原发性失眠局部脑区功能变化的静息态功能磁共振成像研究

目的探讨原发性失眠(PI)患者静息状态下全脑范围内局部脑功能磁共振成像特点。方法对59例PI患者及47例年龄、性别和受教育程度均与之匹配的健康对照者进行静息态功能磁共振成像扫描。应用局部一致性分析方法,得出PI患者局部一致性(Re Ho)异常的脑区。结果与正常对照组相比,在静息状态下PI患者左侧脑岛、右侧前扣带回、双侧中央前回、左侧楔叶局部一致性升高;而在右侧扣带中回、左侧梭状回局部一致性降低。结论静息状态下PI患者存在情绪、感觉运动区域等多个脑区的局部功能活动的异常,从功能分化的角度探究PI患者大脑神经活动的改变,有利于进一步理解PI的神经活动特点。     

静息态默认功能网络磁共振成像研究

大脑处于无任务的静息状态时,仍存在着某种功能活动,表明大脑在静息状态时存在有组织的网络.扣带回后部皮层、楔前叶、前额叶内侧皮层构成静息态默认功能网络.本文就这方面的研究进展作一综述.     

基于fMRI功能连接度分析正常人相关脑区在运动过程中的参与程度

目的 在运动及静息两种状态下,观察初级运动区(M1)与其他运动相关区域之间功能连接程度,分析特定功能区在运动执行过程中的作用.方法 选取6名正常人作为研究对象,进行血氧水平依赖功能磁共振成像(BOLD-fMRI)检查.功能成像分为静息功能、右手运动功能、左手运动功能三部分.运动功能采用Block设计,采取手指顺序对指任务.扫描结果 采用统计参数图 (SPM2)进行数据分析和脑功能区定位.功能连接度采用时间相关算法,选取运动任务时对应的最强激活点(均为一侧M1区)作为种子点,分别在静息功能数据和运动功能数据中将该种子区与相应全脑做相关分析,计算不同脑区与种子区之间的相关性,以Z值反映其功能连接程度,并观察同一脑区在运动及静息两种状态下与种子点之间Z值的变化.结果 在静息状态下,与种子点相关联的区域为双侧躯体感觉运动区(SMC)、辅助运动区(SMA)及同侧顶上小叶(SPL);在运动状态下,与种子点相关联的区域为双侧SMC、SMA、同侧SPL及小脑前叶(ALC);在运动状态下双侧SMC及SMA之间功能联系的Z值较静息状态下普遍增大.结论 静息状态下双侧SMC、SMA及同侧SPL之间存在比较稳定的功能联系;运动状态下双侧SMC及SMA之间功能联系增强.运动肢体同侧ALC参与运动任务的执行,但不参与静息状态下运动区之间的功能连接.     

基于语言双流模型的卒中后失语右脑功能网络研究

目的探究右脑功能网络在左侧脑损伤卒中后失语(PSA)的效应特点。方法2018年12月至2019年6月,招募左脑半球损伤PSA患者12例(患者组)和匹配的健康成年人12例(对照组),以双流语言模型为参照,应用静息态功能磁共振观察右脑功能网络特征。结果2例患者脱落。与对照组相比,在语言背侧通路中,患者组缘上回至额中回、三角部额下回功能连接增强,中央后回至岛盖部额下回功能连接降低;在语言腹侧通路中,角回至眶部额下回功能连接增强;在腹、背侧双通路模型中,语言功能皮质至皮质下核团功能连接增强,额、颞叶和边缘系统功能连接减弱。三角部额下回至豆状壳核功能连接增强与复述能力呈负相关(r=-0.720,P<0.05),岛盖部额下回至尾状核功能连接增强与说和复述能力呈负相关关系(r<-0.696,P<0.05)。患者组右脑语言关键脑区局部网络指标和全局指标均与对照组有显著性差异(|t|>2.143,P<0.05)。结论PSA患者右脑功能网络在脑卒中后发生功能重组,语言关键皮质与皮质下核团功能连接增强可能是右脑代偿的关键环节。     

静息状态脑功能连接磁共振成像的分析方法及应用

多数功能磁共振成像(fMRI)研究是在特定的实验任务条件下对大脑的活动进行分析.然而,大脑在静息状态下仍存在自发神经元活动,这些自发活动具有较强的低频同步性,对于静息状态下的大脑活动的研究有利于全面认识大脑的内在活动机制.本文主要综述目前静息状态脑功能连接fMRI常用分析方法及其在临床疾病中的初步应用.     

