Brain areas controlling hunger identified

LOS ANGELES, Oct. 31 (UPI) -- U.S. scientists have identified the specific areas of the human brain that are responsible for feelings of hunger and fullness.

The University of California-Los Angeles researchers used the chemical leptin, which is produced by fat cells and has been known to inhibit hunger and promote feelings of being full.

Psychiatry Professor Edythe London, who led the study, used functional magnetic resonance imaging, or fMRI, to measure brain activity before and after leptin supplementation in brains of three adults. All three subjects had a genetic mutation causing leptin deficiency.

Researchers showed the adults images of food before and after leptin treatment, while taking fMRI images of their brains.

After receiving leptin, the subjects reported decreased feelings of hunger -- and researchers observed decreased activity in certain brain regions associated with hunger. At the same time, the scientists observed increased brain activity in the prefrontal cortex -- an area of the brain previously associated with feeling full or satisfied.

London said the study results might help identify new targets for the treatment of obesity and related metabolic disorders.

The research appears in the online early edition of the Proceedings of the National Academy of Science.