Smell: Central nervous processing

This chapter focuses on central olfactory processing in the human brain. As the psychophysiology of human olfactory function is important for appreciating its underlying neurophysiology, the chapter will begin with a brief overview of what the human nose can do, contesting notions that human olfaction is a second-rate system. It will be followed by an anatomical survey of the principal recipients of olfactory bulb input, with some comments on the unique organizing properties that distinguish olfaction from other sensory modalities. The final section will cover the neural correlates of human olfactory function, including aspects of basic chemosensory processing (odor detection, sniffing, intensity, valence) and higher-order olfactory operations (learning, memory, crossmodal integration), with particular emphasis on functional imaging data, though human lesion studies and intracranial recordings will also be discussed.