A Pavlovian procedure for improving sexual performance of noncopulating male rats

Previous research has shown that Pavlovian conditioning, based on unconsummated arousal, can increase copulatory rate in laboratory rats. This investigation tested whether a similar procedure could improve the performance of males that initially fail to copulate successfully. Male rats that did not reach ejaculation with a receptive female on a pretest were randomly assigned to one of two groups: CS-US paired or CS-US unpaired. The CS consisted of a period of placement in a running wheel which allowed measurement of incidental activity. The US was (arousing) exposure to a female separated from the male by a wire mesh screen. The CS immediately preceded the US for the paired group but the two were unpaired for the control group. Following conditioning, CS and No-CS tests were given, with both copulation and activity measures taken. Subjects in the paired group were significantly more likely to achieve ejaculation on the CS test than those in the control group, and they were also more active during the test. In contrast, differences on the No-CS test were not significant, consistent with expectations from a Pavlovian explanation. These data show the efficacy of Pavlovian procedures in improving sexual performance, with a possible application to increase arousal to selected cues for human subjects, e.g., some individuals with erectile dysfunction.