Conditioned Partner Preference in Male and Female Rats for a Somatosensory Cue

Male and female rats form a conditioned preference to copulate and/or mate with conspecifics bearing an odor that was paired with either the postejaculatory reward state in males, or paced sexual contact in females, making the odor act as a discrete partner-related cue. Here, we asked whether a somatosensory cue, a rodent jacket, could act as a discrete cue to establish a conditioned partner choice (CPC). In the first study, sexually naïve Long-Evans males and females underwent 14 copulatory conditioning trials for 30 min with their opposite sex partner in unilevel pacing chambers. On the final test, each experimental male or female was placed into an open field with two sexually receptive partners, one jacketed and the other unjacketed. A trend was found for more males to ejaculate first with jacketed females relative to the unjacketed females, whereas the females had no preference. Males and females in the second study were exposed sequentially to jacketed, sexually receptive partners, and unjacketed, sexually nonreceptive partners prior to a final open field test. Both males and females displayed a significant CPC for the jacketed opposite sex partner. This study demonstrates that a somatosensory cue previously used to establish sexual arousal as a contextual cue on rats can be used as a discrete, partner-based cue to establish a CPC for a particular partner wearing the jacket and that stronger conditioning occurs when the jacket is explicitly paired with the sexual reward state.