Brian Connections Tied to Overeating Pinpointed in Lab Mice

Researchers have pinpointed the precise cellular connections responsible for triggering overeating, a find that could lead to treatments for prevalent eating disorders in the United States.

"The study underscores that obesity and other eating disorders have a neurological basis," said senior study author Garret Stuber assistant professor in the department of psychiatry and department of cell biology and physiology a t the University of North Carolina School of Medicine. "With further study, we could figure out how to regulate the activity of cells in a specific region of the brain and develop treatments."

The find could change the national conversation about binge eating and other eating disorders, leading away from stigmatizing explanations that evoke blame and lack of will power, said Cynthia Bulik, an eating disorder expert not involved in the study.

Stuber and his team used lab mice to focus on one cell type --- gaba neurons in the bed nucleus of the stria terminalis, or BNST.

"The BNST is an outcropping of the amygdala, the part of the brain associated with emotion. The BNST also forms a bridge between the amygdala and the lateral hypothalamus, the brain region that drives primal functions such as eating, sexual behavior, and aggression," the according to a UNC School of Medicine Statement.

The team implanted fiber optic cables in the brains of mice that had been genetically altered to become sensitive to light. Brain tissue is usually not sensitive to light. This allowed the researchers to shine light through the cables and onto BNST synapses to provoke responses.

The mice, which has been intentionally well-fed, began to eat voraciously and with a strong preference towards high-fat foods as soon as the light hit the BNST synapses.

"They would essentially eat up to half their daily caloric intake in about 20 minutes," Stuber said. "This suggests that this BNST pathway could play a role in food consumption and pathological conditions such as binge eating."

Stimulating the BNST also led the mice to exhibit behaviors associated with reward, the reserachers reported, a find that suggests that shining light on BNST cells enhanced the pleasure of eating. Conversely, shutting down the BNST pathway resulted in the mice to showing little interest in eating, even if they had been deprived of food.

"We were able to really home in on the precise neural circuit connection that was causing this phenomenon that's been observed for more than 50 years," Stuber said.

The research is published in the journal Science.