Another new article is just out on brain imaging during eating in people with PWS, and it better defines the changes in the brain associated with feeling full after a meal. The brain images show the lack of those changes in most people with PWS, even after a very high calorie meal.
It probably comes as no surprise that the imaging suggests that the feeling of fullness does not get transmitted to the brain appropriately in those with PWS. Also not surprising, the people with PWS returned to a feeling of hunger much earlier than expected following the high calorie meal. Interestingly in this study, about half of the subjects did show some activation of the medial orbitalfrontal area of the brain after the high calorie meal, and these also expressed (verbally) that they felt full. The half that did show activation after the high calorie meal did not differ in any detectable way from those who did not show activation (ie, they were not different with respect to UPD or del, male or female, overweight vs. not so overweight, etc)
This paper nicely shows the promise of new imaging technology in being able to monitor feelings of hunger and satiety in real time. This and other imaging technology is likely to be helpful in better understanding the deficiencies in the brain of those with PWS to detect fullness, and also may prove useful in evaluating the efficacy of drugs developed to address this problem.
Neural representations of hunger and satiety in Prader-Willi syndrome . Hinton EC, Holland AJ, Gellatly MS, Soni S, Patterson M, Ghatei MA, Owen AM. International Journal of Obesity (2006) 30, 313–321. doi:10.1038/sj.ijo.0803128
