Institute of Pathophysiology and Immunology, Center for Molecular Medicine, Medical University of Graz, Graz, Austria.
Obesity (Silver Spring). 2010 Aug;18(8):1552-7. doi: 10.1038/oby.2010.26. Epub 2010 Feb 18.
Responsiveness to food cues, especially those associated with high-calorie nutrients may be a factor underlying obesity. An increased motivational potency of foods appears to be mediated in part by the hippocampus. To clarify this, we investigated by means of 3-T magnetic resonance imaging (MRI) the activation of the hippocampus and associated brain structures in response to pictures of high-calorie and low-calorie foods in 12 obese and 12 normal-weight adolescents. To investigate the relationship between neuronal activation patterns (e.g., hippocampus) to the caloric content of food images and plasma insulin levels, we performed a multiple regression analysis. Interestingly, a significant positive correlation between fasting plasma levels of insulin, waist circumference, and right hippocampal activation was seen after stimulation with high-caloric food images. BMI values did not correlate significantly with the hippocampal activation. On the other hand, we found a significant negative correlation in response to high-caloric food images and the plasma levels of insulin in the medial right gyrus frontalis superior and in the left thalamus. In summary, our data show that insulin is importantly involved in the central regulation of food intake. The significant positive relationship between hippocampal activation after stimulation with high-caloric food images, plasma insulin levels, and waist circumference suggests a permissive role of insulin signaling pathways in the hippocampal control of eating behavior. Interestingly, only the waist circumference, as a main indicator of abdominal obesity, correlated significantly with the hippocampal activation patterns, and not the BMI.
对食物线索的反应能力，特别是那些与高热量营养物质相关的线索，可能是肥胖的一个潜在因素。食物的激励作用似乎部分是由海马体介导的。为了阐明这一点，我们通过 3-T 磁共振成像（MRI）技术，研究了 12 名肥胖青少年和 12 名正常体重青少年在看到高热量和低热量食物图片时，海马体和相关大脑结构的激活情况。为了研究神经元激活模式（例如海马体）与食物图像热量含量之间的关系，我们进行了多元回归分析。有趣的是，在刺激高热量食物图片后，空腹胰岛素水平、腰围和右侧海马体激活之间存在显著正相关。BMI 值与海马体激活没有显著相关性。另一方面，我们发现右侧额上回和左侧丘脑在对高热量食物图片的反应中，胰岛素水平与海马体激活之间存在显著负相关。总之，我们的数据表明，胰岛素在食物摄入的中枢调节中起着重要作用。刺激高热量食物图片后，海马体激活、血浆胰岛素水平和腰围之间存在显著正相关，这表明胰岛素信号通路在海马体控制进食行为中具有许可作用。有趣的是，只有腰围作为腹部肥胖的主要指标与海马体激活模式显著相关，而 BMI 则没有。
