Scientists have defined neurons responsible for excessive food consumption at an unprecedented level of detail.
Two independent research teams have defined populations of neurons in the hypothalamus that are responsible for food-as-reward stimulation, but are likely not necessary to spur eating for survival. Both groups published their findings today (January 29) in Cell.
“These are big papers that start to define the complexity and heterogeneity of [the hypothalamus] and the specific sets of neurons that can produce dramatic behavioral results,” saidRalph DiLeone, a neurobiologist at Yale University who was not involved in the work.
Using optogenetics, neuroscientist Garret Stuber at the University of North Carolina, Chapel Hill, and his colleagues found that activating GABAergic neurons within the lateral hypothalamus (LH) led mice to feed more frequently, while inhibiting the activity of these neurons motivated the mice to not eat in excess. These neurons were distinct from other neuronal populations in the LH previously implicated in eating and other reward-related behaviors. When these neurons were genetically ablated, the mice were less motivated to obtain a liquid calorie reward. The scientists also visualized calcium signaling of hundreds of individual GABAergic neurons at once in free-moving mice by implanting microendoscopes into the LH and attaching a miniaturized fluorescence microscope to the animals’ heads. The calcium imaging showed distinct populations of GABAergic neurons active upon the first taste of a food reward or when the mice poked their noses—a sign of interest in the food—but rarely during both activities. Original Article »