Sniffing out meaning: Chemosensory and semantic neural network changes in sommeliers

Abstract

Wine tasting is a very complex process that integrates a combination of sensa-tion, language, and memory. Taste and smell provide perceptual information that,together with the semantic narrative that converts flavor into words, seem to beprocessed differently between sommeliers and naïve wine consumers. We inves-tigate whether sommeliers' wine experience shapes only chemosensory proces-sing, as has been previously demonstrated, or if it also modulates the way inwhich the taste and olfactory circuits interact with the semantic network. Com-bining diffusion-weighted images and fMRI (activation and connectivity) weinvestigated whether brain response to tasting wine differs between sommeliersand nonexperts (1) in the sensory neural circuits representing flavor and/or(2) in the neural circuits for language and memory. We demonstrate that trainingin wine tasting shapes the microstructure of the left and right superior longitudi-nal fasciculus. Using mediation analysis, we showed that the experience modu-lates the relationship between fractional anisotropy and behavior: the higher thefractional anisotropy the higher the capacity to recognize wine complexity. Inaddition, we found functional differences between sommeliers and naïve con-sumers affecting the flavor sensory circuit, but also regions involved in semanticoperations. The former reflects a capacity for differential sensory processing,while the latter reflects sommeliers' ability to attend to relevant sensory inputsand translate them into complex verbal descriptions. The enhanced synchroniza-tion between these apparently independent circuits suggests that sommeliersintegrated these descriptions with previous semantic knowledge to optimize theircapacity to distinguish between subtle differences in the qualitative character ofthe wine.