Objectives

To examine the role of the hippocampus in stress regulation in older adults with amnestic mild cognitive impairment (aMCI).

Methods

This study combined resting-state functional MRI, structural MRI, self-reported chronic stress exposure, and an electrocardiography-based acute stress protocol to compare aMCI group (n = 17) to their cognitively healthy counterparts (HC, n = 22).

Results

For the entire sample, there was a positive correlation between chronic stress exposure and acute stress regulation. The aMCI group showed significantly smaller volumes in the right hippocampus than HC. The two groups did not differ in chronic stress exposure or acute stress regulation. In the HC group, the left hippocampal connectivity with inferior parietal lobe was significantly correlated with both the chronic stress and acute stress. In the aMCI group, the left hippocampal connectivity with both the right insula and the left precentral gyrus was significantly correlated to chronic stress exposure and acute stress regulation. Additionally, the left hippocampal connectivity with right insula significantly mediated the relationship between chronic stress exposure and acute stress regulation in aMCI group.

Conclusions

Extra hippocampal networks may be recruited as compensation to attend the maintenance of relatively normal stress regulation in aMCI by alleviating the detrimental effects of chronic stress exposure on acute stress regulation.

中文翻译：

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海马网络在遗忘型轻度认知障碍患者压力调节中的中介作用。

目标

研究海马在患有遗忘性轻度认知障碍 (aMCI) 的老年人压力调节中的作用。

方法

本研究结合静息状态功能 MRI、结构 MRI、自我报告的慢性压力暴露和基于心电图的急性压力方案，将 aMCI 组（n = 17）与认知健康的对应组（HC，n = 22）进行比较。

结果

对于整个样本，慢性应激暴露与急性应激调节呈正相关。aMCI 组的右侧海马体积明显小于 HC。两组在慢性压力暴露或急性压力调节方面没有差异。在HC组中，左侧海马与下顶叶的连通性与慢性应激和急性应激均显着相关。在 aMCI 组中，左侧海马与右侧岛叶和左侧中央前回的连接与慢性应激暴露和急性应激调节显着相关。此外，左侧海马与右侧岛叶的连接显着介导了 aMCI 组慢性应激暴露与急性应激调节之间的关系。

结论

通过减轻慢性压力暴露对急性压力调节的不利影响，可以招募额外的海马网络作为补偿，以参与维持 aMCI 中相对正常的压力调节。