Research locates brain region responsible for feeling full

New research at the University of Arizona has located the region of the brain and neural networks that control when people feel full after eating. Researchers are hoping that this discovery will allow more targeted drugs to control hunger, with fewer side effects. AZ PBS talked to the lead author of this study, Haijiang Cai of the University of Arizona Department of Neuroscience.

“Obviously, feeling that you’ve eaten enough food and stop eating is critical to our survival. Once we feel satiated, we need to stop eating or else we’ll explode,” Cai said.

“We’ve known that it’s mediated by a bunch of brain regions, but it’s never been completely understood,” Cai said. “So far what we know is that our body, our gut, will secrete a hormone called cholecystokinin or CCK, which tells our brain that you’ve had enough food so you stop eating.”

Previous research had mapped the circuit for satiation to the amygdala, a region of the brain responsible for fear and other strong emotions. By combining this information with the fact that the brain region responsible would be affected by CCK, they were able to trace it to a poorly-understood part of the brain.

“We found a new brain region called the parasubthalamic nucleus, or PSTh. The neurons in this region are much more specific than the central amygdala, and they are directly affected by satiating hormones like CCK, and directly suppressing these neurons will suppress eating,” Cai said.

The location of this region is important, as it may help explain why eating is so closely tied to emotions.

“We know that eating behavior is tied to emotion. For example, if we have a good meal we feel happy, some people when they are stressed eat less, others eat more. Patients who have an eating disorder or obesity also have emotional problems like depression or anxiety,” Cai said. “So, identifying the circuit between the amygdala and PSTh will help us understand how the neural circuits that control eating and the neural circuits that control emotion talk to each other.”

Cai said he hopes that this will lead to the development of more specific treatments for eating disorders, which will allow them to be addressed directly, without side effects.