[Connections between area AIV and areas AI, AII and Ep of the auditory cortex in the cat]

Zones AI A11 and Ep in the cat auditory corex have been studied layer-by-layer electron microscopically after the zone AIV has been removed. Terminals having degeneration signs according to the dark type are mainly found in the layers V-VI of all the auditory cortex zones studied. Additional degenerative zones are revealed in the layer I of the zone AII and in the layer II of the zone Ep. Not any additional foci of degeneration are found in the zone AI. A suggestion is made concerning a physiological significance of the afferent distribution in the connective systems investigated. The corticocortical connections are formed by axodendritic and axospine synapses.