Central organization of a high-dimensional odor space.

Animals recognize groups and mixtures of odors as a unitary object. This ability is crucial to generalize known odors to newly encountered ones despite variations. However, it remains largely unknown how multitudes of odors are represented and organized in the higher brain regions to support odor object recognition. Here we discuss recent advances uncovering the population odor responses in the rodent piriform cortex and the Drosophila mushroom body, and highlight the emerging principles on the organization, mechanism, stereotypy, and experience-dependence of central odor representations.