Combinatorial effects of odorants on mouse behavior

Abstract

Significance Odor detection in the mouse nose is mediated by ∼1,000 different odorant receptors (ORs) and 14 trace amine-associated receptors (TAARs). Different OR combinations generate different odor perceptions. However, a few TAARs are associated with innate odor attraction or aversion, suggesting they signal through hard-wired neural circuits resistant to combinatorial receptor inputs. Contrary to this prediction, we find that different ligands for a given TAAR can be attractive or aversive, or instead neutral. In addition, some attractive and aversive odorants block one another’s behavioral effects. Odor blocking can occur without receptor antagonism in the nose and can require sensory input from one receptor. Thus, innate odor-induced behaviors can be context-dependent and modulated by interactions in the brain among signals derived from different receptors.