Some characteristics of the afferent flow during noxious stimulation of the skin

Abstract

High-frequency electrical stimulation of the-posterior hypothalamus applied 10-20 days after the sectioning of the brain stem at the level of the anterior frontal margins of the anterior coliculus results in the preferential activation of the ipsilateral neocortex. When unilateral lesions are placed in the posterior hypothalamus, the predominance of synchronous activity in the ipsilateral neocortex is observed. In the premesencephalic preparations, weak single electrical stimulation of the posterior hypothalamus provokes spindles in the ipsilateral portions of the frontal cortex. At more intensive single stimulation of the posterior hypothalamus there occurs diffuse appearance of spindles in different neocortical areas. Besides the preferential unilateral effect, the influence of the posterior hypothalamus is more prominent in the frontal than in the occipital regions of the cortex. It is suggested that the posterior hypothalamus exerts its influence on the neocortex through the thalamic nuclei.