在严峻的老龄化背景下，阿尔茨海默病（AD）对老年健康形成了巨大的威胁。由于目前仍缺乏AD晚期的有效治疗手段，早期预警和干预变得尤为重要。主观认知减退（SCD）是AD最早出现的临床症状之一，可能是AD干预介入的最早时期。但目前相关研究中普遍采用的有意记忆范式，存在对SCD日常记忆模式模拟不足的问题，阻碍了对SCD成因及神经机制的深入认识。为了解决这一问题，本项目拟使用无意记忆任务范式，通过功能磁共振成像技术，从功能激活、功能连接和功能网络三个神经影像层面：1）揭示无意记忆范式在SCD识别中的优势；2）确定无意记忆范式中记忆编码加工深度对SCD识别的影响；3）刻画SCD在记忆编码及再认阶段的独特神经活动模式；4）建立SCD筛选和评估的综合模型。预期本项目能够从全新的角度，深入理解SCD的产生机制及神经基础，从而丰富和完善AD的发展理论，为AD的早期评估和干预提供支持。

As it is known to all, alzheimer’s disease (AD) has posed a great threat to the health of the elderly. Lacking in effective treatment for AD in the late stage makes early detection and intervention become particularly important. Subjective cognitive decline (SCD) is one of the earliest clinical symptoms of AD and may be an appropriate stage for AD intervention. However, the intentional memory paradigm that current used in relevant researches is not sufficient to simulate the daily memory process of people with SCD, resulting in difficulties in understanding of the neurocognitive mechanism of SCD. To address this issues, the current project recruits an incidental memory paradigm and compare functional activation, functional connectivity and functional network during incidental memory processing among healthy elderly, people with SCD, and mild cognitive impairment (MCI) via functional magnetic resonance imaging. . We hope to obtain the following achievements: 1) To reveal the advantage of incidental memory paradigm in discriminating SCD from healthy elderly and MCI; 2) To estimate the influence of memory coding processing depth in this paradigm on the identification of SCD; 3) To describe the unique neural activity pattern of SCD in the stage of memory coding and recognition; 4) To form a comprehensive model for SCD screening and evaluation. This project will deepen our understanding of the causes and neural mechanisms of SCD from a new perspective and improve the development theory of AD as well as provide support for the early assessment and intervention of AD.