Exploring Functional Connectivity of Gray Matter Heterotopia Using fMRI

目的 通过观察灰质异位脑功能连接区的空间分布形式,探索灰质异位与正常脑区间的神经功能联系.方法 研究对象为8例确诊为双侧灰质异位癫痫患者,经Siemens 3.0 T磁共振仪采集静息态及3D结构像数据.以异位灰质团块作为种子点,进行基于相关的全脑功能连接分析,并对异位灰质功能连接网络存在的模式进行观察分析.结果 (1)一侧异位灰质与对侧异位灰质存在正相关功能连接;(2)异位灰质与双侧基底神经节存在正相关连接.(3)异位灰质与正常大脑皮层存在正相关功能连接,但其空间模式与异位灰质所处的部位有关.(4)异位灰质与双侧大脑皮层也存在负相关功能连接区域,但其空间模式无明显一致性.结论 灰质异位不是孤立的异常脑结构,其不但与对侧的异位灰质保持功能连接,还与众多大脑皮层区保持着广泛的功能连接,这可能由于异位灰质团与正常皮层具有相同起源以及相似发育过程而形成的.其与基底神经节存在功能连接可能是异位灰质经常引发癫痫发作的病理生理基础之一.     

阻塞性睡眠呼吸暂停综合征患者静息态下海马功能连接的fMRI研究

目的 采用种子点功能连接方法,分析阻塞性睡眠呼吸暂停综合征(OSAS)患者静息态下海马与全脑功能连接的改变,探索OSAS患者认知功能下降的神经生理机制.方法 40例OSAS患者及40例正常对照组(NC)进行静息态下脑功能磁共振成像(fMRI)数据采集.以左、右侧海马为种子点进行全脑的功能连接,采用两样本t检验比较组间功能连接差异.结果 与NC组比较,OSAS患者左侧海马与双侧楔前叶、额中回、前扣带回、中央前回及右侧后扣带回功能连接减低,而与双侧小脑后叶功能连接增高.OSAS患者右侧海马与双侧额中回、后扣带回、边缘叶及右侧楔前叶功能连接减低,而与左侧顶下小叶及右侧小脑后叶功能连接增高.结论 OSAS患者海马与多个脑区存在功能连接异常,可能是OSAS患者认知功能下降的神经机制.     

皮质下血管性认知功能障碍的脑默认网络静息态功能磁共振研究

目的运用静息态功能磁共振成像(rs-fMRI)研究皮质下缺血性血管性认知功能障碍(VCI-SIVD)患者在静息状态下的脑默认网络(DMN)。方法收集缺血性脑小血管疾病患者68例,经临床痴呆量表评分后分为血管性痴呆组(VaD组)12例,非痴呆型血管性认知功能障碍组(VCIND组)21例,认知功能正常者35例为对照组,分别采集高分辨率结构像和静息态功能磁共振数据,通过独立成分分析方法(ICA)计算并对比3组患者脑功能活动的改变。采用两样本t检验分别对VCIND组与正常对照组、VaD组与VCIND组、VaD组与正常对照组DMN的功能连接进行组间比较,观察静息状态下脑默认网络的改变情况,并分析VaD患者DMN默认网络与认知功能间的相关性。结果与正常对照组相比,VCIND组患者默认网络脑区的功能连接既有增高也有降低,增高的脑区包括双侧顶叶及颞中回,降低的脑区包括眶额叶、内侧前额叶、前扣带回及双侧枕叶;VaD组患者出现双侧小脑的功能连接增强,VaD组眶额叶、额中回、额下回、双侧枕叶及双侧颞叶的功能连接减低;VaD患者DMN统计脑图与数字连线A、数字符号转换、MOCA等多个临床量表评分存在显著相关性,差异有统计学意义(P0.05)。结论在静息状态下,血管性认知功能障碍患者的大脑默认模式网络存在异常,并存在以执行功能障碍为主的多个领域的认知功能损害,其认知功能障碍可能与额叶-皮质下环路受损有关。独立成分分析在评价血管性认知功能障碍及其早期诊断中有重要价值。     

