The researchers found that food stimulation significantly increased whole brain metabolism. Metabolism was higher in all regions of the brain examined, except for the occipital cortex, which controls vision and would not be affected. The areas most affected were the superior temporal, anterior insula, and orbitofrontal cortices. Food stimulation also resulted in increases in self-reports of hunger and desire for food. Increases in metabolism in the right orbitofrontal cortex were the ones that were most significantly correlated with increased reports of hunger.

This figure shows the areas of the brain that "lit up" with higher metabolism during food stimulation in the study. The colored areas are from a statistical parametric mapping (SPM) analysis of PET scans of all subjects in both the food stimulation and neutral intervention conditions of the study. These images are superimposed on MR images from one person's brain (taken from above), which are used to demonstrate correct anatomical positioning. All "lit" areas represent significant differences in metabolism between the two study conditions: white represents higher metabolism while red represents lower metabolism.

Most intriguing is that the orbitofrontal cortex (see arrows in the two lower left brain images labeled "OF") has higher metabolism. Studies at Brookhaven and elsewhere have shown that this brain region, which houses the dopamine system, is also active in addiction, reward and motivation.

This study was funded by the Office of Biological and Environmental Research within the U.S. Department of Energy ™s Office of Science and the National Institute on Drug Abuse (NIDA). Scientists from NIDA, Stony Brook University, and St. Luke ™s/Roosevelt Hospital in New York City contributed to the study.