Sex differences in extinction of Pavlovian food cues

Food-associated memories are fundamental to our survival. Learned food cues guide food-seeking and eating behaviors. How long these memories persist varies across individuals. In some people, enduring food memories become maladaptive and cause sustained cravings and disordered eating. Women are more susceptible than men to obesity, eating disorders, and addiction, and yet, memory and extinction of food cues have not been systematically examined in both sexes. Here, we compared adult male and female rats during cue-food acquisition, extinction, and renewal or reacquisition in three experiments with Pavlovian conditioning. Extinction is context-specific, and there are sex differences in context-dependent renewal of responding after extinction. The first two experiments tested whether pretraining habituation to the learning and extinction contexts (with or without food reward) would improve renewal in both sexes. Habituation did not improve renewal in either experiment. Unexpectedly, females showed impaired extinction. The third experiment utilized a test of extinction resistance: the partial reinforcement extinction effect. In this task, females showed pronounced resistance to extinction compared to males, especially when learning and extinction occurred in the same context. These findings point to differences in extinction as the potential cause of individual differences in persistent cue-driven food cravings and the inability to alter eating behaviors.