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

ABSTRACT

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.