autosexual and social behavior of adult male
rhesus monkeys with medial preoptic-anterior
Slimp JC, Hart BL, Goy RW.
Bilateral radiofrequency lesions were made
in the medial preoptic-anterior hypothalamic
(MP-AH) area of 6 adult male rhesus monkeys; 5
sham-lesioned subjects served as controls.
Behavioral analysis consisted of
observations on copulatory behavior, yawning,
masturbation and some aspects of social
behavior. MP-AH lesions reduced or completely
eliminated the display of manual contacts of the
partner, mounts, intromissions and ejaculations
without interfering with masturbation.
Yawning, a sexually dimorphic behavior,
was not affected either, Measure of several
social behaviors indicated no evidence of social
withdrawal or other aberrance of social
interactions, which might have led to the
decline in heterosexual behavior.
The results with regard to copulatory
behavior were consistent with the effects of
MP-AH lesions in rats, cats and dogs. In rhesus
monkeys it appears as though the MP-AH region is
specifically involved in the mediation of
heterosexual copulation and is not vital to the
performance of other forms of male sexual
activity such as masturbation.
Also the MP-AH is not critical for the
display of all sexually dimorphic behaviors. The
types of behavioral change in MP-AH lesioned
subjects differed to some extent from those
following castration, indicating that the
effects of the lesions cannot be explained as
basically that of functional castration.