Brain mechanisms of sweetness and palatability of sugars.

Sugars are sweet and palatable. Sweetness is detected by the neural system, whereas palatability may be detected within the neural and chemical systems in the brain. Sweetness is discriminated from other tastes by different receptor sites on taste bud cells, a different subset of fibers in the taste nerves, and different projection zones in the brain. The benzodiazepine and opioid systems are related to palatability, and the dopaminergic system mediates the motivation to consume palatable food.