Is It a Taste or a Smell?

You've probably heard before that much of what you "taste" is actually determined by your nose. Now, new research from Yale University and the University of Dresden Medical School shows that not only are smell and taste inextricably intermingled, but smells stimulate different parts of the brain when they are experienced through the nose versus through the mouth

"The role of olfaction [sense of smell] in taste is powerful," the researchers wrote in the journal Neuron. "For example, we may say that we like the 'taste' of wine, because of its fruity or spicy notes. However, gustation [sense of taste] refers only to the sensations of sweet, sour, salty, savory and bitter, and thus the pleasant 'taste' to which we refer is actually a pleasant odor sensed retronasally [through the mouth]."

To test how the brain reacts differently when smells are experienced through the mouth versus through the nose, the researchers inserted small tubes into the nostril passages and nasal passages near the throat of test subjects. They then watched the subjects' brain patterns while the odors of chocolate and lavender, among others, were introduced through the nostrils and then through the mouth.

The chocolate odor stimulated different regions of the brain depending on whether it was experienced through the mouth or the nose. The lavender scent showed a similar effect but to a far lesser extent than the chocolate.

The researchers theorize that odors from food, such as chocolate, elicit particular responses associated with eating when experienced through the mouth as opposed to the nose but that those differences are much less pronounced for non-food odors.

"It is possible that the route of stimulation may have different effects for food versus non-food odors," the researchers concluded.

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