How images of food become cravingly salient in obesity

Abstract

AbstractObjectiveThis case‐control study was aimed at testing two main hypotheses: (i) obesity is characterized by neurofunctional alterations within the mesocorticolimbic reward system, a brain network originating from the midbrain ventral tegmental area (VTA); and (ii) these alterations are associated with a bias for food‐related stimuli and craving.MethodsNormal‐weight individuals and individuals with obesity underwent a resting‐state functional magnetic resonance imaging scan and the assessment of impulsivity, food craving, appetite, and implicit bias for food and non‐food stimuli. The VTA was used as a seed to map, for each participant, the strength of its functional connections with the rest of the brain. The between‐group difference in functional connectivity was then computed, and brain‐behavior correlations were performed.ResultsIndividuals with obesity showed hyper‐connectivity of the VTA with part of the ventral occipitotemporal cortex, recently found to be specialized for food images, and hypo‐connectivity with the left inferior frontal gyrus, devoted to cognitive control. VTA–ventral occipitotemporal cortex connectivity was positively associated with food craving and food‐related bias; the reverse correlation was observed for VTA–inferior frontal gyrus connectivity.ConclusionsThese findings reveal that, in obesity, food‐related visual stimuli become cravingly salient through an imbalanced connectivity of the reward system with sensory‐specific regions and the frontal cortex involved in cognitive control.