A structure in our brain, the ventral pallidum, manages our emotions and food preferences. This structure, which follows the same circuit as that associated with addiction, can be changed artificially to modify our tastes.
- The ventral pallidum, a brain structure dedicated to emotions, also controls our food preferences.
- Depending on our mood and our level of dehydration, our brain will be more or less influenced by food.
- It is possible to change our food preferences artificially, because they work on the same principle as an addiction.
What predestines our taste for one food rather than another? Some would say appetizing flavors or textures. But researchers at Johns Hopkins University (USA) would rather rely on our emotions and our level of dehydration. In their work published by the journal Science Advances on November 4, 2020, they succeeded in determining the role of the ventral pallidum in what we like to eat.
Mood and thirst, the two drivers of our food cravings
The scientists based their research on a discovery they made two years ago that neuronal activity in the ventral pallidum, the part responsible for managing emotions, is linked to our food preferences.
By analyzing mice, the researchers demonstrated that this region of the brain updates our food preferences over time. Moreover, these conditions change depending on our mood and our level of thirst. This is why certain foods are Proust’s madeleines, because they evoke an emotion or a memory attached to a specific food.
“We knew that the ventral pallidum is involved in this processrecalls Patricia Janak, lead author of the study and professor of psychology and neuroscience at Johns Hopkins University. Exactly how neurons do this was still a bit of a mystery, especially in real time, when the best decision to make now can change depending on your state.”
By manipulating this region in mice, the researchers were able to influence their food preferences, especially with regard to rewards. For this, they gave two options to mice that they had previously made thirsty. By activating a first lever, they obtain plain water while the second lever delivers them sugar water.
Artificially changed preferences
“At first they chose plain water when they were thirstysays David Ottenheimer, a former doctoral student at John Hopkins, who has since moved to the University of Washington. At the end of the test, when they were no longer thirsty, they chose sugar water, which tastes sweeter.” At the same time, the team monitored the mice’s brain activity. They discovered that their neurons reflected the rodents’ choices at each reward. As the mice consumed sugar water, neural activity in favor of the water decreased, surely in proportion to the urge to quench their thirst.
Knowing that sugar has a strong addictive power and that this could falsify the first experience, they repeated the same test, this time with sugar water in the face of a less desirable flavor for the taste buds. By artificially manipulating the neurons responsible for the ventral pallidum, they succeeded in diverting the mice from the sugar water.
“We hypothesize that neurons in the ventral pallidum that track our preferences may in fact be involved in shaping the choices we make when faced with food decisions.”, explains David Ottenheimer. His colleague Patricia Janak continues his thought: “These same circuits are responsible for the choices made in matters of addiction. So, the insights we gain here can help us understand how we prioritize certain drugs over other rewards.”
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