The way in which we perceive taste, showing that four of our basic tastes-sweet, bitter, salty, and "umami," or savory-are processed by distinct areas of the brain has been unraveled in a new study.
Howard Hughes Medical Institute and NIH scientists found that each taste, from sweet to salty, is sensed by a unique set of neurons in the brains of mice.
The findings demonstrate that neurons that respond to specific tastes are arranged discretely in what the scientists call a "gustotopic map."
This is the first map that shows how taste is represented in the mammalian brain.
"This work further reveals coding in the taste system via labelled lines, and it exposes the basic logic for the brain representation of the last of the classical five senses," said Howard Hughes Medical Institute investigator Charles S. Zuker.
Zuker and Nicholas J. P. Ryba of the National Institute of Dental and Craniofacial Research observed that when a mouse is given something bitter to taste, or the receptors on its tongue that sense bitter are stimulated, many neurons in one small, specific area of the brain light up.
When the mouse is given something salty, an area a few millimetres away is activated. Each taste corresponded to a different hotspot in the brain.
None of the areas overlapped, in fact, there was space between all of them.
The findings have been published in the September 2, 2011, issue of the journal Science.