[Participation of hypothalamic formations in regulation of the neuronal activity of rabbit visual cortex].

Electric stimulation of different hypothalamic nuclei was used during the effect of extracellular polarizing current on neurons of the rabbit optic cortex. It was found that stimulation of the hypothalamus caused a decrease in the medium rate of impulsation of a great number of studied optic cortex neurons under conditions of anodic polarization when the background level of activity was considerably enhanced. The same stimulation increased the activity under conditions of cathodic polarization when the initial level of the activity was considerably lowered. The same tendency to restore the initial (background) level of the neuronal activity after hypothalamic stimulation was observed under conditions when this level was shifted by application of rhythmic light. The greatest effect was observed during stimulation of the preoptic region. Stimulation of the posterior hypothalamic nucleus was less effective in this respect.