123 ISSN 0362-1197, Human Physiology, 2017, Vol. 43, No. 2, pp. 123–131. © Pleiades Publishing, Inc., 2017. Original Russian Text © T.A. Tsekhmistrenko, V.A. Vasilyeva, N.S. Shumeiko, 2017, published in Fiziologiya Cheloveka, 2017, Vol. 43, No. 2, pp. 5–14. Structural Rearrangements of the Cerebral Cortex in Children and Adolescents T. A. Tsekhmistrenko a, b, *, V. A. Vasilyeva a , and N. S. Shumeiko a a Institute of Developmental Physiology, Russian Academy of Education, Moscow, 119121 Russia b Peoples’ Friendship University of Russia, Moscow, 117198 Russia *e-mail: tsekhmistrenko2010@yandex.ru Received May 31, 2016 Abstract—The cortical formations of the brain involved in visual functions (the occipital and temporo-pari- eto-occipital areas, the oculomotor area of the prefrontal cortex), as well as the motor cortex in the represen- tation zone of the arm and the medial region of the frontal cortex adjacent to the limbic lobe, were studied in post-mortem material. The thickness of the cortex and cortical layer III, the sizes of pyramidal neurons, the specific volumes of neurons and intracortical vessels were studied in subjects of both sexes, from birth to the age of 20 years, at yearly intervals (103 observations) using histological techniques, computer morphometric and stereological analysis. The thickness of the cortex of the cerebral hemispheres was observed to intensively increase from birth to the age of 3 years in the occipital, temporo-parieto-occipital and prefrontal cortical areas involved in visual recognition processes. The increase in thickness of the cerebral cortex continues until the age of 6 in the occipital cortex and in the oculomotor area, until the age of 7 years in the temporo-parieto- occipital area and the medial prefrontal area, and until the age of 8–9 years in the motor cortex. The sizes of pyramidal neurons increase until the age of 6 years in the motor cortex, until the age of 8 years on the medial surface of the frontal lobe, and until the age of 9–10 years in the temporo-parieto-occipital area and in the dorsolateral area of the prefrontal cortex. The specific volume of neurons and blood vessels in the cortex of the cerebral hemispheres decreases and the volume of intracortical fibers increases throughout the ascending ontogeny, which is manifested most intensively in the prefrontal cortex. Keywords: human cerebral cortex, prefrontal cortex, motor cortex, temporo-parieto-occipital cortical area, cortical thickness, layer III thickness, volume of pyramidal neurons, specific volumes of neurons and intra- cortical vessels, morphometry, stereometry, postnatal ontogeny, visual perception DOI: 10.1134/S0362119717020153 Researchers are more and more interested in pecu- liarities of the development of functionally different areas of cerebral cortex, primarily the projection-asso- ciative and associative cortical formations exhibiting relatively late maturation [1, 2]. The transformations of cyto- and fibroarchitectonics of the cortex in ontog- eny, the formation of interneuronal connections, and the search of the factors stabilizing the growth and development of cortical microstructure are still in the spotlight [3]. The development of techniques for intra- vital imaging of brain structures allows the detailed study of the volumetric ratios of gray and white sub- stance in different parts of the human brain [4]. There is a growing interest in the study of cortical thickness, since the changes in this characteristic closely cor- relate with a number of histophysiological and func- tional parameters being human health indicators [5, 6]. Special attention is focused on the parameters characterizing the functional potential of the cerebral cortex, in particular, its vascularization, which deter- mines the intensity of metabolic processes occurring in the cortex [7]. The attempts are made to virtually reconstruct the intracortical microvascular bed and its modifications depending on the effects of various fac- tors [8]. Undoubtedly, the available intravital analysis opens new ways to the study of individual and age- related characteristics of structural organization of the brain [9]. In spite of undoubted progress in methodological support for neuromorphological studies, there are still problems that are most effectively solved by using clas- sical histological techniques in combination with quantitative statistical analysis. The methods based on the phenomenon of nuclear magnetic resonance restrict the assessment of cortex stratification so that brain tissue cannot be studied at the cellular level. The studies of age-related changes in and regional specific- ity of the vascular component of human cerebral cor- tex are also restricted [10]. The analysis of such details makes it possible to trace more clearly not only age- related but also regionally specific peculiarities of the development of functionally and phylogenetically dif-