Taste is all in your head

Tweaking mouse brain cells turns water bitter or sweet

mouse reacting to bitter water

SENSORY DELUSION  By creating a bitter perception by tweaking nerve cell behavior in this mouse, scientists show that taste perception lies in the brain.

Y. Peng et al/Nature 2015

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It’s not water into wine, but close enough. By stimulating certain nerve cells in the brains of mice, scientists made plain water taste sweet or bitter. The results show that the brain — not the tongue — is the ultimate tastemaker.

Columbia University neuroscientist Charles Zuker and colleagues took aim at a part of the mouse brain called the gustatory cortex. There, the nerve cells responsible for sensing bitter lie about two millimeters from those that sense sweet. Researchers tweaked these groups of cells so they would spring into action when light hit them.

When the sweet-sensing nerve cells were stimulated with a laser, mice eagerly lapped up plain water, even though the mice were plenty hydrated. And when the bitter-sensing cells were stimulated, the mice would take a lick of that same plain water and then grimace, occasionally gagging and trying to wipe the fictional “taste” out of their mouths. The results show that these nerve cells can manufacture a taste, even when none exists. 

FAKE OUT By stimulating certain nerve cells, scientists made plain water taste bitter to this mouse. Y. Peng et al/Nature 2015

Laura Sanders is the neuroscience writer. She holds a Ph.D. in molecular biology from the University of Southern California.

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