Summary

使用功能性磁共振成像连接在颞叶癫痫默认模式网络的网络分析

Published: August 05, 2014
doi:

Summary

在默认模式网络(DMN)在颞叶癫痫(TLE)是在大脑的静息状态下使用基于种子的功能连通性磁共振成像(fcMRI)进行分析。

Abstract

功能性磁共振成像的连接(fcMRI)是一个功能磁共振成像方法,它研究的基础上BOLD信号波动随时间的相关性不同的大脑区域的连通性。颞叶癫痫(TLE)是成人癫痫最常见的类型和涉及多个脑网络。默认模式网络(DMN)参与意识,静息状态下的认知和被认为是受影响颞叶癫痫发作的地方引起意识障碍。使用基于fcMRI种子中癫痫的DMN进行了检查。的DMN的前部和后部轮毂被用作种子在此分析。结果表明在基础状态的前部和颞叶癫痫中的DMN后路集线器之间的连接断开。此外,增加的DMN连接在左侧颞叶癫痫等脑区与右颞叶癫痫下降连通显露。分析表明基于种子的fcMRI如何可以用来探测大脑网络中脑障碍如TLE。

Introduction

功能性磁共振成像连接(fcMRI)是一个相对较新的分析方法,量化的基础上他们的血氧水平依赖(BOLD)的信号时间序列的相似性不同大脑区域之间的关系fMRI数据 – 这就是所谓的“功能性”的连接,并且是从解剖学的连接,它描述的区域( 例如 ,白质纤维)之间的物理连接的存在区分开来。在这种方法中的一种特殊应用,时间序列收集时,参与者不从事一项任务或在所谓的“休息状态”。

虽然在1995年1首次描述,出现了fcMRI导致有关2012年该技术大约1,000出版物兴趣盎然。fcMRI拥有基于任务的功能磁共振成像的内在利益(1)没有要执行特定的任务,( 2)待合作没有必要的,(3)的数据集可以被用来查询几个不同的网络,(4)较好的信噪比存在可能是由于在所涉及的脑能量学的差异,和(5)的规避与任务相关的困惑2。作为一个概念证明,fcMRI改变已被证明与脑电图3和局部场电位在大脑的变化4对应。

fcMRI分析技术包括投资回报率/种子为基础的技术,独立成分分析(ICA),图论分析,Granger因果关系分析,本地方法(低频波动,区域同质化分析的幅度),及其他5。没有任何单一的技术尚未表现出明显优于另一种,但最常用的方法是基于种子和ICA方法6。基于种子的fcMRI从相关研究中的假定网络的预选部分BOLD信号的时间波动称为“种子1;或“感兴趣区域(ROI)”到大脑的其他部分。大脑呈现BOLD信号关联到种子区域的区域被认为是划分所涉及的网络部分。相比之下,ICA使用无模型数据驱动分析通过分析全脑5的血流动力学信号特征提取空间-时间相关的大脑区域(独立组件,集成电路)。

在目前的手稿,在颞叶癫痫中的DMN的静息状态的种子为基础的连通性分析的先前发表的研究使用的方法的描述,提出7。 TLE是成人癫痫的最常见形式。除了 ​​癫痫发作,颞叶癫痫导致多发性脑网络,包括记忆,行为,思想和感觉功能8功能障碍。该DMN由subserving意识,静息状态的认知脑区构成。的DMN已报道涉及具有降低consc关联性发作iousness 9,10。此外,海马是参与TLE该键结构和已被认为是DMN的成分。然而,PCC向海马结构的连通性比与其它DMN的成分,如内侧前额叶和顶叶皮质弱。这表明,海马是DMN的任一个子网或一个相互作用网络11,12。颞叶癫痫和DMN之间的这些共性提出了DMN功能连接被改变在颞叶癫痫的可能性。这种分析的受试者TLE的DMN比较健康对照组,以深入了解DMN在TLE的参与。放置在DMN的主要集线器种子的连接-前部和后部轮毂的区域进行分析12。种子被放置在后部毂组成的retrosplenium /楔前叶(RSP / PCUN)以及前部毂组成的腹内侧前额叶皮质(VMPFC)在具有TLE患者和在健康对照来识别DMN的后部和前部的子网。

Protocol

1。主题 36个学科的研究对象包括三组:右颞叶癫痫(11例),左颞叶癫痫(12例)和健康对照组(n = 13)。所有受试者获得书面知情同意书。该研究遵循美国加州大学洛杉矶分校(UCLA)的机构审查委员会的指导方针。 癫痫学科组应该是病人谁是候选人,前颞叶切除术通过视频脑电图监测,头颅MRI,PET成像和神经心理测试确定。患者应在功能磁共振成像扫描过程中继续他们一贯的药?…

Representative Results

图1显示了DMN显示与连接从后部种子(RSP / PCUN,红-黄色)和前籽(VMPFC,蓝绿色的颜色),并在不同的题目组中发现的网络中进行比较( 图1A-C)的以及彼此之间,即健康对照相比,所有患者的颞叶癫痫( 图1D和1E),然后健康对照组分别相比,左颞叶癫痫( 图1F和1G)和右颞叶癫痫( 图1H和1I)。</stron…

Discussion

癫痫被认为是一个网络的疾病,以及涉及网络的异常是存在癫痫发作过程中,并在间期状态21。基于任务的功能磁共振成像已被用来分析在TLE 8的语言和存储网络的异常。 FcMRI有着先天的优势,在学习DMN 12,因为它是一种网络主要活跃在静止状态。该DMN是大脑区域已经被认为是活跃在谁是静置并从事自发的思绪清醒的个人网络。这些区域被示出为包括在VMPFC,Rsp时/ PCUN,后?…

Divulgazioni

The authors have nothing to disclose.

Acknowledgements

NIH-NINDS K23格兰特NS044936(JMS),资助这项研究是由美国癫痫基金会,医学计算和综合生物医学研究中心(CIBR)种子奖助金(ZH)贝勒医学院提供的; ,并在莱夫家庭基金会(JMS) 数据采集提供了协助:伊丽莎白·皮尔斯(加州大学洛杉矶分校)。

Materials

MRI machine
Linux workstation with image analysis software installed

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Haneef, Z., Lenartowicz, A., Yeh, H. J., Engel Jr., J., Stern, J. M. Network Analysis of the Default Mode Network Using Functional Connectivity MRI in Temporal Lobe Epilepsy. J. Vis. Exp. (90), e51442, doi:10.3791/51442 (2014).

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