Using optogenetic and chemogenetic techniques, researchers have identified brain circuits underlying hunger-induced changes in the preferences for sweet and aversive tastes in mice. These circuits involved Agouti-related peptide-expressing neurons, which projected to glutamate neurons in the lateral hypothalamus. From there, glutamate neurons projecting to the lateral septum increased sweetness preferences, and glutamate neurons projecting to the lateral habenula decreased sensitivity to aversive tastes.