Krajcovicova Lenka, Mikl Michal, Marecek Radek, Rektorova Irena
First Department of Neurology, School of Medicine, Masaryk University, Brno, Czech Republic Applied Neuroscience Research Group, CEITEC - Central European Institute of Technology, Masaryk University, Brno, Czech Republic.
Multimodal and Functional Imaging Research Group, CEITEC - Central European Institute of Technology, Masaryk University, Brno, Czech Republic.
J Alzheimers Dis. 2014;41(4):1229-38. doi: 10.3233/JAD-131208.
Changes in connectivity of the posterior node of the default mode network (DMN) were studied when switching from baseline to a cognitive task using functional magnetic resonance imaging. In all, 15 patients with mild to moderate Alzheimer's disease (AD) and 18 age-, gender-, and education-matched healthy controls (HC) participated in the study. Psychophysiological interactions analysis was used to assess the specific alterations in the DMN connectivity (deactivation-based) due to psychological effects from the complex visual scene encoding task. In HC, we observed task-induced connectivity decreases between the posterior cingulate and middle temporal and occipital visual cortices. These findings imply successful involvement of the ventral visual pathway during the visual processing in our HC cohort. In AD, involvement of the areas engaged in the ventral visual pathway was observed only in a small volume of the right middle temporal gyrus. Additional connectivity changes (decreases) in AD were present between the posterior cingulate and superior temporal gyrus when switching from baseline to task condition. These changes are probably related to both disturbed visual processing and the DMN connectivity in AD and reflect deficits and compensatory mechanisms within the large scale brain networks in this patient population. Studying the DMN connectivity using psychophysiological interactions analysis may provide a sensitive tool for exploring early changes in AD and their dynamics during the disease progression.
利用功能磁共振成像技术，研究了从基线状态切换到认知任务时默认模式网络（DMN）后节点的连接性变化。共有15名轻度至中度阿尔茨海默病（AD）患者和18名年龄、性别及教育程度相匹配的健康对照者（HC）参与了该研究。采用心理生理交互作用分析来评估由于复杂视觉场景编码任务的心理效应导致的DMN连接性（基于去激活）的特定改变。在健康对照者中，我们观察到后扣带回与颞中回及枕叶视觉皮层之间任务诱导的连接性降低。这些发现表明在我们的健康对照者队列的视觉处理过程中腹侧视觉通路成功参与。在AD患者中，仅在右侧颞中回的一小部分区域观察到参与腹侧视觉通路的区域有激活。从基线状态切换到任务状态时，AD患者的后扣带回与颞上回之间还存在额外的连接性变化（降低）。这些变化可能与AD患者视觉处理和DMN连接性紊乱均有关，反映了该患者群体大规模脑网络内的缺陷和代偿机制。使用心理生理交互作用分析研究DMN连接性可能为探索AD的早期变化及其在疾病进展过程中的动态变化提供一个敏感的工具。
