Overeating disorders are increasingly common - it's one of the many reasons the world is facing an obesity epidemic. So a team of neuroscientists in the US wanted to find out which part of the brain causes overeating and try to switch it off.

First, the scientists genetically modified some mice so that a small group of their brain cells would respond to light in different ways. Crucially, they picked cells that send messages to the part of the brain that affects the pitta patterns of tiny feet. Then, when they shone a laser into the mouse's brain, they were able to either activate those neurons or make them go quiet.

The results were astounding. In the first set of mice (the ones that had been modified so that the laser would make the neurons so quiet) when the light was switched on, they would not eat. Even when they got hungry.

In the second set of mice (whose brains had been programmed to do the reverse) when the laser was switched on, they would start eating and they didn't stop eating until the light was switched off. Even when they were full.

You can watch the results for yourself in this video:

The tests only lasted for 20 minutes at a time, so the researchers aren't sure if over a longer period, there would be lasting changes. Would the mice overeat to the point of sickness or starve themselves?

The scientists hope that their research has helped to uncover the pathways in the brain that regulate human as well as mouse feeding patterns - which could help to better treat eating disorders including anorexia and overeating. Speaking to ScienceNews, Garret Stuber, one of the lead researchers said "We think of feeding in terms of metabolism and body stuff, but at the end of the day, it's controlled by the brain."

Rejargonator

The paper, originally published in the journal Science, was titled "The Inhibitory Circuit Architecture of the Lateral Hypothalamus Orchestrates Feeding". Here are the bits we've simplified:

Optogenetics: the laser technique that was used

Murinae: scientific word for mouse

preferentially innervate: to stimulate nerves into doing something

lateral hypothalamus: part of the hypothalamus which takes care of certain metabolic processes - it's just above the brain stem and is about the size of an almond

BNST: aka the bed nucleus of the stria terminalis - the part of the brain where those on-off neurons were found

Do you think this research will ultimately lead to fewer humans overeating? Would you use the new science if it did? Tell us what you think

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