[Development of the brain stem reticular formation during ontogenesis of lower simians as compared with man]

The work has shown a number of common features in the structural organization of the brain stem reticular formation in the adult rhesus monkey and man. According to the peculiar features and developmental features the reticular nuclei may be divided into 3 sections (median, medial and lateral) having different genesis. In ontogenesis all the nuclei of the reticular formation undergo differentiation and specialization due to the complication of the brain as a whole. This process, however, goes differently in ontogenesis of the macaque and man which can be seen in the heterochronous rate of their development, namely, in the macaque the terms of maturation of the reticular nuclei are somewhat more accelerated. The work shows changes in the density of cells, the volume of neurones and all the reticular formation in relation to the volume of the brain stem as a whole. However, the differences found in ontogenesis of the macaque and man are mainly of quantitative and idioadaptive character.