Turns Out Some Smells May Be Processed in the Same Brain Area as Taste
We tend to think of the brain as a collection of specialized regions: the frontal lobe handles decision-making, the amygdala processes emotions, and the occipital lobe translates vision. But most everyday impressions require multiple regions working in sync, making perception a complex neurological effort.
Take something as simple as tasting a strawberry. Telling it apart from other sweet fruits requires input from more than just the tongue. Flavor recognition needs both nose and taste buds, yet exactly where in the brain this information comes together has been unclear.
Scientists at Sweden’s Karolinska Institutet recently got a better look. By scanning participants’ brains while exposing them to sweet and salty samples, they discovered that certain aromas are processed much like actual tastes.
Read More: When Taste and Smell Disappear for Good
Taste Buds and Smell Receptors
Our tongues can only distinguish five basic tastes: sweet, sour, salty, bitter, and umami. That’s hardly enough to capture the complexity of a curry or a glass of wine. To identify what we’re eating, our noses step in.
When we chew, food releases aromatic compounds that travel through the back of the throat to the smell receptors in the nose (retro nasal odor). This information combines with taste signals in the brain — and flavor is born.
That’s why food seems dull when we have a cold. The taste buds still function, but the flow of aromas is blocked. What hasn’t been clear is where and how the brain merges these inputs into the rich experience we call flavor.
Aroma Processed in the Taste Cortex
In a study published in Nature Communications, the Karolinska team invited 25 healthy adults to explore this mystery. Participants were given two flavored solutions, one salty and one sweet, each combining taste with aroma.
They then underwent functional magnetic resonance imaging (fMRI) while receiving either a tasteless aroma or a taste without smell. Using a trained algorithm, the researchers saw that when participants inhaled only aromas, their brain’s taste centers lit up, showing patterns similar to those triggered by actual tastes.
This means aromas can be processed directly in the insula, a brain region that integrates sensory, emotional, and cognitive information, before moving on to the frontal cortex, the actual ‘smell center.’ The insula, in other words, may be doing more of the flavor heavy lifting than previously thought.
Understanding How Eating Habits Form
“The finding provides a possible explanation for why we sometimes experience taste from smell alone, for example, in flavored waters,” said lead author Putu Agus Khorisantono, a researcher at Karolinska’s Department of Clinical Neuroscience, in a press statement. “This underscores how strongly odors and tastes work together to make food pleasurable, potentially inducing craving and encouraging overeating of certain foods.”
Co-author Janina Seubert added that the brain seems to process taste and smell jointly rather than separately, as once believed. “This mechanism may be relevant for how our taste preferences and eating habits are formed and influenced,” she explained in the press release.
Looking ahead, the team wants to see how the process differs when smells come from the external environment (ortho nasal odors) rather than from the mouth. One real-world scenario they’d like to explore: does the brain’s taste cortex shift from salty to sweet activation as we walk from the cheese aisle to the pastry section of a supermarket?
Read More: How to Improve Your Sense of Smell and Taste
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