Jiang Yi, Guo Zhiwei, Zhou Xiaobo, Jiang Ning, He Jiayuan
The National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, Sichuan, 610041, China.
The Med-X Center for Manufacturing, Sichuan University, Chengdu, Sichuan, 610041, China.
J Neuroeng Rehabil. 2025 Mar 13;22(1):58. doi: 10.1186/s12984-025-01594-z.
Mild Cognitive Impairment (MCI) is an intermediate stage between the expected cognitive decline of normal aging and Alzheimer's disease (AD). Its management is crucial for it helps intervene and slow the progression of cognitive decline to AD. However, the understanding of the MCI mechanism is not completely clear. As working memory (WM) damage is a common symptom of MCI, this study focused on the core stage of WM, i.e., the memory retrieval stage, to investigate information processing and the causality relationships among brain regions based on electroencephalogram (EEG) signals.
21 MCI and 20 normal cognitive control (NC) participants were recruited. The delayed matching sample paradigm with two different loads was employed to evaluate their WM functions. A time-varying network based on the Adaptive transfer function (ADTF) was constructed on the EEG of the memory retrieval trials.to perform the dynamic brain network analysis.
Our results showed that: (a) Behavioral data analysis: there were significant differences in accuracy and accuracy / reaction time between MCI and NC in tasks with memory load capacity of low load-four and high load-six, especially in tasks with memory load capacity of four. (b) Dynamic brain network analysis: there were significant differences in the dynamic changes of brain network patterns between the two groups during the memory retrieval stage of the WM task. Specifically, in low load WM tasks, the dynamic brain network changes of NC were more regular to accommodate for efficient information processing, with important core nodes showing a transition from bottom to up, while MCI did not display a regular dynamic brain network pattern. Further, the brain functional areas associated with low load WM disorders were mainly located in the left prefrontal lobe (FC1) and right occipital lobe (PO8). Compared with low load WM task, during the high load WM task, the dynamic brain network changes of NC during the memory retrieval stage were regular, and the core nodes exhibited a consistent transition phenomenon from up to bottom to up, which were not observed in MCI.
Behavioral data in the low load WM task paradigm and abnormal electrophysiological signals in the left prefrontal (FC1) and right occipital lobes (PO8) could be used for MCI diagnosis. This is the first time based on large-scale dynamic network methods to investigate the dynamic network patterns of MCI memory retrieval stages under different load WM tasks, providing a new perspective on the neural mechanisms of WM deficits in MCI patients and providing some reference for the clinical intervention treatment of MCI-WM memory disorders.
轻度认知障碍（MCI）是正常衰老所致预期认知衰退与阿尔茨海默病（AD）之间的中间阶段。其管理至关重要，因为它有助于干预并减缓认知衰退向AD的进展。然而，对MCI机制的理解尚不完全清楚。由于工作记忆（WM）损害是MCI的常见症状，本研究聚焦于WM的核心阶段，即记忆检索阶段，基于脑电图（EEG）信号来研究信息处理及脑区之间的因果关系。
招募了21名MCI患者和20名正常认知对照（NC）参与者。采用具有两种不同负荷的延迟匹配样本范式来评估他们的WM功能。在记忆检索试验的EEG上构建基于自适应传递函数（ADTF）的时变网络，以进行动态脑网络分析。
我们的结果显示：（a）行为数据分析：在低负荷-四个和高负荷-六个记忆负荷容量的任务中，MCI与NC在准确性以及准确性/反应时间方面存在显著差异，尤其是在记忆负荷容量为四个的任务中。（b）动态脑网络分析：在WM任务的记忆检索阶段，两组之间脑网络模式的动态变化存在显著差异。具体而言，在低负荷WM任务中，NC的动态脑网络变化更规律，以适应高效的信息处理，重要的核心节点呈现从下到上的转变，而MCI未显示出规律的动态脑网络模式。此外，与低负荷WM障碍相关的脑功能区主要位于左前额叶（FC1）和右枕叶（PO8）。与低负荷WM任务相比，在高负荷WM任务期间，NC在记忆检索阶段的动态脑网络变化是规律的，核心节点呈现从下到上再到上的一致转变现象，而MCI中未观察到这种现象。
低负荷WM任务范式中的行为数据以及左前额叶（FC1）和右枕叶（PO8）的异常电生理信号可用于MCI诊断。这是首次基于大规模动态网络方法研究不同负荷WM任务下MCI记忆检索阶段的动态网络模式，为MCI患者WM缺陷的神经机制提供了新视角，并为MCI-WM记忆障碍的临床干预治疗提供了一些参考。
