Altered Static and Temporal Dynamic Amplitude of Low-Frequency Fluctuations in the Background Network During Working Memory States in Mild Cognitive Impairment
Altered Static and Temporal Dynamic Amplitude of Low-Frequency Fluctuations in the Background Network During Working Memory States in Mild Cognitive Impairment
复制标题
轻度认知障碍工作记忆状态下背景网络低频波动的静态和时间动态幅度的改变
DOI：
10.3389/fnagi.2019.00152
复制
发表时间：
2019-06-28
影响因子：
4.8
通讯作者：
Li, Juan
中科院分区：
文献类型：
--
作者：
Wang, Pengyun;Li, Rui;Li, Juan
以往对轻度认知障碍(MCI)患者工作记忆表现的研究主要集中在激活改变的神经机制上。到目前为止，很少有研究研究工作记忆状态中背景网络的变化。因此，本研究调查了MCI患者在工作记忆任务过程中背景网络的静态和动态变化。一种混合延迟匹配到样本任务被用来检测MCI患者的工作记忆表现。收集功能磁共振成像(FMRI)数据，以低频波动幅度(ALFF)为标记物，观察背景网络的改变。本研究证实了MCI患者在工作记忆任务中相对于静息状态的ALFF的静态和动态变化。传统的静态分析显示，在工作记忆状态下，正常对照组的右侧前额叶腹外侧皮质(VLPFC)、右侧背外侧PFC(DLPFC)和左侧辅助运动区(NCS)的Alff降低。然而，在MCI患者中，相同的区域显示ALFF增加。此外，与NCS相比，MCI患者表现出与表现相关的功能连接(FC)模式的改变，右侧VLPFC和右侧DLPFC为ROI。在时间动态分析方面，本研究发现在工作记忆状态下，NCS患者双侧丘脑区动态ALFF增加，而MCI患者下降。此外，MCI患者表现出与表现相关的变异系数模式改变；与NCS相比，MCI患者的顶叶和颞叶区域更大，分布更广泛。这是第一次研究处于工作记忆状态的MCI患者背景网络中ALFF的静态和时间动态变化。这一结果扩展了先前的研究，为MCI患者工作记忆缺陷的神经机制提供了一个新的视角。
Previous studies investigating working memory performance in patients with mild cognitive impairment (MCI) have mainly focused on the neural mechanisms of alterations in activation. To date, very few studies have investigated background network alterations in the working memory state. Therefore, the present study investigated the static and temporal dynamic changes in the background network in MCI patients during a working memory task. A hybrid delayed-match-to-sample task was used to examine working memory performance in MCI patients. Functional magnetic resonance imaging (fMRI) data were collected and the marker of amplitude of low-frequency fluctuations (ALFF) was used to investigate alterations in the background network. The present study demonstrated static and dynamic alterations of ALFF in MCI patients during working memory tasks, relative to the resting state. Traditional static analysis revealed that ALFF decreased in the right ventrolateral prefrontal cortex (VLPFC), right dorsolateral PFC (DLPFC), and left supplementary motor area for normal controls (NCs) in the working memory state. However, the same regions showed increased ALFF in MCI patients. Furthermore, relative to NCs, MCI patients demonstrated altered performance-related functional connectivity (FC) patterns, with the right VLPFC and right DLPFC as ROIs. In terms of temporal dynamic analysis, the present study found that in the working memory state dynamic ALFF of bilateral thalamus regions was increased in NCs but decreased in MCI patients. Additionally, MCI patients demonstrated altered performance-related coefficient of variation patterns; the regions in MCI patients were larger and more widely distributed in the parietal and temporal lobes, relative to NCs. This is the first study to examine static and temporal dynamic alterations of ALFF in the background network of MCI patients in working memory states. The results extend previous studies by providing a new perspective on the neural mechanisms of working memory deficits in MCI patients.