Network-Level Structural Abnormalities of Cerebral Cortex in Type 1 Diabetes Mellitus

Type 1 diabetes mellitus (T1DM) usually begins in childhood and adolescence and causes lifelong damage to several major organs including the brain. Despite increasing evidence of T1DM-induced structural deficits in cortical regions implicated in higher cognitive and emotional functions, little is known whether and how the structural connectivity between these regions is altered in the T1DM brain. Using inter-regional covariance of cortical thickness measurements from high-resolution T1-weighted magnetic resonance data, we examined the topological organizations of cortical structural networks in 81 T1DM patients and 38 healthy subjects. We found a relative absence of hierarchically high-level hubs in the prefrontal lobe of T1DM patients, which suggests ineffective top-down control of the prefrontal cortex in T1DM. Furthermore, inter-network connections between the strategic/executive control system and systems subserving other cortical functions including language and mnemonic/emotional processing were also less integrated in T1DM patients than in healthy individuals. The current results provide structural evidence for T1DM-related dysfunctional cortical organization, which specifically underlie the top-down cognitive control of language, memory, and emotion.

1型糖尿病（Type 1 diabetes mellitus, T1DM）通常起病于儿童期与青少年阶段，可造成包括大脑在内的多个重要器官的终身性损伤。尽管已有越来越多的研究证据表明，T1DM会对参与高级认知与情绪功能的皮层区域造成结构损伤，但目前对于T1DM患者大脑中这些区域之间的结构连接是否发生改变、以及具体的改变机制仍知之甚少。本研究借助高分辨率T1加权磁共振成像数据中皮层厚度测量值的区域间协方差，对81例T1DM患者与38例健康受试者的大脑皮层结构网络拓扑组织特征展开了分析。研究结果显示，T1DM患者的前额叶皮层中缺乏层级化的高级枢纽节点，这提示T1DM患者的前额叶皮层自上而下调控功能存在缺陷。此外，与健康受试者相比，T1DM患者的策略/执行控制系统与支持其他皮层功能的系统（包括语言、记忆与情绪加工相关系统）之间的网络间连接整合程度也显著更低。本研究结果为T1DM相关的皮层组织功能异常提供了结构层面的实验证据，这类异常正是语言、记忆与情绪的自上而下认知调控功能受损的结构基础。