[Reactions of hypothalamic neurons to stimulation of the pelvic and sciatic nerves]

Unit activity of posterior, tuberal and anterior parts of the hypothalamus was studied during stimulation of the pelvic nerve in anesthetized and immobilized cats. Comparative analysis showed that neurons of the posterior hypothalamus were more responsive (89.6%) and had a shorter mean latency (33.3 +/- 2.4 msec) than neurons of more rostral parts of the hypothalamus. The focus of maximal pelvic-induced unit activity seems to be located in the posterior hypothalamus. The unit responses of the posterior hypothalamus evoked by pelvic nerve stimulation had long recovery cycles and were suppressed at low frequencies of stimulation. These findings suggest a polysynaptic organization of pelvic afferent projection in the hypothalamus. A high degree of convergence of the visceral and somatic afferent signals onto single neurons was found during stimulation of pelvic and sciatic nerves. The functional role of neurons of integrative types is discussed.