E.V. Loseva - Dr.Sci. (Biol.), Chief Research Scientist, Laboratory of Functional Neurocytology, Institute of Higher Nervous Activity and Neurophysiology RAS (Moscow). E-mail: losvnd@mail.ru N.A. Loginova - Ph.D. (Biol.), Research Scientist, Laboratory of Functional Neurocytology, Institute of Higher Nervous Activity and Neurophysiology RAS (Moscow). E-mail: nadezhda.loginova1982@gmail.com V.V. Gavrilov - Ph.D. (Psychol.), Senior Research Scientist, Laboratory of Psychophysiology, Institute of Psychology RAS (Moscow). E-mail: nvvgav@mail.ru

Morphometric studies of cytoarchitectonic of distinct areas of neocortex under visual deprivation in comparison with normal access to optical parameters of environment could shed light on an organization of activity of cortical areas. The aim of this study was to analyze a thickness of cortical layers in different cortical areas in rats drown up in the complete darkness (D) and in natural lighting (L). We prepared 18...20 µm frontal plane serial slices of motor (a.3.20), posterior retrosplenial (p.4.52) and primary visual (p.7.30) areas of the cortex in 4-month-old rats (D group, n = 8; L group, n = 10). The slices were stained with Nissl-s method with the subsequent lighting procedure through alcohol of the increasing concentrations. Three slices from each level have been taken for analysis. Photos of selected slices made with Axioplan-2, (Germany) (50-fold amplification) were analyzed with computer ImageJ program. Statistical comparison of groups was carried out by nonparametric criterion of Mann-Whitney for independent groups, using the software package of STATISTICA-6. It was found a significant decreasing of thickness, as of visual and of retrosplenial areas of the neocortex (p < 0,05 и p < 0,01, respectively), but not of motor one. We also found the decreasing of thickness of some individual layers in all areas under study: the 2nd (p < 0,05), the 3rd (p < 0,01) and the 6th (p < 0,1, tendency) layers in visual cortex; the 1st (p < 0,05), the 2nd+3rd (p < 0,1), the 5th (p < 0,01) and the 6th (p < 0,1) ? in retrosplenial cortex; the 2nd+3rd (p < 0,05) and the 4th (p < 0,01) ? in motor cortex. Thus, a thickness of layers in visual, motor and, even in a great extent, in retrospleanial areas of neocortex is decreased in rats grown up in darkness. We suppose, that on the basis of comparison of these morphogenetic data with electrophysiological indicators of brain activity in behavior, it will be possible to find out the role of vision in organization of behavior and formation of individual experience in rats growing up in darkness and in condition of natural lighting, that is having different ontogenesis of visual system. Supported by RFBR grant Psychophysiological bases of the formation of individual experience under visual deprivation in ontogenesis № 15-06-06925 а.

 

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