July 7, 2000
Volume XXXIII, No. 27

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Imaging study sheds light on brain's response to food

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There's more to feeling full than having a knot in one's stomach. In fact, specific parts of the brain are activated so that you feel ready to push away from the table, say researchers at the Health Science Center and University of Florida (UF). Their latest findings with ramifications for future studies of obesity, diabetes and eating disorders are reported in the June 29 issue of the international journal Nature.

The scientists, from UTHSC's Research Imaging Center and Department of Physiology and UF's Department of Psychiatry and Brain Institute, developed a new mathematical model for plotting the brain's response to food. In a letter to Nature, they describe a study of 21 participants who drank orange-flavored sugar water while undergoing functional magnetic resonance imaging (functional MRI). Images were recorded for 10 minutes before consumption of the glucose and for 38 minutes afterward.

The mathematical model, called "temporal clustering analysis" or TCA, enabled the scientists to effectively determine time windows of brain activation—a statistical first step to more clearly demonstrating which brain regions are involved in eating behavior.

"After eating, the human brain senses a biochemical change and then signals satiation, but precisely when this occurs is unknown," said corresponding author Dr. Jia-Hong Gao, associate professor of radiology at the Research Imaging Center. "The challenge of this functional MRI study was to map not only where but also when the brain responds following food ingestion."

The letter is titled "The temporal response of the brain after eating revealed by functional MRI." Co-authors are Dr. Peter T. Fox, director of the Research Imaging Center and professor of medicine, psychiatry and radiology; Ho-Ling Liu, a graduate student working under Dr. Gao's supervision; and Dr. Yijun Liu, assistant professor at the UF Department of Psychiatry and Brain Institute.

Scans were completed at the Research Imaging Center. Head motion caused data from three subjects to be eliminated from the analyses. Some subjects agreed to a second scan in which they drank water rather than the sugar solution; the researchers later compared the brain's response to each.