Separable and integrated pleasantness coding for appetitive and aversive odors across olfactory and ventral prefrontal cortices

Odor pleasantness is a key driver of approach and avoidance behaviors, raising the question of how pleasantness is represented in olfactory brain areas. To address this question, here we analyzed an existing dataset consisting of perceptual and fMRI responses to 160 odors from three individual participants. We find that piriform cortex, amygdala, orbitofrontal cortex, and ventromedial prefrontal cortex encode the pleasantness of appetitive and aversive odors. However, whereas these pleasantness representations are separable for appetitive and aversive odors in piriform cortex and amygdala, ventral prefrontal cortex (especially area 11) combines information from appetitive and aversive odors and forms a continuous representation of odor salience. These results suggest that distinct pleasantness codes for appetitive and aversive odors in olfactory cortices are integrated into a continuous representation in ventral prefrontal cortices.