PWSA (USA) Research Grant Approved March 2005
“Functional Magnetic Resonance Imaging of Reduced Satiety in Prader-Willi Syndrome and Obesity”
(Drs. J Miller, DJ Driscoll and AP Goldstone) Gainesville, FL

The pathways within the brain that control food intake are regulated by many factors, including input from other parts of the brain and hormonal signals from the gut. These pathways can be studied using functional Magnetic Resonance Imaging (fMRI). Functional MRI is a powerful technique which allows one to non-invasively study the activity of the brain in response to stimuli, such as food. Previous brain imaging studies have shown that there is an increased reward response to viewing pictures of food in individuals with Prader-Willi syndrome (PWS) which may result in abnormalities of appetite control.
This study seeks to identify which abnormalities in the appetite regulating hormonal-brain pathways lead to excessive food intake in PWS, and to see if any of those abnormalities can be changed with an increased meal size. Participants in the study will have two fMRI studies on two separate days, with the first scan on each day being done before they eat and the second scan being done after either a large breakfast or a small breakfast. Blood draws will be done during the fMRI scans for hormonal measurements. During and after each of the scans, hunger will be measured by having the participants complete an appetite scale and by measuring the number of sandwich quarters they eat two hours after the final fMRI scan.
We expect to find key differences in the hormonal-brain pathways in response to different meal sizes which will increase our understanding of the factors involved in the sensations of hunger and fullness in individuals with PWS. These findings can then serve as the basis for future studies in PWS which will investigate treatments targeted to the specific brain pathway and hormonal abnormalities found in this study.

edited: 08/19/2008