Food-Related Brain Activation Measured by fMRI in Adults with Prader-Willi Syndrome.

(1) Background: Prader-Willi syndrome (PWS) is characterized by hyperphagia, resulting in morbid obesity if not controlled. The primary aim of this study was to investigate whether PWS patients show altered activation of brain areas involved in hunger. As a secondary objective, we assessed whether there is an association between these brain areas and several endocrine and metabolic factors in the fasting state. (2) Methods: 12 PWS adults and 14 healthy controls (siblings) performed a food-related experimental task after an overnight fast while brain activation in regions of interest was measured by functional MRI. (3) Results: In controls, significantly more activation was found in the left insula (p = 0.004) and the bilateral fusiform gyrus (p = 0.003 and 0.013) when the individuals were watching food as compared to non-food pictures, which was absent in PWS patients. Moreover, in PWS adults watching food versus non-food pictures a significant negative correlation for glucose and right amygdala activation (p_fwe = 0.007) as well as a positive correlation for leptin and right anterior hippocampus/amygdala activation (p_fwe = 0.028) was demonstrated. No significant associations for the other hormonal and metabolic factors were found. (4) Conclusions: PWS individuals show aberrant food-related brain activation in the fasting state. Leptin is associated with activation within the neural motivation/reward circuitry, while the opposite is true for glucose.