Brain circuitry and sugar

If you’re someone who eats a lot of sugary things – you’ll know how difficult it is to quit the habit. A new study has shed some light on why this is the case.

Here are some points from a recent article on the study:

• Sugar activates reward areas of the brain that are associated with both sweetness and the need for calories.
• 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 centre: the dorsal striatum, an evolutionarily ancient part of the brain that activates motor behaviour.
• What they found is that this supposedly motor part of the brain is not really completely motor, but it has a role in generating new behaviours that respond to rewards in the environment.
• Surprisingly, the mice brain’s desire for calories even overrode the desire for sweetness. In fact, when the researchers laced the sugary drink with a bitter, terrible-tasting compound, the mice licked more of it than the sweet-tasting calorie-free kind.
• To confirm the results, they repeated the experiment, but first, they removed cells in the dorsal striatum of the mice. Absent the brain region that prioritises calories, the mice chose the sweet-tasting sucralose drink, not the high-calorie but awful-tasting one.

Follow the link to read the full article.