Quantitative analysis of the change in neuronal numerical density of the human nucleus dentatus within development

Abstract

The role of the dentate nucleus is to coordinate input information coming from the lower olivary complex and various parts of the brainstem of the spinal marrow with the output information from the cerebellar cortex. To better understand functions and relations of the dentate nucleus it is highly important to study its development process. The aim of this study was to determine a possible mathematical model of decrease in neuronal numerical density of the human nucleus dentatus at different stages of development. This study included 25 fetal brains of different age (12.5-31 weeks of gestational age and one brain of a 6-day-old newborn). The brains were fixed in 10% formalin-alcohol solution and embedded in paraffin. Sections were cut at a thickness of 6, 15, and 30 microm and stained with cresyl violet. Each fifth section was analyzed using a light microscope, and numerical density of dentate nucleus neurons was established using the M42 Weibel's grid system. The obtained results revealed a constant decrease in numerical density value. The changes of numerical densities at different stages of development correspond with Boltzmann function principles. The first, almost perpendicular part of Boltzmann function corresponds with the development of the dorsomedial lamina and the appearance of ventrolateral lamina primordium. The second, more or less horizontal part of Boltzmann function corresponds with the development of both laminae. CONCLUSION. The obtained results indicate that Boltzmann function can be considered a mathematical model of change in neuronal numerical density of dentate nucleus at different stage of development.