Researchers in the US have turned taste on and off in mice simply by activating and silencing certain brain cells. This demonstrates for the first time that taste is hardwired in the brain, and not dictated by our tastebuds, flipping our previous understanding of how taste works on its head.
It was previously thought that the taste receptors on our tongue perceived the five basic tastes – sweet, salty, sour, bitter, and umami – and then passed these messages onto our brain, where it registered what we’d just tasted. But the new study shows that although our tongues do detect the presence of certain chemicals, it’s our brains that perceive flavour.
Previous work by Zuker’s lab discovered that our tongue has dedicated receptors for each taste, and that each class of receptors sends a specific signal to the brain. More recently, the team built on this by showing that in addition to dedicated receptors, there are unique sets of brain cells – each in different locations – that receive these signals. The red area below is the bitter neurons, and the aqua shows where the sweet brain cells are.