Gustatory stimulation influences the processing of intranasal stimuli

Objectives: Taste and smell interact. The aim of this study was to examine this interaction using gustatory and olfactory stimuli applied at the same time, which exhibited perceptual compatibility and incompatibility. Methods: Thirty-two, young, healthy normosmic subjects (16 men, 16 women) took part in two randomized sessions. Event-related potentials (ERP) were recorded in response to vanillin, or gaseous CO2. These two conditions were combined with three taste conditions including sweet taste, sour taste, and the intraoral presentation of an empty taste dispenser. Results: Vanillin responses were largest for the sweet condition, while they were smaller for the sour condition. In contrast, responses to CO2 were largest under the sour condition, and smallest under the sweet condition. Moreover, during the sweet condition the latencies of P1 and N1 were shorter than in the sour condition, which was the other way around for CO2. Conclusions: Results of the present investigation suggested that (1) the early processing of intranasal chemosensory stimuli is modulated through concomitant gustatory stimulation, and that (2) this modulation may depend, at least in part, on the contextual compatibility between intranasal and intraoral stimuli. (c) 2005 Elsevier B.V. All rights reserved.