽  
Morphometric Parameters ◽  
Software Environment ◽  
Myelinated Nerve ◽  
Myelinated Nerve Fibers ◽  
Model Based Clustering ◽  
Myelinated Fibers ◽  
Clustering Approach ◽  
Functional Features ◽  
High Level

One of the unresolved issues in experimental neuromorphology is searching for a solution for myelinated nerve fibers clustering on set of morphometric parameters. Therefore, in this article, a new approach for cluster analysis of myelinated fibers is proposed based on their morpho-functional features. The proposed clustering approach was developed in R software environment and uses model-based clustering, which is performed in few steps with increasing number of morphometric parameters on each next step. Applying the proposed clustering solution shown high similarity of identified groups' morphometric parameters with respective physiological types of myelinated A-fibers. This fact, in addition to the algorithm implementation simplicity, facilitates its use on identifying clusters of myelinated fibers that represent different myelinated fibers subpopulation in experimental neuromorphological research with high level of reliability.

Sign in / Sign up

Export Citation Format

Share Document