Effect of single stimulation of the posterior hypothalamus on visual evoked potentials in anesthetized rabbits.

During single stimulation of the posterior hypothalamic nuclei an evoked hypothalamo-cortical response with a short latent period, well-marked primary positive and negative components, and a secondary positive wave of high amplitude was recorded in the visual cortex of rabbits anesthetized with pentobarbital. It is postulated that pathways from the posterior hypothalamus to the cortex are numerous, pass through various subcortical structures, and terminate in different synaptic organizations. Single stimulation of the posterior hypothalamic nuclei at intervals of between 700 and 100 msec facilitate the visual evoked potential on account of an increase in its negative component. Besides facilitation of the visual response, during single stimulation of the posterior hypothalamic nuclei the zone of recording of the visual evoked potential is widened.