Gulping vs Drinking: Where Can We Find Reward?

Dopamine, a word that might pop up whenever you think of pleasure and reward pathways. However, it’s broad influence has an irresistible lure for neuroscientists to research. Last year, and article was published by the New York Times titled” Why Gulping Down  A Cold Drink Feels So Rewarding”. In this article, Veronique Greenwood summarizes a study done by a group of scientists who have researched how thirst stimuli function in mammals claim that the feeling of reward based neural systems work independently of those involved in regulating water intake. The gulping motion made by the throat as liquid passes sends a message to the brain that water has been consumed has been found to decrease neuron activity responsible to remind the body to stay hydrated.

While research related to consumption and reward neurons, like the extensive work of Ted M. Hsu, has been done, findings suggest a considerable overlap between homeostatic and reward-related neural processes. Although both research find this relationship, researchers in the New York Times article study found that this decrease in neuronal activity is reduced no matter if the substance swallowed/ gulped has an effect in keeping us hydrated. These results suggest that our brains can be tricked into feeling rewarded when thirsty by the sole act of gulping even if there is no hydration. On a side note, is this the reason behind the common advice when someone is on a diet to chew slowly and swallow food in small portions so they can feel full with a smaller meal? Nevertheless, the body will eventually feel that there is no presence of water arriving and thirst will rise up again. With this idea in mind, scientists ran various experiments with different groups where one group mice were injected water directly to their stomach, the second group had artificially manipulated thirst neurons to feel the sensation of satiation, and a the third, the control, group drank water normally. 

Surprisingly, results showed that the second and third groups of mice showed a neuronal pathway that released of dopamine, creating the sensation of reward and satiation. Nonetheless, the first group, the group that did not have a gulping sensation due to the lack of swallowing, did not have a release of dopamine, therefore there was no reward or pleasure met. As this study concludes, we can infer that the act of hydration is not rewarding rather gulping the water is what produces a feeling reward.