Neurons and circuits for odor processing in the piriform cortex

• The piriform cortex (PC) is critical for olfactory processing in mammals.
• The PC is increasingly studied as a model circuit for cortical sensory processing.
• New work is providing detail on the cellular neurophysiology of the PC.
• We discuss microcircuits, inhibition, plasticity, and olfactory coding.

Increased understanding of the early stages of olfaction has lead to a renewed interest in the higher brain regions responsible for forming unified ‘odor images’ from the chemical components detected by the nose. The piriform cortex, which is one of the first cortical destinations of olfactory information in mammals, is a primitive paleocortex that is critical for the synthetic perception of odors. Here we review recent work that examines the cellular neurophysiology of the piriform cortex. Exciting new findings have revealed how the neurons and circuits of the piriform cortex process odor information, demonstrating that, despite its superficial simplicity, the piriform cortex is a remarkably subtle and intricate neural circuit.