See Food, Eat Food, New Study Finds
May 12, 2004
Charleston Daily Mail

Everyone knows that seeing food can trigger the innate drive to eat, and now scientists at Brookhaven National Laboratory have identified the brain network involved in this process - and hope the finding can ultimately explain why so many people overeat.

Dr. Gene-Jack Wang and his colleagues at the Upton, N.Y., laboratory brought 12 hungry, average-sized adults into the lab and showed them 10 favorite foods one at a time over a two-day testing period.

The volunteers could see, smell and talk about the food in front of them, but no eating was allowed. (They hadn't eaten for at least 17 hours.) A cotton swab introduced the taste of the food onto their tongues.

Minutes later, they were hooked to a brain scan. The areas of the brain activated are those that regulate drive and motivation, suggesting that stimulating these brain regions drives a person to seek (and consume) food.

All said they were hungrier after seeing their favorite foods, which was confirmed by the brain activity in the scans.

The study was published in the journal Neuroimage.

According to Wang, the area that controls taste, which sits close to the ear in the brain's somatosensory cortex, became active, as well as the anterior insula, an area behind the eye thought to control appetite. The scientists were most excited by activation in the orbitofrontal cortex, in the front of the brain. This area is rich in dopamine and regulates pleasurable behavior, such as eating.

Wang suspects people who overeat may have an altered, perhaps exaggerated, response in these regions. The scientists previously discovered that obese people have about 14 percent fewer receptors for the chemical dopamine in the striatum, which regulates pleasure and reward. They believe this reduction in chemical receptors may trigger overeating to stimulate "reward and motivation" circuits.