第1回国際ニューロエソロジー会議(東京)1986.9.


I. Fujita, Y. Koyama, H. Yoshimatsu, H. Nishino and Y. Oomura
Natl. Inst. Physiol. Sci., Okazaki 444, Japan.

We examined 1) the effects of electrical stimulation of the hypothalamus on sexual behavior in male rhesus monkeys and 2) the single neuron activity of this structure during spontaneous behaviors. Electrical stimuli of 15-100 μA in the preoptic area (POA), dorsomedial and lateral hypothalamic areas (DMH and LH) elicited "touching" to female's back or rump. Stronger stimuli of 150-500 μA in POA, DMH, LH and ventromedial hypothalamus elicited mounting with or without thrusting. Grooming was evoked by stimulation of 15-300 μA to some sites in LH and and lateral POA. Neuronal activity during sexual behavior varied among various nuclei. Half of the medial POA neurons decreased their firing rate during mounting, while 10 % increased and 40 % remained unchanged. In contrast, half of the DMH neurons increased their activity, while 10 % decreased and 40 % remained unchanged. The results indicate that various parts of the hypothalamus play different roles in male sexual behavior and that the lateral part of the hypothalamus is deeply involved in grooming. (Supported in part by a grant from Itoh Science Foundation)