Aim: This article is devoted to the study of age-related changes in the body volume of pyramidal neurons (VP) of the human prefrontal (PFC) and posterior associative cortex (PAC) in children from birth to 7 years of age. Methods: The material consisted of left cerebral hemispheres obtained from 60 male individuals. We studied the areas 8, 45 and 10 in the PFC and area 37 in subareas 37ac, 37a, 37d in the PAC. For morphometry of pyramidal neurons in cortical sublayer III3, we used virtual images of serial frontal paraffin sections of cortex 10 thick stained by Nissl. We determined the mean value of VP (mean VP), the standard error of the mean, and the confidence interval for each age group. Results: The most significant changes in the mean VP in all studied cortical areas occurred during the first 6 months of life. The greatest increase in the VP was detected in the PFC from 3.5 to 7 years, and in the PAC from 1.5 to 3 years of age. There are close positive correlations between agerelated changes in the size of neurons in the PFC and in the PAC. Conclusion: In children, the development of pyramidal neurons of the external pyramidal plate in the PAC occurs earlier and at a more intensive pace compared to the PFC. We suggest that VP is an important quantitative indicator that allows us to assess the timing and rate of age-related structural changes in the cerebral cortex.

Perception and recognition of faces is supported by a network of nerve centers in the human brain that have different maturation periods in postnatal ontogenesis. In this article, we analyze the relationship between changes in the thickness of the cortex in facial recognition centers in children from birth to 12 years old. Methods. Histological material was obtained from the left cerebral hemispheres and bilaterally from the cerebellum of 62 boys who died from injuries without brain damage. The material was grouped at annual intervals. Measurements of the cortical thickness were carried out in field 37a in the fusiform face area on the medial surface of the occipital lobe, in field 10 on the lateral surface of the frontal pole, as well as in the lateral right and left parts of the posterior quadrangular lobule (H VI) of cerebellum. Morphometry was performed on virtual images of sagittal paraffin sections, stained with Nissl cresyl violet. The mean, standard error and confidence interval were calculated for the indicators of different age groups. Results. The most significant increase in cortical thickness in fields 37a and 10 occurs during the first year of life, at 2-3 and 6 years. Increases in cortical thickness in the lobule H VI of the on the right cerebellum are observed at 1, 2, and 7 years, on the left during the first two years of life. Evaluation of the relationship between age-related changes in cortical thickness using Spearman's rank correlation analysis showed that the strongest, direct and significant two-way relationship is between the indicators in the pairs field 37a & field 10 and field 10 & H VI on the right, a moderate significant relationship in the pair field 37a & H VI on the left. Conclusions. It is assumed that age-related changes in the cortical thickness in the centers of face recognition and their relationship reflect the stages of the formation of the facial processing in children. K E y w o r d s -cerebral cortex, cerebellar cortex, cortical thickness, facial recognition centers, children, postnatal ontogenesis.

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С применением гистологических и количественных методик изучали структурные преобразования пирамидных нейронов и фиброархитектоники префронтальной и задней ассоциативной коры большого мозга у детей от рождения до 6 лет. Показано, что значимые микроструктурные преобразования отмечаются на первом году жизни, а также к 3 и 5 годам. Выявленные структурные изменения по темпам и срокам соответствуют основным возрастным этапам становления высших регуляторных механизмов мозговой деятельности с участием исследованных корковых формаций мозга детей. Using histological and quantitative techniques, we studied structural transformations of pyramidal neurons and fibroarchitectonics of the prefrontal and posterior associative cortex in children from birth to 6 years of age. It was shown that significant microstructural transformations were observed in the first year of life, as well as by the age of 3 and 5 years. The revealed structural changes according to the rates and timing correspond to the main age stages of formation of the higher regulatory mechanisms of brain activity with the participation of the investigated cortical formations of children’s brains.