The piriform cortex in the mammalian brain is the largest cortical region that receives direct sensory input from the olfactory bulb as well as complex top-down inputs from higher brain regions. It is located in the ventral part of the brain, right behind the olfactory bulb and above the eyeball. While this heterogeneous brain region is composed of many subregions, the overall roles assigned to the piriform cortex are the integration of elementary odor information and the association of this representation with other sensory and task variables (such as spatial location or context). Most frequently, the piriform cortex is seen as encoding odor identity in distributed ensembles of neurons. Whether and how this encoding evolves during learning and experience is not well characterized or understood.
