[A change in the spontaneous and evoked activity of rabbit visual cortex neurons upon stimulation of different regions of the hypothalamus].

The influence of stimulation of different hypothalamic areas on spontaneous and flash evoked electrical activity of visual cortex neurones was studied in acute experiments on rabbits by means of extracellular records. Stimulation of most parts of the hypothalamus depressed both kinds of neural activity. Stimulation of the ventro-caudal part of the lateral hypothalamic area and the supramammillar area alone resulted in a pronounced facilitation of the cortical unit activity. Localization of the facilitating areas coincides with the zones of maximum positive reinforcement in selfstimulation. The data are discussed in relation to the mechanisms of motivational behaviour.