基于静息态网络神经精神类疾病的脑机制研究进展

大脑是人体至关重要的组成部分,其不同功能区域相互协调、相互作用共同执行人类的各种简单、复杂活动。现代科学研究证明人脑在静息状态下即存在多种脑功能网络,静息态功能磁共振成像技术的日臻成熟为脑功能网络研究带来契机,现已被广泛应用于神经精神类疾病的脑机制研究中,为神经精神类疾病的诊治及评估提供了崭新的方法与思路。本文着重对基于静息态网络的脑机制研究方法及其在神经精神类疾病中的应用进行阐述。     

轻微型肝性脑病患者静息状态下脑缺省模式网络

目的 利用静息功能磁共振成像(fMRI)观察轻微型肝性脑病(MHE)患者脑缺省模式网络的改变. 方法对14例MHE患者和14名正常对照者行静息状态下的功能磁共振扫描,利用独立成分分析方法,分离得到各自的脑缺省模式网络脑区,各组进行单样本t检验组内分析和两样本t检验组间分析,观察MHE患者静息状态下脑缺省模式网络的改变. 结果 MHE患者和正常对照组均显示出典型的静息态脑缺省模式网络空间分布模式.但与正常对照组相比,MHE患者大部分脑缺省模式网络脑区功能连接降低,包括:左侧后扣带回、双侧前扣带回、双侧额中回、左侧海马旁回;而右侧楔前叶的功能连接较正常对照组升高. 结论静息状态下,MHE患者大部分脑缺省模式网络脑区功能连接度下降,而楔前叶增加,反映了MHE患者的大脑内源性功能组织发生损伤.静息fMRI可用于观察MHE患者脑缺省模式网络的改变.     

创伤后应激障碍患者静息态下脑功能局部一致性的研究

目的利用局部一致性(ReHo)方法探测创伤后应激障碍(PTSD)患者在静息状态下是否存在着大脑功能异常。方法 2010年5月-7月对18例未经治疗的地震PTSD患者和19例同样经历地震但未患PTSD的对照者进行了静息态功能磁共振成像(Rs-fMRI)扫描。应用ReHo方法处理Rs-fMRI数据,得出PTSD患者的异常脑区,并将患者存在组间差异的脑区ReHo值与临床用PTSD诊断量表(CAPS)、汉密尔顿抑郁量表(HAMD)和汉密尔顿焦虑量表(HAMA)分别进行相关分析。结果①PTSD组ReHo显著增加的脑区包括右侧颞下回、楔前叶、顶下叶、中扣带回,左侧枕中回以及左/右侧后扣带回;ReHo显著降低的脑区包括左侧海马和左/右侧腹侧前扣带回。②异常脑区中后扣带回和右侧中扣带回ReHo与HAMD呈负相关(中扣带回r=0.575,P=0.012;右侧后扣带回:r=0.507,P=0.032),其余脑区ReHo与临床指标无明显相关性(P>0.05),左侧海马与CAPS的相关性相对其他脑区较大(r=0.430,P=0.075)。结论 PTSD患者在静息状态下即存在着局部脑功能活动的降低和增加,ReHo方法可能有助于研究PTSD患者静息状态脑活动。     

首发抑郁症脑局部一致性静息态MRI对比研究

目的利用静息态功能磁共振成像(resting-state functional MRI,rf MRI)技术,探索抑郁症患者异常脑功能活动区域及抑郁心境对患者脑功能的影响。材料与方法对30例抑郁症患者[符合DSM-IV抑郁症的诊断标准,汉密尔顿抑郁量表(HAMD-17)评分≥17分]和30例健康志愿者行rf MRI扫描。使用局部一致性(regional homogeneity,Re Ho)方法对比分析Re Ho在抑郁症组与正常对照组之间的不同。结果抑郁症组与正常对照Re Ho图组间分析:抑郁症组大脑的双侧部分额、颞、顶叶、双侧壳核、右侧尾状核、杏仁核、扣带回、小脑蚓部等脑区的Re Ho显著高于正常对照组,而在双侧前额叶、楔前叶、舌回及小脑半球等脑区Re Ho显著减低(P0.001,K10)。结论 Re Ho方法可检出抑郁心境造成的局部脑组织BOLD信号同步性的改变,更客观地反映全脑的功能状态,有助于抑郁症的基础和临床研究。     

