An fMRI study on the influence of sommeliers' expertise on the integration of flavor

Abstract

Flavors guide consumers' choice of foodstuffs, preferring those that they like and meet their needs, and dismissing those for which they have a conditioned aversion. Flavor affects the learning and consumption of foods and drinks; what is already well-known is favored and what is new is apprehended. The flavor of foodstuffs is also crucial in explaining some eating behaviors such as overconsumption. The "blind" taste test of wine is a good model for assessing the ability of people to convert mouth feelings into flavor. To determine the relative importance of memory and sensory capabilities, we present the results of an fMRI neuro-imaging study involving 10 experts and 10 matched control subjects using wine as a stimulus in a blind taste test, focusing primarily on the assessment of flavor integration. The results revealed activations in the brain areas involved in sensory integration, both in experts and control subjects (insula, frontal operculum, orbitofrontal cortex, amygdala). However, experts were mainly characterized by a more immediate and targeted sensory reaction to wine stimulation with an economic mechanism reducing effort than control subjects. Wine experts showed brainstem and left-hemispheric activations in the hippocampal and parahippocampal formations and the temporal pole, whereas control subjects showed activations in different associative cortices, predominantly in the right hemisphere. These results also confirm that wine experts work simultaneously on sensory quality assessment and on label recognition of wine.

Keywords: expertise; fMRI; flavor; olfaction pathways; taste; wine.

Figure 1

Example of activations involving flavor integration (from Table 2). Visible activations are left pars opercularis and left and right insula for controls during the taste phase, right and left anterior insula and right orbitofrontal cortex for controls during the after-taste phase, left insula for experts during the taste phase, orbitofrontal cortex and the associative occipital cortex for experts during the after-taste phase.

Figure 2

Beta-value averages for the areas involved in flavor, based on Table 2. For each area from a group, the average values are given for the experts Group (red) and the Controls group (blue). The error bars indicate standard error. All regions of interest are from the Controls group, except for the two marked with ^* which are taken from the experts.

Figure 3

Example of activations involving memory (from Table 3) for the contrast experts minus controls. Activations in green are obtained during the taste phase; those in orange are obtained during the after-taste phase. Visible activations are both in the amygdala/hippocampus complex (taste phase), parahippocampal gyri (right and left for the taste phase, right for the after-taste phase), occipital associative cortex (right during the taste phase, left during the after-taste phase).

Figure 4

Beta-values of the contrast experts minus controls calculated for the regions involved in memory. Two conditions are concerned, in green for the wine and in blue for water. The error bars indicate standard error. The regions marked with # are activated during the after-taste phase, the others during the taste phase.