Dietrich A, Hollmann M, Mathar D, Villringer A, Horstmann A
Department of Neurology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.
IFB Adiposity Diseases, Leipzig University Medical Center, Leipzig, Germany.
Int J Obes (Lond). 2016 Jun;40(6):982-9. doi: 10.1038/ijo.2016.28. Epub 2016 Feb 17.
Food craving is a driving force for overeating and obesity. However, the relationship between brain mechanisms involved in its regulation and weight status is still an open issue. Gaps in the studied body mass index (BMI) distributions and focusing on linear analyses might have contributed to this lack of knowledge. Here, we investigated brain mechanisms of craving regulation using functional magnetic resonance imaging in a balanced sample including normal-weight, overweight and obese participants. We investigated associations between characteristics of obesity, eating behavior and regulatory brain function focusing on nonlinear relationships.
SUBJECTS/METHODS: Forty-three hungry female volunteers (BMI: 19.4-38.8 kg m(-2), mean: 27.5±5.3 s.d.) were presented with visual food stimuli individually pre-rated according to tastiness and healthiness. The participants were instructed to either admit to the upcoming craving or regulate it. We analyzed the relationships between regulatory brain activity as well as functional connectivity and BMI or eating behavior (Three-Factor Eating Questionnaire, scales: Cognitive Restraint, Disinhibition).
During regulation, BMI correlated with brain activity in the left putamen, amygdala and insula in an inverted U-shaped manner. Functional connectivity between the putamen and the dorsolateral prefrontal cortex (dlPFC) correlated positively with BMI, whereas that of amygdala with pallidum and lingual gyrus was nonlinearly (U-shaped) associated with BMI. Disinhibition correlated negatively with the strength of functional connectivity between amygdala and dorsomedial prefrontal (dmPFC) cortex as well as caudate.
This study is the first to reveal quadratic relationships of food-related brain processes and BMI. Reported nonlinear associations indicate inverse relationships between regulation-related motivational processing in the range of normal weight/overweight compared with the obese range. Connectivity analyses suggest that the need for top-down (dlPFC) adjustment of striatal value representations increases with BMI, whereas the interplay of self-monitoring (dmPFC) or eating-related strategic action planning (caudate) and salience processing (amygdala) might be hampered with high Disinhibition.
食物渴望是暴饮暴食和肥胖的驱动力。然而，参与其调节的脑机制与体重状况之间的关系仍是一个悬而未决的问题。所研究的体重指数（BMI）分布存在差距，且专注于线性分析，这可能导致了这方面知识的匮乏。在此，我们使用功能磁共振成像在一个包括正常体重、超重和肥胖参与者的均衡样本中研究了渴望调节的脑机制。我们研究了肥胖特征、饮食行为与调节性脑功能之间的关联，重点关注非线性关系。
受试者/方法：43名饥饿的女性志愿者（BMI：19.4 - 38.8 kg·m⁻²，平均：27.5 ± 5.3标准差）分别观看根据美味程度和健康程度预先评级的视觉食物刺激。参与者被指示要么承认即将出现的渴望，要么对其进行调节。我们分析了调节性脑活动以及功能连接与BMI或饮食行为（三因素饮食问卷，量表：认知抑制、去抑制）之间的关系。
在调节过程中，BMI与左侧壳核、杏仁核和脑岛的脑活动呈倒U形相关。壳核与背外侧前额叶皮层（dlPFC）之间的功能连接与BMI呈正相关，而杏仁核与苍白球和舌回之间的功能连接与BMI呈非线性（U形）相关。去抑制与杏仁核和背内侧前额叶（dmPFC）皮层以及尾状核之间功能连接的强度呈负相关。
本研究首次揭示了与食物相关的脑过程和BMI之间的二次关系。所报道的非线性关联表明，与肥胖范围相比，正常体重/超重范围内与调节相关的动机处理之间存在反比关系。连接性分析表明，随着BMI的增加，对纹状体价值表征进行自上而下（dlPFC）调整的需求增加，而自我监测（dmPFC）或与饮食相关的战略行动规划（尾状核）和显著性处理（杏仁核）之间的相互作用可能会因高去抑制而受到阻碍。
