遗忘型轻度认知障碍患者内颞叶记忆网络动态变化研究

遗忘型轻度认知障碍（amnesic mild cognitive impairment, aMCI）是介于正常老化与阿尔茨海默病（Alzheimer’s disease, AD）之间的过渡阶段，每年约有15%的aMCI患者转化为AD，这一演变过程是否伴随脑功能连接的动态变化仍不清楚。内颞叶是AD神经病理最早累及的脑区，内颞叶前部网络（AMN）和后部网络（PMN）与学习记忆功能密切相关。本课题将采用静息态功能磁共振成像技术和功能连接方法，考察aMCI患者和正常对照的AMN与PMN的动态变化特征。根据2年随访终点aMCI患者是否转化为AD，考察aMCI-AD转化组与aMCI稳定组AMN与PMN功能连接的动态变化差异，及aMCI患者基线AMN与PMN功能连接对其向AD转化的预测价值。本课题有望揭示aMCI向AD转化过程中内颞叶记忆网络变化的神经机制，为AD早期诊断的影像学标志物研究提供新线索。

Amnesic mild cognitive impairment (aMCI) is considered a transitional state between normal aging and Alzheimer’s disease (AD), conferring a 15% annual risk of conversion to probable AD. However, the mechanism of conversion from aMCI to AD remains unclear. Medial temporal lobe is first affected with AD-related neuropathology. The anterior (AMN) and posterior (PMN) medial temporal lobe networks are involved in core domains of learning and memory. In the proposed longitudinal study, we will apply resting functional magnetic resonance imaging (MRI) technique to follow up the patients with aMCI for 2 years. First, we will compare the dynamic change pattern of functional connectivity with AMN and PMN between aMCI patients and normal controls. Per the diagnostic classification of aMCI patients in 2-year follow-up, the aMCI patients will be subgrouped as aMCI-AD converters and aMCI-stable groups. Then, we will examine the different transition of functional connectivity with AMN and PMN between two subgroups. Ultimately, we will explore whether the baseline functional connectivity with AMN and PMN could predict the conversion from aMCI to AD. We anticipate that the findings in the proposed study will reveal the neural mechanism in medial temporal lobe networks implying the conversion from aMCI to AD, and thus, to provide novel clues for identifying neuroimaging markers of AD.