Ask anyone who’s ever resolved to break up with sweets and then crumbled at the sight of a cookie: it’s tough to quit eating sugar. Now, a new animal study suggests that the reason why goes beyond the brain’s simple craving for sweetness. Sugar activates reward areas of the brain that are associated with both sweetness and the need for calories. (Regardless of your personal relationship with calories, your body considers them a big plus and goes after them.)
Now, in the new paper published in the journal Nature Neuroscience, researchers wanted to find out if these two rewards—sweetness and calories—travel along the same brain circuitry.
To find out, they fed mice a sugar solution with calories and a zero-calorie version made with sucralose, an artificial sweetener. They found that in the brains of the mice, sweet taste is processed in the ventral striatum (which is part of the brain’s reward system). But nutrition—including calories—was processed in another part of the reward center: the dorsal striatum, an evolutionarily ancient part of the brain that activates motor behavior.
“What we show now is that this supposedly motor part of the brain is not really completely motor, but it has a role in generating new behaviors that respond to rewards in the environment,” says senior author Ivan de Araujo, associate fellow at the Yale University-affiliated John B. Pierce Laboratory in New Haven. Read more