Obesity has a profound impact on metabolic health thereby adversely affecting brain structure and function. However, the majority of previous studies used a single structural index to investigate the link between brain structure and body mass index (BMI), which hinders our understanding of structural covariance between regions in obesity. This study aimed to examine the relationship between macroscale cortical organization and BMI using novel morphometric similarity networks (MSNs). The individual MSNs were first constructed from individual eight multimodal cortical morphometric features between brain regions. Then the relationship between BMI and MSNs within the discovery sample of 434 participants was assessed. The key findings were further validated in an independent sample of 192 participants. We observed that the lateral non-reward orbitofrontal cortex (lOFC) exhibited decoupling (i.e., reduction in integration) in obesity, which was mainly manifested by its decoupling with the cognitive systems (i.e., DMN and FPN) while the medial reward orbitofrontal cortex (mOFC) showed de-differentiation (i.e., decrease in distinctiveness) in obesity, which was mainly represented by its de-differentiation with the cognitive and attention systems (i.e., DMN and VAN). Additionally, the lOFC showed de-differentiation with the visual system in obesity, while the mOFC showed decoupling with the visual system and hyper-coupling with the sensory-motor system in obesity. As an important first step in revealing the role of underlying structural covariance in body mass variability, the present study presents a novel mechanism that underlies the reward-control interaction imbalance in obesity, thus can inform future weight-management approaches.

中文翻译：

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肥胖患者内侧奖励和外侧非奖励眶额皮层回路的形态相似性的相反变化

肥胖对代谢健康产生深远影响，从而对大脑结构和功能产生不利影响。然而，之前的大多数研究都使用单一的结构指数来研究大脑结构和体重指数（BMI）之间的联系，这阻碍了我们对肥胖区域之间结构协方差的理解。本研究旨在利用新型形态相似性网络 (MSN) 来研究宏观皮质组织与 BMI 之间的关系。各个 MSN 首先是根据大脑区域之间的八个多模式皮层形态测量特征构建的。然后评估 434 名参与者的发现样本中 BMI 和 MSN 之间的关系。主要发现在 192 名参与者的独立样本中得到了进一步验证。我们观察到，外侧非奖励眶额皮质（lOFC）在肥胖中表现出脱钩（即整合减少），这主要表现为其与认知系统（即DMN和FPN）的脱钩，而内侧奖励眶额皮质（ mOFC）在肥胖中表现出去分化（即独特性降低），这主要表现为其与认知和注意系统（即DMN和VAN）的去分化。此外，lOFC在肥胖症中表现出与视觉系统的去分化，而mOFC在肥胖症中表现出与视觉系统的解耦以及与感觉运动系统的超耦合。作为揭示潜在结构协方差在体重变异中的作用的重要第一步，本研究提出了一种新的机制，该机制是肥胖中奖赏控制相互作用失衡的基础，因此可以为未来的体重管理方法提供信息。