The effect of medial amygdala lesions on instrumental sexual responses in male rats

Abstract

In male rats bar press responses reinforced by the contact with estrous females were established during the preoperative training. Bilateral electrolytic lesions of the medial amygdala nuclei caused an impairment of copulatory behavior manifested by the appearance, during male-female contacts, of exploratory behavior or body investigation instead of copulatory behavior. In all subjects such noncopulatory contacts occurred alternately with those when the copulations took place. The latencies of instrumental responses immediately following the contacts during which intromissions took place remained unchanged. It is suggested that the medial amygdala exerts excitatory and regulatory influences on sexual arousal mechanisms in male rats.