The taste system encodes stimulus toxicity.

Attempts to define the organization of the taste system in terms of the physical characteristics of stimuli have been largely unsuccessful. We recorded taste-evoked neural activity in the rat's hindbrain and determined that stimuli could be effectively organized along a physiological dimension which corresponds to stimulus toxicity. Taste is a visceral sense that mediates between the external and internal chemical environments. Its responsiveness to a wide range of chemicals and its organization along a dimension which promotes the organism's physiological welfare ideally suit it to that purpose.