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Neurons and glial cells were studied by computerized morphometry in segments of the ventral and dorsal areas of the compact zone of the substantia nigra (CZSN) of the brain in autopsy material obtained from six men and three women aged 52–87 years. Neuron body and nuclear sizes were found to be greater in segments of the ventral area of the CZSN than in segments of the dorsal area. Neuron and glial cell densities in the ventrolateral segment were higher than in segments of the dorsal area. The glial index in the ventromedial segment was lower than in segments of the dorsal area. These morphometric differences between CZSN segments need to be considered for assessment of morphological changes in the substantia nigra associated with both age-related involution and pathological processes.

The aim of the present work was to undertake a comparative study of the effects of prenatal alcoholization of the histological characteristics of neurons in the frontal cortex of the brains of rats of different ages. Experiments were performed on 175 mongrel white rats – the offspring of 25 females given 15% ethanol as drinking solution throughout pregnancy. The cerebral cortex was studied on postnatal days 2–90 using histological, histochemical, and morphometric methods. An increase (on days 2 and 5) followed by a decrease (on days 10 and 90) was seen in cortical thickness, with a decrease in neuron body size (on days 20–90), a decrease in the number of neurons in cortical layer V, a decrease in the number of normochromic cells, and increases in the numbers of hyperchromic shrunken neurons and ghost cells throughout the study period. Antenatal alcoholization in rats induced various histological changes in the frontal cortex, which were long-lasting and progressive during postnatal ontogeny.

The effects of rhythmic light stimulation on the postnatal development of the visual system were studied in relation to the formation of Meynert neurons in field 17 and the posteromedial area of the lateral suprasylvian sulcus (PMLS) in kittens reared with exposure to flashing light (frequency 15 Hz). Neuron body cross-sectional area and cytochrome oxidase (CO) activity levels were measured in the visual cortex of control (n = 6) and stimulated (n = 6) animals. Increases in the level of CO activity were seen in Meynert cells in field 17 and the PMLS area, by about 37%. There was also a decrease in the cross-sectional area of the bodies of Meynert neurons located in the PMLS, by 20% compared with normal. The existence of functional impairments of the Y conducting channel in stimulated animals and the possibility that binocular vision is suppressed are discussed.