A Satellite Symposium, 3rd Congress of International Brain Research Organization.
NEURAL BASIS OF PRESENTING AND ALLOGROOMING IN THE MONKEY: UNIT RECORDING AND ELECTRICAL STIMULATION STUDIES
S. Aou, Y. Oomura, H. Yoshimatsu, I. Fujita, Y. Koyama and H. Nishino,
National Inst. Physiol. Sci., Okazaki 444; Dept. of Physiol., Fac. Med., Kyushu Univ. 60, Fukuoka 812; Dept. of Physiol., Toyama Med. and Pharmaceut. Univ., Toyama 930-01, Japan
Although presenting and allogrooming are major components of social/sexual behavior in primates, still little is known about neural mechanisms underlying these behaviors. In the present study, we recorded neuron activity of the preoptic area and the hypothalamus during presenting and allogrooming using three female and two male macaque monkeys. Effects of electrical stimulation of these areas on the behaviors were also investigated. About 50% of female ventromedial hypothalamic neurons showed activity changes, mainly increase, during presenting. Single train stimulation (rectangular pulses of 0.5 ms duration, <500 uA, 50 Hz, 2.5 sec) of this area elicited presenting only when a male partner was in near position. In the female medial preoptic area (MPOA), 85% of neurons showed changes in their activity during presenting with copulation, while only 40% of neurons responded, mainly with firing decrease, during presenting without accompanying mating acts of the male. Repetitive but not single train stimulation of the MPOA elicited presenting. Male's mating acts enhanced activity changes in more than half of the neurons tested in both areas. Stimulation of the lateral preoptic area, lateral hypothalamic area or dorsomedial hypothalamic nucleus, where allogrooming-related activity changes were found, elicited allogrooming in both sexes. These findings indicate that different neuronal groups in the preoptic area and the hypothalamus are involved in facilitatory control of presenting and allogrooming.