Activating neurons in an area of the brain not previously associated with feeding can produce binge-eating behavior in mice, according to a new study from Yale researchers.
When activated by light probes, GABA neurons in an understudied area of the brain called the zona incerta induce mice to return repeatedly to feed, Anthony van den Pol and Xiaobing Zhang of the Department of Neurosurgery report.
“What was most remarkable was the rapidity with which the mice began to eat. Although many brain regions contribute to the regulation of energy balance and food intake, I am not aware of any other part of the brain that can be stimulated to generate feeding within two to three seconds,”
said van den Pol.
Zona Incerta Neurons
Mice gained considerable body weight if their zona incerta was stimulated with optogenetics, but then returned to normal weight in the absence of stimulation.
“The parallel with human binge-eating is interesting,” van den Pol said. “The mice prefer the animal equivalent of potato chips, candy, or cake.”
The mice seemed to enjoy the stimulation, staying in the part of the chamber where zona incerta neurons had been activated even when researchers were not actively stimulating the region.
Specifically, optogenetic stimulation of mouse zona incerta (ZI) γ-aminobutyric acid (GABA) neurons or their axonal projections to paraventricular thalamus (PVT) excitatory neurons immediately (in 2 to 3 seconds) evoked binge-like eating.
Research has primarily focused on the medial and lateral hypothalamus as centers for feeding behavior and largely ignored the nearby zona incerta. However, some patients who undergo deep brain stimulation for treatment of movement disorders show increased interest in eating, perhaps due to stimulation of nearby zone incerta, van den Pol noted.
Image: Bd008, CC BY-SA 4.0. Cages for rat equiped with optogenetic LED commutators.