个体前额叶与丘脑之间的功能连接与其对网游渴求程度的关系:一项静息态fMRI研究

目的 通过功能磁共振成像技术,探究网游成瘾组与健康对照组在静息状态下功能连接的差异,并探寻该功能连接和个体对网游渴求程度的关系.材料与方法 根据网游应用情况调查问卷、网游成瘾诊断量表共招募网游成瘾组被试32名,健康对照组被试33名.所有被试均填写网游渴求度量表并在静息状态下进行磁共振扫描,获取在静息状态下的脑数据.选取...     

Interindividual variability in the hemispheric organization for speech

A PET activation study was designed to investigate hemispheric specialization during speech comprehension and production in right- and left-handed subjects. Normalized regional cerebral blood flow (NrCBF) was repeatedly monitored while subjects either listened to factual stories (Story) or covertly generated verbs semantically related to heard nouns (Gener), using silent resting (Rest) as a common control condition. NrCBF variations in each task, as compared to Rest, as well as functional asymmetry indices (FAI = right minus left NrCBF variations), were computed in anatomical regions of interest (AROIs) defined on the single-subject MNI template. FAIs were predominantly leftward in all regions during both tasks, although larger FAIs were observed during Gener. Subjects were declared "typical" for language hemispheric specialization based on the presence of significant leftward asymmetries (FAI < 0) in the pars triangularis and opercularis of the inferior frontal gyrus during Gener, and in the middle and inferior temporal AROIs during Story. Six subjects (including five LH) showed an atypical language representation. Among them, one presented a right hemisphere specialization during both tasks, another a shift in hemispheric specialization from production to comprehension (left during Gener, right during Story). The group of 14 typical subjects showed significant positive correlation between homologous left and right AROIs NrCBF variations in temporal areas during Story, and in temporal and inferior frontal areas during Gener, almost all regions presenting a leftward FAI. Such correlations were also present in deactivated areas with strong leftward asymmetry (supramarginalis gyrus, inferior parietal region). These results suggest that entry into a language task translates into a hemispheric reconfiguration of lateral cortical areas with global NrCBF increase in the dominant hemisphere and decrease in the minor hemisphere. This can be considered as the setting up of a "language mode", under the control of a mechanism that operates at a perisylvian level. On top of this global organization, regional variations carry on the performance of the cognitive operations specific to the language task to be performed. Hemispheric relationships could be different in atypical subjects, with either between task hemispheric regulation differences or differences in regional specialization.     

汉字词语语音、语义处理相关脑区的功能磁共振研究

目的探索汉字词语处理的脑偏侧化;研究汉字词语的语音、语义处理相关脑区及小脑在汉字词语处理中的作用.方法对13例健康、右利手、母语为汉语的受试者,采用功能磁共振成像技术,模块设计的刺激模式,运用视觉呈现方法,每名受试者参加两组实验:动词产生组及假词默读组.结果动词产生组及假词默读组均显著激活左侧额下回、左侧额中回、左侧额上回、左侧顶上小叶、双侧枕叶以及双侧小脑半球,在两组中均以左侧大脑半球激活为著;Wernicke区在两组均未见激活;左侧IFG在动词产生组较假词默读组激活范围广泛;双侧扣带回、左侧颞下回、右侧额中回、左侧丘脑及右侧尾状核仅在动词产生组被激活.结论左侧大脑半球是汉字词语处理的优势半球;Broca区在汉字词语处理中既有语音又有语义处理方面的作用;双侧小脑参与汉字词语的语音处理;大脑皮层下的一些核团可能参与汉字词语的语义处理.     

