Rothemund Yvonne, Preuschhof Claudia, Bohner Georg, Bauknecht Hans-Christian, Klingebiel Randolf, Flor Herta, Klapp Burghard F
Center for Internal Medicine and Dermatology, Department of Psychosomatic Medicine, Charité - University Medicine, Charité Platz 1, 10117 Berlin, Germany.
Neuroimage. 2007 Aug 15;37(2):410-21. doi: 10.1016/j.neuroimage.2007.05.008. Epub 2007 May 18.
The neural systems regulating food intake in obese individuals remain poorly understood. Previous studies applied positron emission tomography and manipulated hunger and satiety to investigate differences in appetitive processing between obese and normal-weight individuals. However, it is not known whether manipulation of stimulus value may yield different neural activity in obese as compared to control subjects when intrinsic physiological states are kept constant. We used functional magnetic resonance imaging to investigate 13 obese and 13 normal-weight subjects and manipulated food motivation by presenting visual food stimuli differing in their caloric content and energy density. In contrast to controls, obese women selectively activated the dorsal striatum while viewing high-caloric foods. Moreover, in the high-calorie condition body mass index (BMI) predicted activation in the dorsal striatum, anterior insula, claustrum, posterior cingulate, postcentral and lateral orbitofrontal cortex. The results indicate that in obese individuals simple visual stimulation with food stimuli activates regions related to reward anticipation and habit learning (dorsal striatum). Additionally, high-calorie food images yielded BMI-dependent activations in regions associated with taste information processing (anterior insula and lateral orbitofrontal cortex), motivation (orbitofrontal cortex), emotion as well as memory functions (posterior cingulate). Collectively, the results suggest that the observed activation is independent of the physiological states of hunger and satiation, and thus may contribute to pathological overeating and obesity. Some of the observed activations (dorsal striatum, orbitofrontal cortex) are likely to be dopamine-mediated.
调节肥胖个体食物摄入的神经系统仍未得到充分理解。先前的研究应用正电子发射断层扫描并控制饥饿和饱腹感，以调查肥胖个体与正常体重个体在食欲加工方面的差异。然而，当内在生理状态保持恒定时，与对照受试者相比，刺激值的操控是否会在肥胖个体中产生不同的神经活动尚不清楚。我们使用功能磁共振成像来研究13名肥胖受试者和13名正常体重受试者，并通过呈现热量含量和能量密度不同的视觉食物刺激来操控食物动机。与对照组不同，肥胖女性在观看高热量食物时选择性地激活了背侧纹状体。此外，在高热量条件下，体重指数（BMI）预测了背侧纹状体、前脑岛、屏状核、后扣带回、中央后回和外侧眶额皮质的激活。结果表明，在肥胖个体中，用食物刺激进行简单的视觉刺激会激活与奖励预期和习惯学习相关的区域（背侧纹状体）。此外，高热量食物图像在与味觉信息处理（前脑岛和外侧眶额皮质）、动机（眶额皮质）、情绪以及记忆功能（后扣带回）相关的区域产生了与BMI相关的激活。总体而言，结果表明观察到的激活与饥饿和饱腹感的生理状态无关，因此可能导致病理性暴饮暴食和肥胖。一些观察到的激活（背侧纹状体、眶额皮质）可能是由多巴胺介导的。
