Background: Major depressive disorder (MDD) patients face an increased risk of developing cognitive impairments. One of the prominent cognitive impairments in MDD patients is verbal fluency deficit. Nonetheless, it is not clear which vulnerable brain region in MDD is interactively linked to verbal fluency deficit. It is important to gain an improved understanding for verbal fluency deficit in MDD. Methods: Thirty-four MDD patients and 34 normal controls (NCs) completed resting-state fMRI (rs-fMRI) scan and a set of verbal fluency tests (semantic VFT and phonemic VFT). Fourteen brain regions from five brain networks/systems (central executive network, default mode network, salience network, limbic system, cerebellum) based on their vital role in MDD neuropathology were selected as seeds for functional connectivity (FC) analyses with the voxels in the whole brain. Finally, correlations between the z-score of the FCs from clusters showing significant between-group difference and z-score of the VFTs were calculated using Pearson correlation analyses. Results: Increased FCs in MDD patients vs. NCs were identified between the bilateral posterior cingulate cortex (PCC) and the right inferior frontal gyrus (triangular part), in which the increased FC between the right PCC and the right inferior frontal gyrus (triangular part) was positively correlated with the z score of phonemic VFT in the MDD patients. Moreover, decreased FCs were identified between the right hippocampal gyrus and PCC, as well as left cerebellum Crus II and right parahippocampal gyrus in MDD patients vs. NCs. Conclusions: The MDD patients have altered FCs among key brain regions in the default mode network, the central executive network, the limbic system, and the cerebellum. The increased FC between the right PCC and the right inferior frontal gyrus (triangular part) may be useful to better characterize pathophysiology of MDD and functional correlates of the phonemic verbal fluency deficit in MDD.

中文翻译：

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后扣带皮层的异常功能连接与重度抑郁症的音素言语流畅性缺陷相关。

背景：重度抑郁症 (MDD) 患者面临发生认知障碍的风险增加。MDD 患者的显着认知障碍之一是语言流畅性缺陷。尽管如此，目前尚不清楚 MDD 中哪个易受攻击的大脑区域与语言流畅性缺陷交互相关。重要的是要更好地理解 MDD 中的语言流畅性缺陷。方法：34 名 MDD 患者和 34 名正常对照 (NC) 完成静息态 fMRI (rs-fMRI) 扫描和一组语言流畅性测试（语义 VFT 和音素 VFT）。来自五个大脑网络/系统（中央执行网络、默认模式网络、显着网络、边缘系统、小脑）基于它们在 MDD 神经病理学中的重要作用被选为对整个大脑中的体素进行功能连接 (FC) 分析的种子。最后，使用 Pearson 相关分析计算来自显示显着组间差异的集群的 FC 的 z 分数与 VFT 的 z 分数之间的相关性。结果：在双侧后扣带回皮层 (PCC) 和右侧额下回 (三角形部分) 之间发现 MDD 患者与 NCs 相比 FC 增加，其中右侧 PCC 和右侧额下回 (三角形部分) 之间的 FC 增加) 与 MDD 患者中音素 VFT 的 z 分数呈正相关。此外，在右侧海马回和 PCC 之间发现了减少的 FC，以及 MDD 患者与 NC 患者的左侧小脑 Crus II 和右侧海马旁回。结论：MDD 患者在默认模式网络、中枢执行网络、边缘系统和小脑的关键大脑区域中改变了 FC。右侧 PCC 和右侧额下回（三角形部分）之间增加的 FC 可能有助于更好地表征 MDD 的病理生理学和 MDD 中音素语言流畅性缺陷的功能相关性。