HIV感染者认知功能正常时静息态脑功能连接的研究

【摘要】目的：探讨认知功能正常时HIV感染者与正常人的静息态脑功能连接情况。方法：按照入选标准搜集25例HIV感染者和27例健康志愿者作为正常对照组,比较蒙特利尔认知评估量表评分、年龄、性别、教育水平的差异。应用静息态脑功能技术以双侧大脑各区为种子点,分析两组各种子点与全脑功能连接的差异,体素P取0.005,团簇P取0.05。结果：HIV感染组与正常对照组各种子点均有统计学差异,经多重校正后有19个种子点8个脑区差异具有统计学意义。HIV感染组在以左侧额极内侧、双侧海马、双侧前扣带回、左侧顶叶、左侧丘脑、左侧梭状回的种子点与全脑的功能连接高于正常组;HIV感染组在以双侧视觉皮层枕叶、左侧岛叶区域的种子点与全脑的功能连接低于正常组;HIV感染组在以右侧运动皮层、左侧顶下叶的种子点与全脑的功能连接与正常组比较既有升高又有降低。结论：HIV感染者认知功能正常时的静息态脑功能连接与正常人有显著差异,提示HIV感染者在认知功能正常时脑功能连接可能已经出现异常,HIV病毒可能影响脑功能的连接。     

脑电功能磁共振同步联合对发作间期颞叶癫痫的研究

目的 研究伴有双侧海马硬化颞叶癫痫患者的脑功能活动.资料与方法 7例颞叶癫痫患者,均为双侧海马硬化,其中男6例,女1例,平均年龄16.7岁.单纯部分性发作者4例、部分继发全面发作者3例.7例患者均接受了脑电功能磁共振同步联合检查.结果 5例患者内侧颞叶有明显激活,2例颞叶激活区位于新皮层中;边缘系统和皮层下结构有较明显的激活;大脑皮层中的激活区主要位于中央区.组分析结果显示,负激活的脑区与经典的脑缺省模式脑区一致.结论内侧颞叶硬化与颞叶癫痫之间关系紧密,边缘系统和皮层下结构参与痫样放电的易化和传播,长期的异常放电会对癫痫患者的脑功能活动产生影响.     

基于低频振荡幅度算法的脑电功能磁共振同步成像技术对颞叶癫痫的研究

目的 采用静息功能磁共振成像低频振幅技术,通过观察双侧海马硬化(HS)颞叶癫痫(TLE)患者脑血氧水平依赖(BOLD)信号活动的改变,探讨TLE脑活动的神经机制.资料与方法 采用低频振幅算法,对9例双侧HS的TLE患者及9名正常志愿者静息功能磁共振成像数据进行对比分析,观察TLE患者发作间期痫样放电时(IED)振荡幅度增高及降低的区域.结果 TLE患者伴发IED时BOLD信号振荡幅度改变的区域基本呈双侧对称分布.振幅增加的区域包括:双侧海马、杏仁核、扣带回等边缘系统,双侧中央运动区、颞叶皮层,丘脑及中脑结构.振荡幅度降低的区域包括:扣带回前部(ACC)、内侧前额叶(MPFC)及顶下小叶(IPC)等经典缺省模式区域,而后扣带回(PCC)和楔前叶(Pcu)则未包含其中.结论 低频振幅功能磁共振成像技术可以对癫痫引起脑的活动改变情况进行观察.振幅增高的脑区反映大脑对癫痫活动的产生、传播等易化作用,振幅降低区域反映了特定脑区功能的抑制,尤其是缺省模式功能的受抑制.这些改变反映了大脑易化与抑制两个系统对癫痫的脑功能进行调节.     

灰质异位的功能磁共振成像研究(附3例报告)

目的:对灰质异位进行运动功能的功能磁共振成像研究,探讨异位灰质的神经生理功能及功能磁共振成像在神经外科中的作用。方法:采用功能磁共振成像技术对3例拟行手术治疗的灰质异位且伴癫痫症状的患者进行对指运动任务下的脑区反应观察。结果:2例顶叶灰质异位患者在对侧手指运动时异位灰质内出现明显的反应信号,否定外科手术治疗计划。1例额叶的灰质异位患者异位灰质内未出现反应。结论:异位的灰质可以具有运动中枢功能,对于靠近主要功能中枢的灰质异位患者在手术计划的拟定时要考虑异位灰质是否具有功能。功能磁共振成像可以用于评价灰质异位的神经生理,有助于治疗方法的选择。     

基底神经节的认知和记忆功能研究进展

经过神经解剖学、神经生物化学和细胞生理学等领域长时间研究的积累 ,有关基底神经节的功能研究终于开始浮出水面。虽然目前对基底神经节到底具有或参与多少或什么样的功能尚无一致看法 ,但近年的研究表明基底神经节不仅调节和控制运动 ,同时还具有或参与多项其它功能 ,如感觉反馈、模式转换 (ｓｅｔ ｓｈｉｆｔｉｎｇ)、视知觉等 ;新近研究进一步发现基底神经节与大脑新皮层有着广泛神经联结 ,可能具有或参与更高级、更复杂的认知功能 ,如决策、注意选择、行为变换 (ｂｅｈａｖｉｏｒａｌｓｈｉｆｔ)、时间认知、启动效应、工作记忆和言语…     

