Chemosensory convergence on primary olfactory cortex

Abstract

Food perception and preference formation relies on the ability to combine information from both the taste and olfactory systems. Accordingly, psychophysical investigations in humans and behavioral work in animals has shown that the taste system playsan integral role inodor processing. However, the neural basis for the influenceof taste (gustation)on odor (olfaction) remains essentially unknown. Herewetested the hypothesisthat gustatoryinfluenceonolfactoryprocessing occursatthe levelofprimaryolfactory cortex.Werecorded activity from single neurons in posterior olfactory (piriform) cortex (pPC) of awake rats while presenting basic taste solutions directly to the tongue. A significant portion of pPC neurons proved to respond selectively to taste stimuli. These taste responses were significantly reduced by blockade of the gustatory epithelium, were unaffected by blockade of the olfactory epithelium, and were independent of respiration behavior.Incontrast, responsestoolfactory stimuli, recorded from the same area, were reducedby nasal epithelial deciliation and phase-lockedtothe respiration cycle. These results identify pPCasalikely site for gustatory influenceson olfactory processing, which play an important role in food perception and preference formation. © 2012 the authors.