Compulsive overeating isn’t your fault after all

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Fighting hard to put down that pack of chips or chocolate? Blame it all on a pathway in your brain! Compulsive overeating and sugar addiction are major threats to human health. Potential treatments involve manipulating the normal ‘feeding’ behaviour or neural circuit associated with it, which is quite risky.  A study published January 29th in the journal Cell led by neuroscientist Garret Stuber revealed a reward-related neural circuit that specifically controls compulsive sugar consumption in mice. However this circuit doesn’t prevent ‘feeding’ that is necessary for survival, providing a novel target for the safe and effective treatment of compulsive overeating in humans.

This group of researchers from South Carolina based their studies on a 60 year old observation. According to this study, it was found that scientists could electrically stimulate brain cells in the region of a mouse’s brain – called the lateral hypothalamus (LH) – causing the mouse to eat even when it was not hungry. The neurons of the LH are diverse, and known to be involved in reward-related behaviors such as eating, drinking, and sex. Stuber wanted to focus specifically on one type of neurons – namely the GABA neurons (neurons that produce GABA as their output).

His group made use of a powerful technique called Optogenetics, which uses light to modulate neurons that are made light sensitive. In this case, genetically engineered algal proteins were utilized to impart light sensitivity and these neurons were stimulated specifically with the help of fibre optic cables. They found that activation of GABA neurons within LH caused frequent feeding behavior. On the other hand, the mice were motivated to not eat in excess when the activity of these neurons was inhibited. When a group of mice was allowed to freely explore an area with food or made to work to obtain a sweet reward, fascinating observations were made. Upon imaging the activity of the LH neurons, they uncovered distinct subsets of neurons that either mediate food-seeking behavior or respond to reward consumption.

“The study underscores that obesity and other eating disorders have a neurological basis,” says Stuber. “With further study, we should be able to figure out how to regulate the activity of cells in a specific region of the brain and develop treatments.” Cynthia Bulik, Distinguished Professor of eating disorders at UNC’s School of Medicine and the Gillings School of Global Public Health, said, “Stuber’s work drills down to the precise biological mechanisms that drive binge eating and will lead us away from stigmatizing explanations that invoke blame and a lack of willpower.”

What makes this study so significant is that it starts to define complexity and heterogeneity of [the hypothalamus] and the specific sets of neurons that can produce dramatic behavioural results. It also makes smart use of an existing set of highly innovative and sensitive techniques. Furthermore, this discovery could provide insights into the cause of obesity, as well as lead to treatments for anorexia, bulimia and binge eating.

The original article can be accessed here.

Disclaimer: This articles does not reflect any personal views of the authors/editors

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