Background: Subjective Memory Impairment (SMI) may tremendously increase the risk of Alzheimer’s Disease (AD). The full understanding of the neuromechanism of SMI will shed light on the early intervention of AD.

Methods: In the current study, 23 Healthy Controls (HC), 22 SMI subjects and 24 amnestic Mild Cognitive Impairment (aMCI) subjects underwent the comprehensive neuropsychological assessment and the resting-state functional magnetic resonance imaging scan. The difference in the connectivity of the Default Mode Network (DMN) and Functional Connectivity (FC) from the Region of Interest (ROI) to the whole brain were compared, respectively.

Results: The results showed that HC and SMI subjects had significantly higher connectivity in the region of the precuneus area compared to aMCI subjects. However, from this region to the whole brain, SMI and aMCI subjects had significant FC decrease in the right anterior cingulum, left superior frontal and left medial superior frontal gyrus compared to HC. In addition, this FC change was significantly correlated with the cognitive function decline in participants.

Conclusion: Our study indicated that SMI subjects had relatively intact DMN connectivity but impaired FC between the anterior and posterior brain. The findings suggest that long-distance FC is more vulnerable than the short ones in the people with SMI.

背景：主观记忆障碍 (SMI) 可能会极大地增加阿尔茨海默病 (AD) 的风险。充分了解SMI的神经机制将为AD的早期干预提供启示。

方法：在目前的研究中，23 名健康对照 (HC)、22 名 SMI 受试者和 24 名遗忘型轻度认知障碍 (aMCI) 受试者接受了全面的神经心理学评估和静息状态功能磁共振成像扫描。分别比较了从感兴趣区域 (ROI) 到整个大脑的默认模式网络 (DMN) 和功能连接 (FC) 的连接差异。

结果：结果表明，与 aMCI 受试者相比，HC 和 SMI 受试者在楔前叶区域具有显着更高的连通性。然而，从该区域到整个大脑，与 HC 相比，SMI 和 aMCI 受试者的右前扣带回、左上额叶和左内侧额上回的 FC 显着减少。此外，这种 FC 变化与参与者的认知功能下降显着相关。

结论：我们的研究表明 SMI 受试者具有相对完整的 DMN 连接，但前脑和后脑之间的 FC 受损。研究结果表明，在 SMI 患者中，长距离 FC 比短距离 FC 更脆弱。