Division of Endocrinology, Metabolism and Diabetes, Department of Medicine, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, CO 80045, USA.
Physiol Behav. 2013 Feb 17;110-111:122-8. doi: 10.1016/j.physbeh.2013.01.002. Epub 2013 Jan 10.
Despite living in an obesogenic environment, some individuals maintain a thin phenotype compared to the majority who are at risk for weight gain and obesity. Understanding how these different phenotypes regulate energy intake is critical. The objective of this study was to examine the differences in neuronal response to visual food cues in adults recruited as either obesity-resistant (OR) or obesity-prone (OP) based on self-identification, BMI, and personal/family weight history. 25 OR and 28 OP individuals were studied after 4 days of eucaloric energy intake. Functional magnetic resonance imaging (fMRI) was performed in the fasted and acute fed states (30 min after a test meal) while subjects viewed images of foods of high hedonic value and neutral non-food objects. Measures of appetite using visual analog scales were performed before and every 30 min after the test meal for 3 h. In the fasted state, food as compared to nonfood images elicited significant response in the insula, somatosensory cortex, parietal cortex, and visual cortex in both OR and OP. The acute fed state resulted in significant attenuation of these and other brain areas in the OR but not OP individuals. Furthermore, OP as compared to OR individuals showed greater activation of medial and anterior prefrontal cortex (PFC) in response to the test meal. Adjusting for fat mass did not impact these results. Attenuation of insula/PFC response to food images in the fed state was associated with greater reductions in hunger. These findings suggest that individuals prone to weight gain and obesity have altered neuronal responses to food cues in brain regions known to be important in energy intake regulation. These altered responses may represent an important mechanism contributing to excess energy intake and risk for obesity.
尽管生活在肥胖环境中，一些个体与大多数易增重和肥胖的个体相比，保持着瘦体型。了解这些不同表型如何调节能量摄入是至关重要的。本研究的目的是研究根据自我认同、BMI 和个人/家庭体重史，将肥胖抵抗（OR）或肥胖易感（OP）个体分为两组，观察他们在视觉食物线索刺激下神经元反应的差异。在 4 天的能量摄入平衡后，对 25 名 OR 和 28 名 OP 个体进行了研究。在空腹和急性进食状态下（测试餐后 30 分钟）进行功能磁共振成像（fMRI），同时观察高愉悦值食物和中性非食物图像。在测试餐后 3 小时内，每 30 分钟进行一次视觉模拟量表评估食欲。在空腹状态下，与非食物图像相比，食物图像会引起 OR 和 OP 个体的岛叶、躯体感觉皮层、顶叶皮层和视觉皮层的显著反应。在急性进食状态下，OR 个体而非 OP 个体的这些和其他大脑区域的反应显著减弱。此外，与 OR 个体相比，OP 个体在对测试餐的反应中显示出内侧和前前额叶皮层（PFC）的更大激活。调整脂肪量并不影响这些结果。进食状态下对食物图像的岛叶/PFC 反应的减弱与饥饿感的更大减少有关。这些发现表明，易增重和肥胖的个体对大脑中与能量摄入调节有关的区域中食物线索的神经元反应发生改变。这些改变的反应可能是导致能量摄入过多和肥胖风险的重要机制。
