Scientists studying mouse brains have found a way to disrupt the message relayed between different parts of the brain when sugar is ingested. When sugar touches the tongue, the nervous system relays a message to the amygdala that conflates sweetness with pleasure, writes Peter Hess for Inverse. In their study, researchers from Columbia University disrupted the amygdala—responsible for the pleasant or unpleasant experience linked to taste—and found that the mice still detected bitter and sweet flavors, but didn’t show a preference for one or a distaste for the other.
The research alters the way the mouse brain’s taste center, called the “gustatory cortex,” communicates with the amygdala. When the research team activated the neurons associated with sweetness, the mice reacted to a neutral stimulus like plain water as if it was sweet. The opposite was observed when the neurons associated with bitterness were activated—the mice drinking water responded as if it was bitter. The researchers described their findings in the journal Nature explaining that this switch has the potential reverse the mice’s emotional reactions to sweet or bitter tastes.
In another experiment, the team silenced the neurons in the amygdala that determine how pleasurable a taste is. They found that these mice, although able to identify sweet and bitter, had no appetite for sweetness, showing that the pleasure-making process was entirely disrupted. From this study, the team hopes to gain insight into eating disorders that result from exaggerated responses to food.
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