Hinton E C, Holland A J, Gellatly M S N, Soni S, Owen A M
Section of Developmental Psychiatry, Department of Psychiatry, University of Cambridge, UK.
J Intellect Disabil Res. 2006 Sep;50(Pt 9):633-42. doi: 10.1111/j.1365-2788.2006.00812.x.
Research into the excessive eating behaviour associated with Prader-Willi syndrome (PWS) to date has focused on homeostatic and behavioural investigations. The aim of this study was to examine the role of the reward system in such eating behaviour, in terms of both the pattern of food preferences and the neural substrates of incentive in the amygdala and orbitofrontal cortex (OFC).
Participants with PWS (n = 18) were given a food preference interview to examine food preferences and to inform the food-related incentive task to be conducted during the neuroimaging. Thirteen individuals with PWS took part in the positron emission tomography (PET) study, the design of which was based on a previous study of non-obese, non-PWS controls. For the task, participants were asked to consider photographs of food and to choose the food they would most like to eat in two conditions, one of high and one of low incentive foods, tailored to each participant's preferences. For comparison of the food preference data, 12 non-PWS individuals were given one part of the interview.
Individuals with PWS expressed relative liking of different foods and showed preferences that were consistent over time, particularly for sweet foods. The participants with PWS did give the foods in the high incentive condition a significantly higher incentive value than the foods in the low incentive condition. However, activation of the amygdala and medial OFC was not associated with the prospect of highly valued foods as predicted in those with PWS.
It would appear that incentive motivation alone plays a less powerful role in individuals with PWS than in those without the syndrome. This is likely to be due to the overriding intrinsic drive to eat because of a lack of satiety in those with PWS, and the impact of this on activity in the incentive processing regions of the brain. Activity in such reward areas may not then function to guide behaviour selectively towards the consumption of high preference foods.
迄今为止，对与普拉德-威利综合征（PWS）相关的过度进食行为的研究主要集中在稳态和行为调查方面。本研究的目的是从食物偏好模式以及杏仁核和眶额皮质（OFC）中激励的神经基质方面，研究奖励系统在这种进食行为中的作用。
对患有PWS的参与者（n = 18）进行食物偏好访谈，以检查食物偏好，并为神经成像期间进行的与食物相关的激励任务提供信息。13名患有PWS的个体参与了正电子发射断层扫描（PET）研究，该研究的设计基于先前对非肥胖、非PWS对照的研究。在任务中，要求参与者查看食物照片，并在两种情况下选择他们最想吃的食物，一种是高激励食物，一种是低激励食物，这两种情况是根据每个参与者的偏好量身定制的。为了比较食物偏好数据，12名非PWS个体接受了访谈的一部分。
患有PWS的个体表现出对不同食物的相对喜好，并且随着时间的推移表现出一致的偏好，特别是对甜食。患有PWS的参与者确实给予高激励条件下的食物比低激励条件下的食物显著更高的激励价值。然而，杏仁核和内侧OFC的激活与PWS患者中预测的高价值食物的前景无关。
似乎仅激励动机在患有PWS的个体中所起的作用比在没有该综合征的个体中要小。这可能是由于PWS患者缺乏饱腹感而导致的压倒性内在进食驱动力，以及这对大脑激励处理区域活动的影响。那么，此类奖励区域的活动可能无法起到将行为选择性地引导向高偏好食物消费的作用。
