An Excitatory Projection from the Basal Forebrain to the Ventral Tegmental Area Underlying Anorexia-like Phenotypes

Abstract

Adaptation to potential threat cues in feeding regulation is key for animal survival. Maladaptation in balancing internal energy needs and external threat cues may result in eating disorders. However, brain mechanisms underlying such maladaptation remain elusive. Here, we identified that the basal forebrain (BF) sends glutamatergic projections to glutamatergic neurons in the ventral tegmental area (VTA). Glutamatergic neurons in both the BF and the VTA displayed correlated responses to various external stressors. Notably, in vivo manipulation of BF terminals in the VTA revealed that the glutamatergic BFVTA circuit reduces appetite, increases locomotion, and elicits avoidance. In consistence, activation of VTA glutamatergic neurons reduced body weight, blunted food motivation, and caused hyperactivity with behavioral signs of anxiety, all hallmarks of typical anorexia phenotypes. Importantly, activation of BF glutamatergic terminals in the VTA reduced dopamine release in the nucleus accumbens (NAc). Collectively, our results point to overactivation of the glutamatergic BFVTA circuit as a potential cause of anorexia-like phenotypes involving reduced dopamine release.