Further steps in the research of cortico-hypothalamic interactions in cats

The cerebral cortex of the cat was systematically stimulated with electric shocks, and the recording of the evoked potentials in the hypothalamus was performed with macro- and microelectrodes stereotaxically guided. Stimulation of definite cortical loci evoked potentials in several hypothalamic nuclei studied. Three focuses were found, coincident with the so called "primary sensory area" of the neocortex. Hypothalamic responses elicited by stimulation of the ipsilateral cortex have greater amplitude and shorter latency than those evoked by contralateral stimulation. The "uconditioning" stimulus given on the cortex produces on the "test" stimulus response an inhibitory effect if the interstimulus delay is shorter than 0.6 sec, and a facilitatory if it is greater than 0.6 sec.