维吾尔语和汉语动词产生相关脑区的功能性磁共振成像研究

目的通过功能性磁共振成像（fMRI）观察母语为维吾尔语（简称维语）和汉语正常人执行动词产生任务时的脑激活区及其脑激活差异区,探讨语言理解和产生的神经机制,以及脑损伤后语言障碍及其康复机制。 方法以维语和汉语名词为基本实验材料,通过血氧水平依赖功能性磁共振成像（BOLD-fMRI）扫描31例维吾尔族（语组）和28例汉族（汉语组）正常志愿者执行动词产生任务时的脑激活区,采集fMRI数据,并进行组内及组间比较。 结果汉语组的主要脑激活区为左侧尾状核、左侧枕下回、左侧梭状回、双侧辅助运动区（BA8/6区）、左侧BA32区、左侧楔前叶、左侧顶上、下小叶（BA7区）、左侧角回、右侧中央前回（BA9区）、左侧三角部额下回、右侧岛盖部额下回和双侧小脑。维语组的主要脑激活区为左侧中央前回（BA9区）、左侧岛盖部额下回、左侧三角部额下回和左侧小脑。维语组和汉语组组间比较发现,汉语组在左侧尾状核体、左侧眶部额中回、右侧尾状核头和双侧扣带回前部（BA32区）有明显激活,与维语组比较,差异有统计学意义（P<0.05）;而维语组未见比汉语组更明显激活的脑区。 结论维语和汉语正常人动词产生激活脑区不完全相同;维语文字的加工处理主要集中在左侧大脑半球;汉字加工处理比维语文字加工处理需要更多右侧大脑半球的参与。     

Hemispheric asymmetry in cognitive division of anterior cingulate cortex: A resting-state functional connectivity study

The cognitive division of anterior cingulate cortex (ACC-cd) plays an important role in cognitive control via a distributed attention network. The structural hemispheric asymmetries of ACC have been revealed by several neuroimaging studies. However potential functional hemispheric asymmetries of ACC remain less clear. Investigating the functional hemispheric asymmetries of ACC helps for a better understanding of ACC function. The aim of this study was to use resting-state functional magnetic resonance imaging (fMRI) to examine hemispheric differences in the functional networks associated with ACC-cd in the two hemispheres. ROI-based functional connectivity analysis was performed on a group of 49 right-handed healthy volunteers. The left and right ACC-cd showed significant differences in their patterns of connectivity with a variety of brain regions, including the dorsolateral prefrontal cortex, inferior parietal lobule, superior parietal lobule and dorsal posterior cingulate cortex in their ipsilateral cerebral cortex, as well as cerebellar tonsil and inferior semilunar lobule in their contralateral cerebellar hemisphere. Specifically, for these areas, we found significantly greater connectivity strength with ACC-cd in the right hemisphere than the left, regardless of whether the connection was positive or negative. The current results highlight the presence of clear asymmetries in functional networks associated with ACC-cd. Future functional imaging studies are needed to give greater attention to the lateralized ACC functional networks which are observed.     

From novel to familiar: tuning the brain for metaphors

Metaphors are fundamental to creative thought and expression. Newly coined metaphors regularly infiltrate our collective vocabulary and gradually become familiar, but it is unclear how this shift from novel to conventionalized meaning happens in the brain. We investigated the neural career of metaphors in a functional magnetic resonance imaging study using extensively normed new metaphors and simulated the ordinary, gradual experience of metaphor conventionalization by manipulating participants' exposure to these metaphors. Results showed that the conventionalization of novel metaphors specifically tunes activity within bilateral inferior prefrontal cortex, left posterior middle temporal gyrus, and right postero-lateral occipital cortex. These results support theoretical accounts attributing a role for the right hemisphere in processing novel, low salience figurative meanings, but also show that conventionalization of metaphoric meaning is a bilaterally-mediated process. Metaphor conventionalization entails a decreased neural load within semantic networks rather than a hemispheric or regional shift across brain areas.     

