| Abstract: | Responses of pyramidal tract neurons and corticorubral and unidentified neurons in the pericruciate area of the cortex to electrical stimulation in the posterior, tuberal, and anterior zones of the lateral hypothalamus and also to electrodermal stimulation of all four limbs were studied in cats anesthetized with chloralose. The proportion of pyramidal tract, corticorubral, and unidentified neurons which responded to hypothalamic stimulation was 73.3, 55.7, and 79.1% respectively. Data on the possibility of monosynaptic activation of some pyramidal tract neurons and unidentified cells were obtained. The presence of less stable and longer-latency responses of corticorubral neurons indicated the absence of a monosynaptic pathway for realization of ascending hypothalamic influences on neurons of the cortical extrapyramidal system. Some cortical neurons responded to stimulation of more than one zone of the hypothalamus. Pyramidal tract neurons and corticorubral neurons with axon collaterals running into the region of the hypothalamus were discovered for the first time. It was shown that most neurons of the pericruciate area of the cortex to which the ascending influence of the hypothalamus is directed have a large bilateral receptive field and respond to electrodermal stimulation of several limbs.L. A. Orbeli Institute of Physiology, Academy of Sciences of the Armenian SSR, Erevan. Translated from Neirofiziologiya, Vol. 14, No. 3, pp. 298–306, May–June, 1982. |
