Scientists find a cerebral signal that could help us judge the holiday buffet

At holiday buffets and potlucks, people quickly calculate the dishes to try and the quantities to take. Neuroscientists at Johns Hopkins University have discovered a region of the brain that seems to be closely linked to such decisions about food preferences.
Researchers working with rats have discovered robust neuronal activity related to the choice of foods in a previously neglected part of the brain. The discovery suggests that this region of the brain could be the key to developing therapies and treatments to encourage healthy eating. The results should be published in Nature Communications.
"We have found a region of the brain that reflects our perception of food in an extremely dominant way," said lead author David Ottenheimer, a graduate student in neuroscience at Johns Hopkins University. "The level of brain activity we saw exceeded our expectations by far."
The research team wanted to know how the brain determines what and how much to eat when you have several good food choices. This is a situation that people are confronted with daily, if not at buffets or meals in common, and then when they are looking at restaurant menus or what's in the fridge.
This may seem automatic as you move through a buffet, but when thinking of a cheese macaroni or mashed potatoes, the brain must quickly determine which of these choices are quite similar – tasty, treats, carbs – would be the most rewarding. According to Ottenheimer, although we can have both, the favorite dish will probably be consumed faster and with larger bites.
To investigate this issue, the researchers offered rats two similar sugary drinks. The rats preferred the one made with sucrose to the one containing maltodextrin, and when they received sucrose they licked it faster.
Over several days, the rats received one or the other glbad. During this time, the team mapped the brain activity of the rats just when the animals understood what drink they had drunk, identifying the neurons that recorded the excitement for sucrose and the disappointment for maltodextrin.
The activated neurons were in an area called the ventral pallidum, a zone long badociated with the perception of reward and pleasure, but considered rather a secondary role.
Then, the team presented the rats with a set of different options: the maltodextrin drink or the pure water. In this scenario, when the rats received maltodextrin, the ventral pallidum neurons were fired as if they had sucrose. This suggests that the brain area makes context-dependent decisions, targeting the best food option at all times.
"Because neural signaling of the ventral pallidum changes immediately when the rat changes its preferred flavor ranking, we view this response as a real-time reading of what you prefer among currently available options," said Patricia Janak, principal author. , Bloomberg Distinguished Professor of Psychological and Cerebral Sciences and Neuroscience.
The next step is to understand what signage means in this part of the brain. Is it used to reinforce previous foraging actions and make them more likely to reproduce? Or is it used to inform future decisions and refer them to a food reward over the next time a food choice will be presented to someone?
"Our data suggest that further study of the ventral pallidum will be essential to understanding how we make food decisions," Ottenheimer said. "If we want to understand why one food can be exciting in one scenario and disappointing in another, the ventral pallidum could be the key." ###
The research team also included Jocelyn M. Richard, a former Johns Hopkins Postdoctoral Fellow in Psychological and Cerebral Sciences, who is now an Assistant Professor at the University of Minnesota.
This work was funded by National Institutes of Health grants, 5T32NS91018-17, K99AA025384, R01DA035943; a NARSAD fellowship for young researchers; and the National Science Foundation Postgraduate Fellowship.

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