Olfactory event-related potentials in response to ortho- and retronasal stimulation with odors related or unrelated to foods

The aim of this study was to investigate the perception of odor intensity following ortho- and retronasal odor presentation and to simultaneously study differences between ortho- and retronasal olfaction using an electrophysiological measure event-related potentials (ERP). Using air-dilution olfactometry, 24 young healthy subjects were investigated. For retro- and orthonasal stimulation, a technique was used that allowed precise control of stimulus characteristics. To investigate potential distinctions between the processing of food and non-food related odors, lavender and chocolate odors were used. Results indicated that, when an odor unrelated to food was presented in an unusual site, i.e., retronasally, the response was larger compared with presentation of the same odor at an orthonasal site. This was the other way around for a food-related odor. These changes indicate differences of information processing depending on the context and the route of odor presentation which has direct implications for the enjoyment of foods and drinks.