Modeling a flavor’s path to our senses

Smell is closely linked to taste. We perceive flavor when we exhale food particles held in our airway, but the reason for this has been elusive.

An interdisciplinary Yale team recently set out to learn why and how sense of taste is tied to exhalation but not inhalation. Led by Gordon Shepherd, M.D., D.Phil., professor of neuroscience, the team used a computerized tomography (CT) scan of a healthy airway to create a 3D-printed model of the anatomy. Sending water and fluorescent particles through the model, researchers visualized the path air and food particles take when we breathe through our noses.

Inhaled air, they found, creates a barrier that keeps food particles from traveling to the lungs. Exhaled air, however, travels through a virtual cavity, where it picks up the odor particles and carries them out through the nostrils. The findings, published in Proceedings of the National Academy of Science in November, suggest humans may have adapted this pathway to sense whether food is safe without taking its aroma into the lungs.