PURPOSE Mild cognitive impairment (MCI) in Parkinson's disease (PD) is related to the disrupted connectivity in networks involved in cognition, primarily in the default mode network (DMN). The DMN contains a midline core and two distinct subsystems (dorsal medial prefrontal cortex (DMPFC) and medial temporal lobe (MTL) subsystems). METHODS The strength of functional connectivity (FCS) in intra- and inter-subsystems of DMN and the regional FCS were compared between any two groups from 28 drug-naïve PD patients with MCI (PD-MCI), 19 drug-naïve PD patients with cognitive unimpaired (PD-CU), and 28 age- and sex-matched healthy controls (HCs) by using the nonparametric permutation method (10,000 permutations) with age, sex, and education as covariates and False Discovery Rate (FDR) correction. RESULTS For intra-subsystems, the decreased FCS was only detected in the DMPFC subsystem of PD-MCI patients compared with HCs. For inter-subsystems, PD-MCI patients displayed decreased FCS between the posterior cingulate cortex (PCC) and DMPFC subsystem compared with HCs. Furthermore, the temporal parietal junction (TPJ) in the DMPFC subsystem showed decreased regional FCS in the PD-MCI subgroup relative to the HC group. No significant change of FCS was found between PD-MCI and PD-CU patients, and between PD-CU patients and HCs. The sum of FCS values within the DMPFC subsystem and FCS values between the PCC and DMPFC subsystem had a significant power to distinguish PD-MCI patients from PD-CU patients (area under curve (AUC) = 0.703). CONCLUSION The DMPFC subsystem was predominantly disrupted in the PD-MCI subgroup and may have the potential to discriminate PD with MCI.

中文翻译：

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初治帕金森氏病伴轻度认知障碍的默认模式网络子系统的主要破坏。

目的帕金森氏病（PD）中的轻度认知障碍（MCI）与参与认知的网络（主要是默认模式网络（DMN））中的连接中断有关。DMN包含中线核心和两个不同的子系统（背内侧前额叶皮层（DMPFC）和内侧颞叶（MTL）子系统）。方法比较了28例无药物PD的MCI（PD-MCI），19例无药物PD的DMN的系统内和系统间DMN子系统之间以及区域FCS的强度。通过使用非参数排列方法（10,000个排列），将年龄，性别和教育程度作为协变量和错误发现率（FDR）校正，使用无参数认知障碍（PD-CU）和28个年龄和性别匹配的健康对照（HCs）。结果对于内部子系统，与HCs相比，仅在PD-MCI患者的DMPFC子系统中检测到FCS降低。对于子系统间，PD-MCI患者的后扣带回皮质（PCC）和DMPFC子系统之间的FCS与HC相比降低。此外，相对于HC组，DMPFC子系统中的颞顶交界处（TPJ）显示PD-MCI子组中的区域FCS减少。在PD-MCI和PD-CU患者之间以及PD-CU患者和HCs之间未发现FCS的显着变化。DMPFC子系统中的FCS值之和以及PCC和DMPFC子系统之间的FCS值具有区分PD-MCI患者和PD-CU患者的显着能力（曲线下面积（AUC）= 0.703）。结论DMPFC子系统在PD-MCI亚组中主要受到破坏，可能具有区分PD与MCI的潜力。