2023-2024 CNLM Colloquium Series

Reward is often present in risky environments, requiring individuals to weigh the benefits of rewards against the associated risks. There are individuals that are unable to choose an appropriate response during risky reward opportunities and thus exhibit extreme avoidance or risky behaviors that can severely impair quality of life or endanger people. It is therefore necessary to characterize how neurons mediate reward approach and threat avoidance conflict. Here, we adapted the platform-mediated avoidance conflict task (Bravo-Rivera et al 2014; Bravo-Rivera et al 2021), such that water-deprived mice could nose-poke for a light-signaled water reward and avoid a tone-signaled foot-shock by stepping onto a safety platform away from the reward port. Optogenetic activation of GABAergic neurons in the ventral pallidum invigorated reward approach at the expense of receiving shocks. Photometry recordings of glutamatergic neurons in the ventral pallidum and in the lateral habenula during conflict revealed that these structures promote avoidance and become inhibited during conflicted reward approach. These results suggest that a pallidal-habenula circuit mediates motivational conflict. We also compared behavioral conflict in male and female mice. Interestingly, females stepped on the platform earlier than males after tone onset and took longer to leave the platform after tone offset. Males received more shocks than females and received more water reward than females by the end conflict training. Moreover, females exhibited more tone-induced freezing and exhibited more frequent darting than males. These results suggest that females exhibit more avoidance behavior and less reward approach than males in the face of approach/avoidance conflict.