[Intracortical connections between fields 18 and 19 of the visual cortex of cat's brain]

To study electron microscopically intracortical connections between areas 18 and 19 in the visual cortex of the cat brain, the distribution of synaptic terminals in every lamina of these areas was investigated after dissection of their border as deep as the grey matter. Mainly axo-dendritic synapses in large, small dendrites and in spines degenerated according to "light" and "dark" types were subjected to degeneration. All the laminae of the cortex were stated to participate in the formation of overlapping intracortical connections of areas 18 and 19. The greatest nember of altered synaptic buds, however, were detected in the middle layers, that correlated the data of the light optic method (A. S. Iontov, 1961, 1962). To obtain more objective data on the number of intracortical fibrils connecting these areas, normal and altered synapses up to 100 units were counted in every layer. Uneven localization of intracortical connections in every layer and their different functional importance were demonstrated.