Brains from 74 children aged from birth to 12 years were used to study fibroarchitectonic characteristics in topographically and functional diverse cortical zones (the temporal-parietal-occipital subregion, occipital, precentral, postcentral, and frontal areas) of the cerebral cortex; children aged up to 12 months were studied on the basis of one-month age intervals. Studies were performed by computer analysis of optical images on frontal sections stained with Nissl cresyl violet and silver nitrate impregnation by the modified Peters method. Data on the rate of increase in the thickness of radial bundles of fibers, the distances between bundles, and the age dynamics of the ratios of the specific volumes of neurons and fibers in fields 3, 4p, 6op, 17, 19, 37ac, 44, and 32/10 were obtained. These measurements showed that age-related transformation of fibroarchitectonics in fields of the sensorimotor, somatosensory, occipital, temporal-parietal-occipital, and frontal areas occurred at different times and with different intensities; the most significant changes were seen in the first 2-3 years of life, with changes continuing at a less intense level to age 9-12 years.

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Interest in studies of structural changes in the human cerebellum during post-natal ontogenesis continues to increase. The cerebellar cortex, an integral component of the brain's motor and sensory systems [2], is directly involved in higher integrative processes involved in organizing perception, attention, long-term memory, speech activity, and the effectiveness of cognitive activity as a whole [1,4]. Studies of age-related changes in the structure of cerebellar cortical neurons could provide a basis for identifying a number of common characteristics of the formation of systems of complex organization, such as the cortical formations of the human brain, especially the associative cortical structures [10].The aim of the present work was to study agerelated and individual quantitative changes in pyriform neurons (PN) (Purkinje cells) and cortical areas in the human cerebellum; these provide efferent influences to spinal, brainstem, and subcortical structures of the central nervous system during the performance of motor coordination involving vision. Additionally, studies were directed to characterizing age-related changes in the development of PN in the visual zone of the cerebellar cortex. MATERIALS AND METHODSThe cerebellum was collected from each of 85 human cadavers of both sexes and aged from birth to 20 years. The main group consisted of virtually healthy people who suffered violent deaths without trauma to 405 the brain or cerebellum. Fragments were collected from strictly defined points in the area of the pyramid (pyramis vermis; paleocerebellum) and the right and left digastric lobes (neocerebellum) of the cerebellar cortex. Material was processed by standard histological methods; paraffin sections (thickness 10 /am) were strained with cresyl violet as described by Nissl, and celluloidin sections (120 gin) were impregnated with silver nitrate by the Golgi method. Preparations were studied on a computer optical image analysis system using the BIOSCAN-An program with unified image depth, brightness, and contrast, as well as by quantitative neuron image processing methods. During studies with optical files, program features were used allowing oblique sections of neurons to be excluded from analysis. Histological material from children in the first year of life was grouped by month, while material from older subjects was grouped by year. Morphometric analysis included measurements of the areas of PN profile fields. For each individual section, the mean and the error of the mean were determined and histograms were plotted to show the ratio of neurons of different size classes. The number of neurons examined per slice was at least 25, and the number per preparation was at least 100. The limits of the size classes were defined from 0.1 gm 2 with steps of 33.2 ~tm z (i.e., class 1 included PN with areas from 0.1 to 33.3 ~tm 2, class 2 included those with areas from 33.4 to 66.6 gm 2, etc.). Evaluation and comparison of mean values with their calculated standard errors and standard deviations, and the standard err...

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