Spetter Maartje S, de Graaf Cees, Mars Monica, Viergever Max A, Smeets Paul A M
Image Sciences Institute, University Medical Center Utrecht, Utrecht, The Netherlands.
Division of Human Nutrition, Wageningen University, Wageningen, The Netherlands.
PLoS One. 2014 Mar 10;9(3):e90872. doi: 10.1371/journal.pone.0090872. eCollection 2014.
During food consumption the brain integrates multiple interrelated neural and hormonal signals involved in the regulation of food intake. Factors influencing the decision to stop eating include the foods' sensory properties, macronutrient content, and volume, which in turn affect gastric distention and appetite hormone responses. So far, the contributions of gastric distention and oral stimulation by food on brain activation have not been studied. The primary objective of this study was to assess the effect of gastric distention with an intra-gastric load and the additional effect of oral stimulation on brain activity after food administration. Our secondary objective was to study the correlations between hormone responses and appetite-related ratings and brain activation. Fourteen men completed three functional magnetic resonance imaging sessions during which they either received a naso-gastric infusion of water (stomach distention), naso-gastric infusion of chocolate milk (stomach distention + nutrients), or ingested chocolate-milk (stomach distention + nutrients + oral exposure). Appetite ratings and blood parameters were measured at several time points. During gastric infusion, brain activation was observed in the midbrain, amygdala, hypothalamus, and hippocampus for both chocolate milk and water, i.e., irrespective of nutrient content. The thalamus, amygdala, putamen and precuneus were activated more after ingestion than after gastric infusion of chocolate milk, whereas infusion evoked greater activation in the hippocampus and anterior cingulate. Moreover, areas involved in gustation and reward were activated more after oral stimulation. Only insulin responses following naso-gastric infusion of chocolate milk correlated with brain activation, namely in the putamen and insula. In conclusion, we show that normal (oral) food ingestion evokes greater activation than gastric infusion in stomach distention and food intake-related brain areas. This provides neural evidence for the importance of sensory stimulation in the process of satiation.
ClinicalTrials.gov NCT01644539.
在进食过程中，大脑整合多种与食物摄入调节相关的相互关联的神经和激素信号。影响停止进食决定的因素包括食物的感官特性、宏量营养素含量和体积，这些因素进而影响胃扩张和食欲激素反应。到目前为止，胃扩张和食物对口腔的刺激对大脑激活的作用尚未得到研究。本研究的主要目的是评估胃内负荷引起的胃扩张以及食物摄入后口腔刺激对大脑活动的额外影响。我们的次要目的是研究激素反应与食欲相关评分及大脑激活之间的相关性。14名男性完成了三次功能磁共振成像检查，期间他们分别接受鼻胃管输注水（胃扩张）、鼻胃管输注巧克力牛奶（胃扩张 + 营养素）或摄入巧克力牛奶（胃扩张 + 营养素 + 口腔接触）。在几个时间点测量了食欲评分和血液参数。在胃内输注期间，无论是巧克力牛奶还是水，在中脑、杏仁核、下丘脑和海马体中均观察到大脑激活，即与营养素含量无关。与胃内输注巧克力牛奶相比，摄入后丘脑、杏仁核、壳核和楔前叶的激活程度更高，而输注在海马体和前扣带回中引起的激活程度更大。此外，在口腔刺激后，参与味觉和奖赏的区域激活程度更高。仅鼻胃管输注巧克力牛奶后的胰岛素反应与大脑激活相关，即在壳核和脑岛。总之，我们表明正常（经口）进食在胃扩张和食物摄入相关脑区引起的激活比胃内输注更大。这为饱腹感过程中感觉刺激的重要性提供了神经学证据。
ClinicalTrials.gov NCT01644539。
