The chemical senses

The orbitofrontal cortex (OFC) is described as secondary olfactory and gustatory cortex. This chapter reviews the location of chemosensory processing in the OFC as defined by anatomical and neurophysiological methods in nonhuman primates, and neuroimaging and lesion data in humans. The human neuroimaging data suggest that broader areas of the OFC are involved in chemosensory processing than would be predicted from a strict anatomical analysis of input from primary olfactory/gustatory cortex. The properties of chemosensory processing in the OFC are discussed in terms of the breadth of tuning of sensory cells, the role of hedonics, and the dynamic nature of coding (response to satiety). Issues of functional lateralization and medial vs. lateral distinctions in hedonic processing are also covered. Finally, topics related to multisensory integration are covered.