[Effect of nonspecific thalamic nuclei on individual ensemble-forming loci in the visual cortex].

Electric stimulation of guinea pigs' medial thalamic nuclei (MT) creates in the area 17 of the visual cortex functional groups of excited neurones, located within the same structural columns as ensembles of neurones excited by flashes of diffuse light. Together with analogous effects of the MBRF stimulation, such results indicate a convergence of different non-specific influences on separate columns of the visual cortex. MT exert their initial and mainly activating influences on the lower, efferent layers, while MBRF, according to literary data, activates afferent, middle layers of the cortex. This points to the existence in the visual cortex of separate non-specific regulation of the input on the part of the reticular formation and of the output on the part of MT.