By Bahar Gholipour, Staff Writer
Published: 09/26/2013 04:19 PM EDT on LiveScience
When a particular circuit in the brain is stimulated, it causes mice to voraciously gorge on food even though they are well fed, and deactivating this circuit keeps starving mice from eating, a new study shows.
The findings suggest that a breakdown within this neural network could contribute to unhealthy eating behaviors, the researchers said, although more work is needed to see whether the findings are also true of people.
The circuit lies in a brain area called the "bed nucleus of the stria terminalis" (BNST), and affects eating by inhibiting activity in another region, called the lateral hypothalamus, which is known to control eating, according to the study, published today (Sept. 26) in the journal Science.
"Normally, there's a population of neurons in the lateral hypothalamus that's putting the brakes on eating," said study researcher Garret Stuber, a neuroscientist at the University of North Carolina at Chapel Hill. "But when you shut those cells down by stimulating this pathway, that releases the brake, and the animal starts to eat."
The lateral hypothalamus has been known for more than 50 years to be an important part of the brain for controlling eating. Scientists had learned that putting stimulating electrodes in the lateral hypothalamus of animals would influence their eating behavior, but exactly how it works has been a mystery.
"Nobody had a good mechanistic explanation for what's actually being stimulated or activated within this brain structure," Stuber said.
In the new study, the researchers focused on examining how the BNST influences activity in the lateral hypothalamus.
To manipulate the BNST neurons, the researchers used a technique called optogenetics that allowed them to activate specific neurons using light. They found that, upon activation, BNST neurons suppressed activity in the lateral hypothalamus, and caused the well-fed mice to immediately start eating.
"When we stimulate the pathway, the animals eat a third to 50 percent of the calories they eat in a normal day, in about 20 minutes," Stuber said. For a person, that would probably be the equivalent of eating lunch and dinner in one sitting, he said. [7 Foods You Can Overdose On]
What's more, the researchers gave the animals a choice in some of the experiments between regular food and a tasty food with a high fat content, analogous to junk food. They found that when they activated the circuit, the animals showed a strong preference for the junk food.
Conversely, deactivating the circuit caused the animals to immediately stop eating, even if their stomachs were empty.
The BNST is thought to be a hub that integrates emotionally relevant information coming from several parts of the brain. Although the experiments didn't aim to study the link between emotional states and feeding behavior, the findings may explain how emotions can influence eating, Stuber said.
"BNST is really important for affective behavior state in response to emotionally relevant stimuli, and the results show the output of those cells can actually directly modulate feeding behavior," he said.
Identifying a neural circuit that controls feeding, and understanding how the cells in this circuit work, could lead to future treatments for such conditions as obesity, the researchers said.
"Now that we know this is a critical circuit for feeding, we can start looking at this in humans," Stuber said.
Email Bahar Gholipour or follow her @alterwired. Follow LiveScience @livescience, Facebook & Google+. Original article on LiveScience.
Copyright 2013 LiveScience, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed. ]]>
Our 2024 Coverage Needs You
It's Another Trump-Biden Showdown — And We Need Your Help
The Future Of Democracy Is At Stake
Our 2024 Coverage Needs You
Your Loyalty Means The World To Us
As Americans head to the polls in 2024, the very future of our country is at stake. At HuffPost, we believe that a free press is critical to creating well-informed voters. That's why our journalism is free for everyone, even though other newsrooms retreat behind expensive paywalls.
Our journalists will continue to cover the twists and turns during this historic presidential election. With your help, we'll bring you hard-hitting investigations, well-researched analysis and timely takes you can't find elsewhere. Reporting in this current political climate is a responsibility we do not take lightly, and we thank you for your support.
Contribute as little as $2 to keep our news free for all.
Can't afford to donate? Support HuffPost by creating a free account and log in while you read.
The 2024 election is heating up, and women's rights, health care, voting rights, and the very future of democracy are all at stake. Donald Trump will face Joe Biden in the most consequential vote of our time. And HuffPost will be there, covering every twist and turn. America's future hangs in the balance. Would you consider contributing to support our journalism and keep it free for all during this critical season?
HuffPost believes news should be accessible to everyone, regardless of their ability to pay for it. We rely on readers like you to help fund our work. Any contribution you can make — even as little as $2 — goes directly toward supporting the impactful journalism that we will continue to produce this year. Thank you for being part of our story.
Can't afford to donate? Support HuffPost by creating a free account and log in while you read.
It's official: Donald Trump will face Joe Biden this fall in the presidential election. As we face the most consequential presidential election of our time, HuffPost is committed to bringing you up-to-date, accurate news about the 2024 race. While other outlets have retreated behind paywalls, you can trust our news will stay free.
But we can't do it without your help. Reader funding is one of the key ways we support our newsroom. Would you consider making a donation to help fund our news during this critical time? Your contributions are vital to supporting a free press.
Contribute as little as $2 to keep our journalism free and accessible to all.
Can't afford to donate? Support HuffPost by creating a free account and log in while you read.
As Americans head to the polls in 2024, the very future of our country is at stake. At HuffPost, we believe that a free press is critical to creating well-informed voters. That's why our journalism is free for everyone, even though other newsrooms retreat behind expensive paywalls.
Our journalists will continue to cover the twists and turns during this historic presidential election. With your help, we'll bring you hard-hitting investigations, well-researched analysis and timely takes you can't find elsewhere. Reporting in this current political climate is a responsibility we do not take lightly, and we thank you for your support.
Contribute as little as $2 to keep our news free for all.
Can't afford to donate? Support HuffPost by creating a free account and log in while you read.
Dear HuffPost Reader
Thank you for your past contribution to HuffPost. We are sincerely grateful for readers like you who help us ensure that we can keep our journalism free for everyone.
The stakes are high this year, and our 2024 coverage could use continued support. Would you consider becoming a regular HuffPost contributor?
Dear HuffPost Reader
Thank you for your past contribution to HuffPost. We are sincerely grateful for readers like you who help us ensure that we can keep our journalism free for everyone.
The stakes are high this year, and our 2024 coverage could use continued support. If circumstances have changed since you last contributed, we hope you'll consider contributing to HuffPost once more.
Support HuffPostAlready contributed? Log in to hide these messages.