The hippocampus, which plays a role in decision-making, is sensitive to levels of hunger hormones produced in the gut.
- In mice, increased levels of the hunger hormone ghrelin reduced neuronal activity in the ventral hippocampus, a part of the brain that is used for decision-making.
- High levels of ghrelin promoted food intake in rodents.
- The researchers hope that these results could contribute to research into the mechanisms of eating disorders.
“Hunger is an internal state that not only stimulates appetite but also acts as a contextual cue for the control of eating-related behavior. The ventral hippocampus (the lower part of the hippocampus) is essential for differentiating between optimal behaviors depending on contexts, but it is not known how internal contexts, such as hunger, influence hippocampal circuits. wrote researchers from University College London (England) in a study published in the journal Neuron.
Brain: high ghrelin levels were associated with food intake
This is why they conducted an experiment on mice as part of the work. In detail, the scientists placed rodents in an arena containing food and observed how they acted when they were hungry or full, while analyzing their neuronal activity in real time using a scanner. The team focused on activity in the ventral hippocampus, a part of the brain that is used for decision-making, helping us form and use memories to guide our behavior.
According to the results, all mice spent time examining the food, but only hungry mice started eating. The authors found that the activity of a subset of brain cells in the ventral hippocampus increased when the animals approached food, and that this activity prevented the animal from eating. However, if the animals were hungry, neuronal activity in that area decreased and the hippocampus no longer stopped them from eating. The researchers observed that this corresponded to high levels of ghrelin, the hunger hormone, circulating in the blood.
Better understand how the “brain works” to prevent and treat EDs
“It appears that the seahorse curbs the animal’s feeding instinct when it encounters food, to ensure that the animal does not overeat,” said Dr Andrew MacAskill, co-lead author of the research, in a statement. “It is very important to be able to make decisions based on our hunger. If this goes wrong, it can lead to serious health problems. We hope that by improving our understanding of how the brain works, we can contribute to prevention and the treatment of eating disorders”, added Ryan Wee, who led the work.
Now, the researchers are continuing their study by examining whether hunger can impact learning or memory, testing whether mice perform non-food-specific tasks differently depending on their hunger levels. They say additional research could also help determine whether similar mechanisms are at play for stress or thirst.
