Recent research finds the brain, not the tongue, is the source of taste.
Taste forms an important part of our daily lives, discriminating between what we like, and what we don’t like when it comes down to tasting food and drinks.
Our taste sensation is made up of 5 basic tastes, sweet, sour, bitter, salty and savory, and each these has evolutionary roots that helped our ancestors survive. When something sweet was consumed, it could be regarded as energy rich for the body and perceived as good, whereas something bitter might be a warning sign that intake is harmful.
Most of us associate our tongues with the ability to taste food, sending signals to our brain translating what we have tasted. But now our understanding of how our taste sensation works might be completely turned upside down by a new study.
Research by the Zuckerman institute at the Columbia University Medical Centre has used a novel technique to turn different taste sensations on and off. By targeting specific brain regions responsible for taste in mice, the research team could switch the perception of bitter and sweet on and off by manipulating certain brain cells in the responsible region.
The team used a technique called optogenetics, which allowed them to activate specific neurons (Brain cells) using laser light. They wanted to find out whether stimulating certain neurons within the mouse brain could allow the mice to perceive the taste of sweet or bitter, without the mouse tasting either one.
Yueqing Peng, Postdoctoral associate at the Zukerman institute describe what their team wanted to achieve:
“In this study, we wanted to know if specific regions in the brain really represent sweet and bitter. If they do, silencing these regions would prevent the animal from tasting sweet or bitter, no matter how much we gave them,” he said. “And if we activate these fields, they should taste bitter or sweet, even though they’re only getting plain water.”
This is exactly what the team found. They were able to make mice think they were tasting bitter or sweet whiles the animal was drinking water. The team stimulated the brain region responsible for sweet perception while the animal was drinking water, and observed behavioral responses like increased licking or a gagging reflex, that indicated whether the animal thought the water was sweet or bitter. This fascinating study opens the door towards understanding how taste sensation really works, and implications for human taste stimulation might not be so far ahead in the near future.
The research study was published online in Nature.