[GABA-ergic structures in intact and chronically isolated association cortex of the cat brain (field 5)]

Distribution of GABAergic structures in intact and neuronally isolated associative cortex (field 5) of the cat was studied using histochemical GABA-transaminase reaction two and three weeks after isolation. An overwhelming majority of GABAergic fibres of the neuropile and synaptic terminals were found to be formed by axons of few GABAergic interneurons. Only a small portion of them belongs to afferent axons of the extracortical origin. GABAergic interneurons can be divided into short-axon ones, making contacts within the isolated slat, and long-axon neurons forming horizontal connections with more distant cortical neurons. GABAergic axons give numerous projections to the soma and proximal parts of dendrites of many pyramidal neurons, containing no GABA-transaminase, and of stellate neurons which are of GABAergic and non-GABAergic mediatory nature. It is suggested that the influence of some GABAergic neurons on the others may ensure intracortical spatial regulation of inhibitory processes.