Figure 1.

Regulation of food intake by negative valence and positive valence appetitive systems, visceral aversive pathways, and the relationship with homeostatic deficit. Negative valence appetitive systems (e.g., AGRP neurons) are under homeostatic control, but AGRP neurons are rapidly inhibited by cues that predict food, thus consumption is associated with the positive valence system. Positive valence-driven eating (e.g., via the lateral hypothalamus) is modulated by energy deficit but also maintains appetite irrespective of a homeostatic need state. Aversive visceral signals, with different motivational properties than negative valence AGRP neurons, are activated by visceral and hormonal satiety signals and lead to cessation of food consumption. Interactions between these systems exist but are not shown.