Lesions of the Medial Prefrontal Cortex Cause Maladaptive Sexual Behavior in Male Rats

Background: An inability to inhibit behaviors once they become maladaptive is a component of several psychiatric illnesses, and the medial prefrontal cortex (mPFC) was identified as a potential mediator of behavioral inhibition. The current study tested if the mPFC is involved in inhibition of sexual behavior when associated with aversive outcomes. Methods: Using male rats, effects of lesions of the infralimbic and prelimbic areas of the mPFC on expression of sexual behavior and ability to inhibit mating were tested using a paradigm of copulation-contingent aversion. Results: Medial prefrontal cortex lesions did not alter expression of sexual behavior. In contrast, mPFC lesions completely blocked the acquisition of sex-aversion conditioning and lesioned animals continued to mate, in contrast to the robust behavioral inhibition toward copulation in mPFC intact male animals, resulting in only 22% of intact male animals continuing to mate. However, rats with mPFC lesions were capable of forming a conditioned place preference to sexual reward and conditioned place aversion for lithium chloride, suggesting that these lesions did not alter associative learning or sensitivity for lithium chloride. Conclusions: The current study indicates that animals with mPFC lesions are likely capable of forming the associations with aversive outcomes of their behavior but lack the ability to suppress seeking of sexual reward in the face of aversive consequences. These data may contribute to a better understanding of a common pathology underlying impulse control disorders, as compulsive sexual behavior has a high prevalence of comorbidity with psychiatric disorders and Parkinson's disease.