Scientists from
Columbia University have figured out how to turn tastes on and off in the brain
using optogenetics, a technique that uses penetrating light and genetic
manipulation to turn brain cells on and off. They reported their findings in an
article published last week in Nature. By manipulating brain cells in mice this
way, the scientists were able to evoke different tastes without the food
chemicals actually being present on the mice’s tongues. The experiments re-conceptualize
what we consider the sensory experience.
Results further
demonstrate that the sense of taste is hardwired in our brains unlike our sense
of smell, which is strongly linked to taste but almost entirely dependent on
experience. Typically when we eat, the raised bumps, or papillae, that cover
our tongues, pick up chemicals in foods and transmit tastes to the brain. There
are five main types of papillae corresponding to each of the five basic
tastes—sweet, sour, salty, bitter and umami. Contrary to popular belief, these
aren’t clustered in particular places on the tongue, with bitter in the back
and sweet at the front, but are spaced about evenly on the tongue.
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