LABORATORY OF NEUROMORPHOLOGY

(Head N.S.Merculieva)

In 1961, Prof. A. S. Iontov founded a new Laboratory to study morphological organization of the brain and principles of construction of nerve connections in mammals, including man. The main problem studied was organization of associative, commissural, and projectional connections in various areas of cerebral cortex parts of analyzers (visual, auditory, vestibular) by methods of light and electron microscopy, axonal marker transport, historadiography. There was revealed a two-side character of the visual and auditory cortex associative connections formed by intracortical fibers and the fibers passing through the white matter, the latter fibers performing a diverse function. Since 1977, the Laboratory was headed by Prof. V. A. Otellin, since 1980, by Medical Sciences Doctor F. N. Makarov. Dr. F.N.Makarov with co-workers

Investigations of the Laboratory acquired a functional-morphological direction, scientific connections with physiological and clinical laboratories and institutes become closer. The number of complex, interdisciplinary studies increased. Peculiarities of brain histohematic and histoliquor barriers have been studied. It has been established that owing to intercellular gaps, all barriers at the borders of the media can be united into the single system regulating homeostasis of the organism internal medium.

For the first time, using electron-microscopy analysis, there were revealed regularities of structural specialized contacts of different types of glia (Muller glia, astrocytes, and oligodendrocytes) with the axonal surface of retinal ganglion cells throughout its entire length from cellular soma to synaptic terminals in the lateral geniculate body.

A concept of the Muller glia isolating function under conditions of non-myelinated medium in the retina was formulated. The astrocyte and Muller cell glial membrane are closely adjacent to the surface of axon and regulate ion flows across the external membrane by decreasing resistance around the ganglion cell soma. It is suggested that the distal part of the initial axon segment, which is surrounded by the glial crown , is the site of the appearance of spikes in the ganglion cells.

Ultrastructural organization of the eye area cribrosa was studied. In a comparative-morphological investigation with use of light and electron microscopy the existence of a partial block of the axonal transport (both ortho- and retrograde) in the area cribrosa part in many representatives of mammals and in human under conditions of normal intraocular pressure. It is suggested that the established existence of chronic traumatization of the optic nerve axons in the normotensive eye can be a predisposing factor for development of glaucoma.

A quantitative analysis has been performed of morphological cluster organization of initial neurons in the fields 17 and 18 of visual cortex, which form interzonal ipsilateral connections with the field 21a. Based on description of quantitative and vector characteristics of distribution of cells, clear and reliable differences were revealed in distribution of clusters in the fields 17 and 18. The obtained data are of essential significance for detailed description of the complex construction of internal cortical connections of the visual cortex, which is caused by anisotropy of retinotopical magnification. Based on the differences in the spatial construction of neuronal connections in cortical columns of the cat brain field 17 and 18, for the first time there were established consecutive stages of formation of the three-dimensional reflection of visual objects: (1) combination of visual semifields of each eye (internal and interhemispheric connections), (2) identification of visual space loci and their integration in the stereoscopic surface (efferent connections with the fields 19 and 21). The obtained data are important for understanding of structural bases of the process of binocular stereosynthesis and for creation of model algorithms during design of technical systems for visual recognition.

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