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Maybe it starts with a low-energy feeling, or maybe you’re getting a little cranky. You might have a headache or difficulty concentrating. Your brain is sending you a message: You’re hungry. Find food.

Studies in mice have pinpointed a cluster of cells called AgRP neurons near the underside of the brain that may create this unpleasant hungry, even “hangry,” feeling. They sit near the brain’s blood supply, giving them access to hormones arriving from the stomach and fat tissue that indicate energy levels. When energy is low, they act on a variety of other brain areas to promote feeding.

By eavesdropping on AgRP neurons in mice, scientists have begun to untangle how these cells switch on and encourage animals to seek food when they’re low on nutrients, and how they sense food landing in the gut to turn back off. Researchers have also found that the activity of AgRP neurons goes awry in mice with symptoms akin to those of anorexia, and that activating these neurons can help to restore normal eating patterns in those animals.