Mapping brain activity induced by olfaction of virgin olive oil aroma

The difficulty of explaining sensory descriptors of virgin olive oil aroma by the analysis of volatile compounds is partially due to the subjective opinions of panelists and the lack of information of the neural mechanisms that ultimately produce a sensory perception. In this study the technique of functional magnetic resonance imaging (fMRI) has been applied to study brain activity during the smelling of virgin olive oil of different qualities. The volatile compounds of the samples were analyzed by solid-phase microextraction gas chromatography to explain the differences in the aromas presented to the subjects during the fMRI experiments. Comparing the pleasant and unpleasant aromas, the most evident differences in brain activity were found at the anterior cingulate gyrus (Brodmann area 32) and at the temporal lobe (Brodmann area 38). The activations were also observed when subjects smelled dilutions of heptanal and hexanoic acid, both compounds being responsible for off-flavors. Other areas were inherent to the olfaction task (e.g., Brodmann area 10) and to the intensity of the aroma (Brodmann area 6).