Ovarian hormones act to differentially impact choice for sexual and feeding behavior at the same time in operant choice paradigm

Abstract

Motivation is what drives animals to choose which stimuli to engage in out of the hundreds of choices they are faced with daily. In terms of sexual behavior, the motivation for females to engage in copulatory behavior apart from their ability to do so is not well studied. Further, the impacts of estradiol on the motivational aspects of sexual and feeding behavior have not been tested in a lab setting. Here, Becker Lab scientists have developed a novel paradigm to study the motivational aspects of female sexual motivation apart from the consummatory aspects of physical mating behaviors. Ovariectomized female rats were trained on an FI15s operant conditioning schedule to nose poke for palatable food pellets or access to a sexually receptive male within the same apparatus. Males were tethered to one side of the apparatus, allowing females to have free range and control the pace of mating interactions. Results showed that when primed with injections of estradiol benzoate and progesterone, females made more responses for access to a sexually receptive mate than for palatable food pellets. Oppositely, females made more responses for pellets when unprimed, and less responses for access to a mate. Females made the same amount of effort across all trials, indicating that circulating levels of estradiol increase the incentive value for cues associated with a male while at the same time decrease the incentive value for pellet cues.