Organisms must feed in order to meet their nutritional requirements. In humans, dysfunctional feeding behavior can take the form of destructive eating disorders including anorexia, bulimia, overeating and addiction. Feeding behavior comprises discrete elements that include motivation (or hunger) and consumption. Understanding the neurological pathways that underlie these elements could provide mechanistic insight into the causes of eating disorders, but identifying the neural processes associated with hunger and consumption has proven challenging. As global research initiatives have encouraged the development of new technologies to study the brain, advanced biological imaging techniques have become more widely available. Scientists led by Garret Stuber (University of North Carolina at Chapel Hill) recently applied innovative bioimaging technology to identify specific neurons that are activated in the brains of mice in conjunction with hunger and with consumption. The discovery adds to our knowledge about the brain's involvement in feeding behavior and might lead to more effective treatment strategies for eating disorders. The findings were presented at Neuroscience 2014, the annual meeting of the Society for Neuroscience (15–19 November 2014; Washington, DC).

“The area of the brain we focused on—the lateral hypothalamus—is known to be involved in elements of eating, including hunger and consumption. Until now, however, we didn't know which particular cells within that area of the brain contribute to each of those behaviors,” said Stuber in a press release.

To identify the neurons associated with hunger and consumption, Stuber and his colleagues used tiny visual probes called microendoscopes implanted directly into the lateral hypothalamus in mice. The microendoscopes were coupled with miniature, very-high-resolution fluorescence microscopes, enabling the researchers to observe individual neurons labeled with fluorescent proteins. The mice were given several behavioral tests in which they had to expend effort to obtain food, and their neural activity patterns were recorded. The researchers then looked for changes in neural activity patterns that correlated with behavioral demands.

Stuber's group discovered that specific groups of neurons in the lateral hypothalamus became activated when the mice were working to gain access to food (reflecting the motivation or hunger element of feeding behavior). Different neurons were activated during food consumption. The findings suggest that dysfunction or alteration of specific neurons in the lateral hypothalamus might contribute to the development of eating disorders and that regulating the activity of those neurons might form the basis for new ways of treating them.