Binge eating is a problematic component of some forms of obesity, bulimia nervosa, and binge eating disorder (BED), For example, BED is a distinct eating disorder characterized by loss of control in eating behavior and is strongly associated with obesity and negative affect. Although mechanistic studies of binge eating have implicated the mesolimbic dopamine system and nucleus accumbens (Nacc), to our knowledge, no single unit electrophysiological studies have examined these neurons with respect to binge eating. In this proposal, using a well-established protocol that promotes binge eating, 20 female Sprague Dawley rats will be divided into binge eating (BE) and chow control (CC) groups. The BE group will be subjected to six weeks of a well- established paradigm involving binge eating of sweetened fat. After completion of the six weeks all animals will have a 16 microwire array implanted into the Nacc core and shell. Following surgery all animals will be subjected to ten daily sessions in a Pavlovian chamber where they will be trained to associate a tone cue with a sucrose reward. Analysis of single unit recordings as well as ultrasonic vocalizations (USV) during the trials will be performed. Preliminary analysis of cue evoked firing in pilot animals shows a medium effect size with regard to experimental group. There was a large effect of the directionality of change in neural firing with regard to the tone. Preliminary USV results indicate a fourfold increase in 50khz vocalizations in the pavlovian experiment when compared to baseline. Our results indicate that binge eating may have a strong effect on Nac responsiveness to food associated cues, which will be compared to the hypothesized increase in behavioral cue reactivity associated with binge eating.
Binge Eating (BE) is a component several eating disorders including Binge Eating Disorder (BED) and Bulimia Nervosa (BN). We plan to use electrophysiology, behavioral techniques, and ultrasonic vocalization to study a rat model of BE. In doing so, we will further our understanding of BE and therefore facilitate improvements in its treatment of related disorders. Finally, this research will provide valuable training for the applicant, so that he will be able to use these techniques throughout his future career as a medical scientist.