Sexual reward induces Fos in the cerebellum of female rats.

The cerebellum is generally considered a neural structure specialized in motor control and recent imaging data suggest its role in sexual behavior. Herein, we analyzed the pattern of Fos immunoreactivity (Fos-IR) in the cerebellum of female rats allowed to pace copulation as a model of sexual reward in rodents. Ovariectomized, hormone-primed, sexually naïve females formed three groups: Pacing, Nonpacing and Control. Pacing occurred in arenas bisected by a middle divider that allowed only females to control sexual interaction with stud males. For nonpaced copulation the divider was removed, and control females were allowed to pace in chambers without a male. Fos-IR was analyzed in granule and Purkinje layers of the 10 cerebellar lobules, and in the fastigial deep nucleus (FDN). Results indicated that Pacing females expressed more Fos-IR in the granule layer compared to Nonpacing and Controls, and more Fos-IR in Purkinje compared to Nonpacing. No differences were observed in FDN. Such response cannot be explained with motor activity because Pacing females moved less in general. We discuss the role of the cerebellum and its connections in the sexual reward induced by pacing.