Insula to ventral striatal projections mediate compulsive eating produced by intermittent access to palatable food

Compulsive eating characterizes many binge-related eating disorders, yet its neurobiological basis is poorly understood. The insular cortex subserves visceral-emotional functions, including taste processing, and is implicated in drug craving and relapse. Here, via optoinhibition, we implicate projections from the anterior insular cortex to the nucleus accumbens as modulating highly compulsive-like food self-administration behaviors that result from intermittent access to a palatable, high-sucrose diet. We identified compulsive-like eating behavior in female rats through progressive ratio schedule self-administration and punishment-resistant responding, food reward tolerance and escalation of intake through 24-h energy intake and fixed-ratio operant self-administration sessions, and withdrawal-like irritability through the bottle brush test. We also identified an endocrine profile of heightened GLP-1 and PP but lower ghrelin that differentiated rats with the most compulsive-like eating behavior. Measures of compulsive eating severity also directly correlated to leptin, body weight and adiposity. Collectively, this novel model of compulsive-like eating symptoms demonstrates adaptations in insula-ventral striatal circuitry and metabolic regulatory hormones that warrant further study

Animal Models of Eating Disorders

Eating disorders (EDs) include a range of chronic and disabling pathologies characterized by persistent maladaptive eating habits and/or behaviors aimed at controlling body shape and size, with important consequences on physical health. Different animal models of EDs have been developed to investigate pharmacological, environmental, and genetic determinants that contribute to the development and maintenance of these disorders as well as for the identification of potential therapeutic targets. In this chapter, we will provide an overview of the most useful animal models of EDs, focusing mainly on those used to study anorexia nervosa and binge eating disorder