刺激健康青年太溪穴和假穴的功能磁共振研究

目的：应用功能磁共振（fMRI）观察针刺太溪穴和假穴后脑激活区的反应。方法：选取健康青年志愿者12例,采用组块模式即静息阶段与刺激阶段交替出现针刺太溪穴及假穴,均匀提插捻转,角度180°,频率90次／min,反复3次。针刺期被试者头部固定,进行fMRI扫描。结果：12例被试者太溪穴（SPM2软件组分析,corrected,0.05,K≥10）主要激活右侧颞上回BA22,左侧额中回BA46,其次为左右顶叶的中央后回BA2、BA3,左额叶的额下回BA45和左顶叶的顶下小叶BA40;假穴则没被激活。结论：太溪穴与假穴的激活是不同的,与经脉相关的经络、脏腑与脑激活联系密切相关。     

Cerebral regions and hemispheric specialization for processing spatial frequencies during natural scene recognition. An event-related fMRI study

It has been suggested that visual scene recognition is mainly based on spatial frequency (Fourier) analysis of the image. This analysis starts with processing low spatial frequencies (LSF), followed by processing high spatial frequencies (HSF). Within the framework of the spatial frequency analysis, the right/left hemisphere would be predominantly involved in LSF/HSF analysis, respectively. The aim of this event-related fMRI study was to evaluate neural correlates and hemispheric specialization of spatial frequency analysis during recognition of nonfiltered (NF) and filtered, either in LSF or HSF, natural scenes. Comparing LSF or NF to HSF scene recognition, significant activation was obtained within right anterior temporal cortex and right parahippocampal gyrus. As these regions are known to be involved in scene processing, we interpret this result as suggesting that scene recognition is mainly based on LSF extraction and analysis. When LSF scene was compared to HSF scene recognition, supplementary activation was obtained within the right inferior parietal lobule that likely reflects attentional modulation on spatial frequency processing. A direct interhemispheric comparison for each particular band of spatial frequencies highlighted predominance within the early visual areas (such as the middle occipital gyrus) to the right for LSF processing and to the left for HSF processing. This result provides supplementary evidence for hemispheric specialization at early levels of visual analysis when spatial frequencies are processed.     

Gender difference analysis of cortical thickness in healthy young adults with surface-based methods

We have examined gender differences of cortical thickness using a 3-D surface-based method that enables more accurate measurement in deep sulci and localized regional mapping compared to volumetric analyses. Cortical thickness was measured using a direct method for calculating the distance between corresponding vertices from inner and outer cortical surfaces. We normalized cortical surfaces using 2-D surface registration and performed diffusion smoothing to reduce the variability of folding patterns and to increase the power of the statistical analysis. In stereotaxic space, significant localized cortical thickening in women was found extensively in frontal, parietal and occipital lobes, including the superior frontal gyrus (SFG), superior parietal gyrus (SPG), inferior frontal gyrus (IFG) and postcentral gyrus (PoCG) in the left hemisphere and mostly in the parietal lobe, including the SPG in the right hemisphere. In the temporal lobe, small regions of the left and right caudal superior temporal gyrus (STG) and the left temporal pole showed significantly greater cortical thickness in women. The temporal lobe shows relatively less significant thickening than other lobes in both hemispheres. In native space, significantly greater cortical thickness in women was detected in left parietal region, including SPG and PoCG. No significant local increases of cortical thickness were observed in men in both spaces. These findings suggest statistically significant cortical thickening in women in localized anatomical regions, which is consistent with several previous studies and may support a hypothesis of sexual dimorphism.     

White matter integrity in right hemisphere predicts pitch-related grammar learning

White matter plays an important role in various domains of cognitive function. While disruptions in white matter are known to affect many domains of behavior and cognition, the ability to acquire grammatical regularities has been mostly linked to the left hemisphere, perhaps due to its dependence on linguistic stimuli. The role of white matter in the right hemisphere in grammar acquisition is yet unknown. Here we show for the first time that in the domain of pitch, intact white matter connectivity in right-hemisphere analogs of language areas is important for grammar learning. A pitch-based artificial grammar learning task was conducted on subjects who also underwent diffusion tensor imaging. Probabilistic tractography using seed regions of interest in the right inferior frontal gyrus and right middle temporal gyrus showed positive correlations between tract volume and learning performance. Furthermore, significant correlations were observed between learning performance and FA in white matter underlying the supramarginal gyrus, corresponding to the right temporal-parietal junction of the arcuate fasciculus. The control task of recognition did not correlate with tract volume or FA, and control tracts in the left hemisphere did not correlate with behavioral performance. Results show that the right ventral arcuate fasciculus is important in pitch-based artificial grammar learning, and that brain structures subserving learning may be tied to the hemisphere that processes the stimulus more generally.