UPTON, NY -- Researchers at the U.S. Department of Energy's Brookhaven National Laboratory have found new clues to how the brain and the stomach interact with emotions to cause overeating and obesity. By looking at how the human brain responds to "fullness" messages sent to the brain by an implanted device that stimulates the stomach, the scientists have identified brain circuits that motivate the desire to overeat in the obese -- the same circuits that cause addicted individuals to crave drugs. The scientists have also verified that these circuits play a critical role in eating behaviors linked to soothing negative emotions. The study appears in the October 17, 2006 issue of the Proceedings of the National Academy of Sciences, published online in PNAS Early Edition the week of October 2.
"This study opens new territory in understanding how the body and brain connect to each other, and how this connection is tied to obesity," said lead author Gene-Jack Wang of Brookhaven Lab's Center for Translational Neuroimaging. "We were able to simulate the process that takes place when the stomach is full, and for the first time we could see the pathway from the stomach to the brain that turns 'off' the brain's desire to continue eating."
Wang and colleagues studied the brain metabolism of seven obese individuals who had gastric stimulators implanted for one to two years. The stimulator, an investigational device much like a pacemaker, provides low levels of electrical stimulation to the vagus nerve, causing the stomach to expand and produce peptides that send messages of "fullness" to the brain. The device has been shown to reduce the desire to eat. This study provides the first direct evidence of which brain regions are involved in this response and gives new clues to how satiety signals sent by the stomach affect eating behavior.
Participants in the study received two separate positron emission tomography (PET) brain scans two weeks apart: on
Contact: Mona S. Rowe
DOE/Brookhaven National Laboratory