[Cytoarchitectonics of the cerebral cortex in mice selected for high and low brain weight]

The cortex cytoarchitectonics was studied in mice, which had been genetically selected for high (H-line) and low (L-line) brain weight and manifested some differences in their behaviour. Microscopic brain sections were analysed to estimate the areas of the neocortex, archicortex and paleocortex and to investigate quantitatively the microstructure in different zones of the neocortex. In the H-line, absolute value of total cortical area is, on the average, by 18% higher than that in the L-line--mainly owing to the larger area of neocortex, while the mean values of neurone volume fraction and profile field reveal no significant difference between the H- and L-line. Hence, the total number of neurones in the neocortex of mice from H-line should be greater, as compared with the L-line. Besides, within the framework of the same cerebral organization in general, the obtained data are indicative of a somewhat higher spatial differentiation of the neocortex in mice from the H-line.