Electrically evoked sexual behavior and neuronal activity of hypothalamus in male monkeys. Proceedings of the International Union of Physiological Sciences XVI: 240.
I. Fujita, Y. Koyama, H. Yoshimatsu, H. Nishino and Y., Oomura,
National Institute for Physiological Sciences, Okazaki 444, Japan.
To study roles of the hypothalamus in sexual behavior, the effects of electrical
stimulation of the hypothalamus were examined in male rhesus monkeys. The stimulating
electrodes were then used for recording single neuron activity during spontaneous
sexual behavior. Electrical stimuli (50 Hz, 2.5 sec) of 15-100μA to the preoptic
area (POA), dorsomedial and lateral hypothalamic areas (DMH and LH) elicited
'touching' to female's back and rump. Stronger stimuli of 150-500 μA in DMH,
LH and ventromedial hypothalamus (VMH) elicited 'mounting'. 'Grooming' were
elicited by stimuli to some loci in the LH and lateral POA. Neuronal activity
during sexual behavior differed among different parts of the hypothalamus.
For example, half of the medial POA neurons decreased their firing rate during
mounting, while 10 % increased and 40 % did not show any change. In contrast,
half of the DMH neurons increased their activity, while 10 % decreased and
40 % did not show any change. Activity of most (86 %) of VMH neurons were unchanged
during mounting. The results support the idea that different parts of the hypothalamus
play different roles in male sexual behavior.