Unraveling the Mystery of Why We Eat Too Much

DOI:10.1016 / j.neuron.2021.09.020

Commentary

In 2019, researchers at the Stuber Lab at the University of Washington School of Medicine found that certain cells light up in obese mice and interfere with signals that indicate satiety or feeling full.

The study delves deeper into the role of these cells.

They found that these cells are located in the brain's lateral hypothalamic area, the hub that regulates motivated behavior, including eating, and that these neurons communicate with two different brain regions.

This is the ventral tegmental area, which is best known for playing a major role in motivation, reward and addiction. 

The Stuber Lab is studying the function of key cell groups in the brain's reward circuitry and characterizing their role in addiction and mental illness in order to discover treatments.

One question is whether these cells can be targeted by drugs without harming other parts of the brain.

The researchers found that neurons in the lateral habenula were more responsive than neurons in the ventral tegmental area when the mice were fed, suggesting that these neurons may play a major role in food induction.

They also looked at the effects of the hormones leptin and ghrelin on the way we eat, both of which are thought to regulate behavior through their effects on the mesolimbic dopamine system, an important component of the reward pathway in the brain.

However, since it is unclear how these hormones affect neurons in the brain's lateral hypothalamic area, the researchers found that leptin slows down the activity of neurons projecting to the lateral habenula and increases the activity of neurons projecting to the ventral tegmental area.

However, they showed that the brain circuits that control eating overlap, at least partially, with those involved in drug addiction.