How do tastants evoke hardwired behavior?

The taste system evaluates the nutritional value (sweet, umami, salty) and safety (bitter, sour) of food. Because this assessment is critical for the survival of the animal, taste cues immediately cause stereotypical behaviors (attraction vs aversion) and evoke innate affect (pleasure vs disgust). In spite of Ramón y Cajal having mapped medullary connections more than a hundred years ago, our current understanding of the brainstem circuits is still limited to the gross anatomical ‘nucleus’ level, and specific information about molecules and cells in the brainstem is lacking. Our long-term plan is to map and manipulate brainstem circuits.