Memory Clinic, Department of Neurology, CHU of Liège, Liège, Belgium.
GIGA-Cyclotron Research Centre-IVI, University of Liège, Liège, Belgium.
Hum Brain Mapp. 2019 Dec 15;40(18):5330-5340. doi: 10.1002/hbm.24775. Epub 2019 Aug 24.
Research on the neural correlates of anosognosia in Alzheimer's disease varied according to methods and objectives: they compared different measures, used diverse neuroimaging modalities, explored connectivity between brain networks, addressed the role of specific brain regions or tried to give support to theoretical models of unawareness. We used resting-state fMRI connectivity with two different seed regions and two measures of anosognosia in different patient samples to investigate consistent modifications of default mode subnetworks and we aligned the results with the Cognitive Awareness Model. In a first study, patients and their relatives were presented with the Memory Awareness Rating Scale. Anosognosia was measured as a patient-relative discrepancy score and connectivity was investigated with a parahippocampal seed. In a second study, anosognosia was measured in patients with brain amyloid (taken as a disease biomarker) by comparing self-reported rating with memory performance, and connectivity was examined with a hippocampal seed. In both studies, anosognosia was consistently related to disconnection within the medial temporal subsystem of the default mode network, subserving episodic memory processes. Importantly, scores were also related to disconnection between the medial temporal and both the core subsystem (participating to self-reflection) and the dorsomedial subsystem of the default mode network (the middle temporal gyrus that might subserve a personal database in the second study). We suggest that disparity in connectivity within and between subsystems of the default mode network may reflect impaired functioning of pathways in cognitive models of awareness.
它们比较了不同的测量方法，使用了不同的神经影像学模式，探索了脑网络之间的连接，研究了特定脑区的作用，或试图为认知失认的理论模型提供支持。我们使用静息态 fMRI 连接，以两个不同的种子区域和两种不同的认知失认测量方法，在不同的患者样本中研究默认模式子网络的一致性变化，并将结果与认知意识模型对齐。在第一项研究中，患者及其家属接受了记忆意识评定量表。认知失认症作为患者与家属的差异评分进行测量，并使用海马种子进行连接性研究。在第二项研究中，通过比较自我报告的评分与记忆表现，在脑淀粉样蛋白（作为疾病生物标志物）的患者中测量认知失认症，并使用海马种子进行连接性检查。在这两项研究中，认知失认症都与默认模式网络的内侧颞叶子系统内的连接中断一致，该子系统负责情景记忆过程。重要的是，评分也与内侧颞叶与默认模式网络的核心子系统（参与自我反思）和背内侧子系统（在第二项研究中可能支持个人数据库）之间的连接中断有关。我们认为，默认模式网络的子系统内和子系统之间的连接差异可能反映了意识认知模型中路径功能受损。
