Quantitative morphological characteristics of developing neurons of the sensory trigeminal nuclei in kittens

Abstract

Five types of neurons were distinguished in the sensory nuclei of the trigeminal nerve, stained by Golgi's method, in kittens aged 1–5 days and 30 days: reticular and short-dendritic cells (with few branches), and multipolar giant cells, arborescent, and bushy neurons (densely branching). Yet another special type of cell, with a few short dendrites and one long dendrite, was distinguished in preparations from the brain of newborn kittens. Analysis of the dimensions of the bodies, the number, length, and ramification of the dendrites, and the total ramification of the cell yielded quantitative morphological characteristics of these neurons at different times of development. These types of neurons differed in their qualitative and quantitative parameters and in the features of their maturation.Bushy neurons underwent regressive changes during development. Foci of maximal ramification of dendrites of densely branched neurons changed their location during the first months of life relative to the cell body, moving into the more distal regions of the dendrites. Differences in orientation of dendrites with foci of maximal ramification were found relative to neighboring brain formations, which depended on the types of cells and the animal's age. The high level of maturity of trigeminal neurons at birth was demonstrated.