You might’ve heard about the myth of the tongue taste map: the false idea that different parts of the tongue are responsible for perceiving different tastes (e.g., bitter in the back and sweet in the front).
But did you know that a similar so-called topographic map was thought to exist in the region of the brain responsible for taste perception, even after the tongue taste map was debunked?
This kind of topographical organization is common for various senses. For example, in the somatosensory cortex (where touch is perceived), your fingers and your back are represented in different areas. Similarly, in the auditory cortex, high and low frequencies are represented in different areas.
So when early imaging experiments suggested that the gustatory cortex is organized in the same way, no one was really surprised. After all, if it works for other senses, why wouldn’t it work for taste as well?
But a new study suggests otherwise. Using more advanced methods, the researchers showed that the gustatory cortex of mice has no topographic organization. Basically, there are no neatly defined areas in the brain for sweet or sour or bitter.
Instead, neurons responsible for different tastes are intermixed, forming a so-called “ensemble coding”. In other words, different patterns of activation of these neurons lead to the perception of different tastes, kind of how members of an orchestra can play different tunes together.
Why is this important? As mentioned before, topographic organization is an important principle underlying brain organization, so showing that taste doesn’t conform to this begs the question “why is it special?” and could lead to more exciting discoveries about taste perception.
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