The piriform cortex has two major divisions with anatomically distinct organizations and functions. The anterior piriform cortex (APC) is better associated with determining the chemical structure of the odorant molecules and whereas the posterior piriform cortex (PPC) is best known for its strong role in categorizing odors and assessing similarities between odors (e.g. minty, woody, citrus are odors which can be distinguished via the PPC despite being highly-variant chemicals and in a concentration-independent manner).