The effects of hippocampal lesions on MRI measures of structural and functional connectivity.-猫眼课题宝

DOI：

10.1002/hipo.22621

发表时间：

2016-11

期刊：

HIPPOCAMPUS

影响因子：

3.5

通讯作者：

中科院分区：

医学3区

文献类型：

作者：

Henson, Richard N.;Greve, Andrea;Cooper, Elisa;Gregori, Mariella;Simons, Jon S.;Geerligs, Linda;Erzinclioglu, Sharon;Kapur, Narinder;Browne, Georgina

关键词：

hippocampus amnesia diaschisis functional connectivity structural connectivity VBM DTI

来源链接：

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5082505/?report=classic

局灶性病变可以影响远端脑区之间的连接（连接性神经联系不能），并影响主要脑网络的图论性质（连接性神经联系不能）。由于其独特的解剖结构和多种功能，海马体被认为是大脑网络的关键“枢纽”。我们研究了海马病变对6例健忘症患者的结构和功能连接的影响，使用了一系列的磁共振成像（MRI）分析。神经心理学评估显示明显的情景记忆障碍和其他认知领域的整体表现完好。海马体是唯一表现出灰质体积减少的脑结构，这在患者中是一致的，穹窿是唯一根据两种扩散指标显示结构连接改变的主要白色物质束。尽管如此，功能性MRI显示功能性连接的增加和减少。在默认模式网络内的区域水平上的分析显示功能连接减少，包括非海马区域之间的连接（连接不能）。功能网络水平的分析显示，丘脑和楔前叶网络之间的连接减少，但默认模式网络和额叶执行网络之间的连接增加。整体功能性连接体显示出患者功能分离增加的证据（连接体神经联系不能）。总之，这些结果表明海马损伤后的动态重组，涉及边缘间脑结构和更大规模网络的功能连接减少和增加。© 2016 The Authors Hippocampus由Wiley Periodicals，Inc.

Focal lesions can affect connectivity between distal brain regions (connectional diaschisis) and impact the graph‐theoretic properties of major brain networks (connectomic diaschisis). Given its unique anatomy and diverse range of functions, the hippocampus has been claimed to be a critical “hub” in brain networks. We investigated the effects of hippocampal lesions on structural and functional connectivity in six patients with amnesia, using a range of magnetic resonance imaging (MRI) analyses. Neuropsychological assessment revealed marked episodic memory impairment and generally intact performance across other cognitive domains. The hippocampus was the only brain structure exhibiting reduced grey‐matter volume that was consistent across patients, and the fornix was the only major white‐matter tract to show altered structural connectivity according to both diffusion metrics. Nonetheless, functional MRI revealed both increases and decreases in functional connectivity. Analysis at the level of regions within the default‐mode network revealed reduced functional connectivity, including between nonhippocampal regions (connectional diaschisis). Analysis at the level of functional networks revealed reduced connectivity between thalamic and precuneus networks, but increased connectivity between the default‐mode network and frontal executive network. The overall functional connectome showed evidence of increased functional segregation in patients (connectomic diaschisis). Together, these results point to dynamic reorganization following hippocampal lesions, with both decreased and increased functional connectivity involving limbic‐diencephalic structures and larger‐scale networks. © 2016 The Authors Hippocampus Published by Wiley Periodicals, Inc.