Abstract
Grounded theories of cognition claim that the neural substrates involved in object perception support both the perceptual and conceptual processing of those objects. Thus, the conceptual representation of food should involve brain regions associated with taste perception. This idea is supported by previous human neuroimaging research showing that viewing pictures of food (vs. non-food objects) activated taste-responsive regions of the insular cortex, thus suggesting that these pictures trigger an automatic retrieval of taste property information associated with the depicted foods. While suggestive, these findings do not indicate whether these representations contain specific information about the taste qualities of the depicted foods (i.e. whether a food is predominantly sweet, sour, or salty). To explore this question, we examined food-related responses within the human brain using ultra-high resolution functional magnetic resonance imaging (MRI) at high magnetic field strength (7-Tesla). During scanning, participants tasted sweet, salty, sour and tasteless liquids, delivered via a custom-built MRI-compatible tastant-delivery system. In a separate task, subjects also viewed pictures of a variety of sweet, salty, and sour foods, as well as non-food objects. As previously observed, all tastes (vs. tasteless) activated gustatory cortex within the dorsal mid-insula, a region also activated when subjects viewed pictures of food (vs. non-food objects). Using multivoxel pattern analysis, we were able to decode the taste category associated with these food pictures within this mid-insula region as well as from a region of oral somatosensory cortex. A multivariate searchlight analysis also decoded the picture-associated taste category in orbitofrontal cortex and the amygdala - regions located downstream in the taste pathway. These results suggest that these food representations, located within the neural structures involved in taste perception, contain information specific to the sensory qualities of visually depicted foods.