[Functional interactions between the rabbit hypothalamus and neocortex]

In acute experiments on rabbits under chloralose-nembutal anaesthesia, studies have been made on the distribution and the pattern of the evoked potentials (EP) in neocortical structures of the brain cortex during electrical stimulation of different hypothalamic nuclei. It was found that during stimulation of the supramammilar area of the hypothalamus, the focus of maximum activity of cortical responses of the negative-positive configuration is localised in the median parts of precentral agranular region. During stimulation of the posterior hypothalamic area, the EP were of the positive-negative-positive type. Registration of the EP in different cortical layers during stimulation of the posterior hypothlamic nuclei showed that from 100 to 100 micrograms the amplitude of EP components decreases, whereas at the level of 600 mu the inversion of the EP takes place. At the depth of 1.800 mu the EP elicited by stimulation of the posterior hypothalamus had a form of a positive oscillation with a long latent period. It is concluded that the posterior hypothalamic nuclei have a vast representation in rabbit neocortex, this representation being realized by both polysynaptic and olygosynaptic systems of connections.