基于动态因果模型研究小脑在癫痫发作间期痫样放电中的作用

目的 采用脑电功能磁共振同步联合成像(electroencephalogram-functional MRI,EEG-fMRI)方法,观察癫痫发作间期痫样放电时脑活动情况,探讨小脑在痫样放电中的作用及神经机制.资料与方法 10例复杂部分性发作癫痫患者,行EEG-fMRI,以发作间期痫样放电的相关设计模式对功能磁共振成像(fMRI)数据进行分析,对比观察痫样放电引起的大脑皮层及小脑活动情况,采用动态因果模型(dynamic causal modelling,DCM),观察两者之间功能连接和因果关系.结果 发作间期痫样放电时,在大脑皮层广泛激活的基础上,小脑半球的代谢活动也明显增强,其中8例小脑的最大激活点位于小脑半球皮层,2例位于小脑蚓部.皮层与小脑之间存在可靠的双向功能连接.结论 发作间期痫样放电时,大脑皮层中的癫痫灶通过皮层下的神经核团与小脑之间形成往返神经环路;小脑在癫痫的发放和传播中起重要的调节作用.     

脑皮质发育畸形的功能MRI研究

目的 探讨脑皮质发育畸形(MCD)并癫痫患者的脑运动及语言功能区激活情况,及其与异常灰质的关系.方法 选取7例不同类型的MCD患者(局灶性皮质发育不良2例、灰质异位2例、脑裂畸形2例、以及多小脑回畸形1例),应用3TMR仪分别进行双侧肢体对指运动、足趾运动、以及动词联想、图片命名任务的BOLD fMRI扫描,采用组块设计方案,利用SPM 5软件的总体线性模型(GLM)进行分析,产生激活数据.将激活阈值(P＜0.001,经校正检验,激活范围≥30个体素)以上数据按照运动及语言任务不同对激活脑区进行归类分析,并分别观察MCD异常灰质与相应功能区的关系.结果 运动任务激活范围及强度以感觉运动皮层、运动前区为主.语言任务中动词联想任务激活范围以语言相关脑区及运动前区为主,激活强度以语言区为主,且Wernicke区激活强度较高.图片命名任务激活范围及强度均以视皮层为主,但在语言相关皮层激活上,强度及范围以Broca区稍著.两种语言任务联合应用语言皮层区激活范围、强度占据较显著优势.MCD患者功能激活皮层区包含发育异常结构,激活范围均可以包括或延伸到畸形区域.6例行手术治疗患者术后临床随访均未出现新的神经功能损伤及认知障碍,并且癫痫发作频率有显著下降.结论 MCD大脑皮层具有运动、语言功能,相应部位的异常灰质均可能参与简单或复杂任务脑功能活动,在外科术前应得到客观正确的功能评估以避免并发症发生.     

Disrupted small world networks in patients without overt hepatic encephalopathy: A resting state fMRI study

Purpose

To explore changes in functional connectivity and topological organization of brain functional networks in cirrhotic patients with minimal hepatic encephalopathy (MHE) and non hepatic encephalopathy (nonHE) and their relationship with clinical markers.

Materials and methods

Resting-state functional MR imaging was acquired in 22 MHE, 29 nonHE patients and 33 healthy controls. Functional connectivity networks were obtained by computing temporal correlations between any pairs of 90 cortical and subcortical regions. Graph analysis measures were quantitatively assessed for each subject. One-way analysis of covariance was applied to identify statistical differences of functional connectivity and network parameters among three groups. Correlations between clinical markers, such as Child–Pugh scores, venous blood ammonia level, and number connection test type A (NCT-A)/digit symbol test (DST) scores, and connectivity/graph metrics were calculated.

Results

Thirty functional connectivities represented by edges were found to be abnormal (P < 0.05, FDR corrected) in cirrhotic patients, in which 16 edges (53.3%) were related with sub-cortical regions. MHE patients showed abnormal small-world attributes in the functional connectivity networks. Cirrhotic patients had significantly reduced nodal degree in 8 cortical regions and increased nodal centrality in 3 cortical regions. Twenty edges were correlated with either NCT-A or DST scores, in which 13 edges were related with sub-cortical regions. No correlation was found between Child–Pugh scores and graph theoretical measures in cirrhotic patients.

Conclusion

Disturbances of brain functional connectivity and small world property loss are associated with neurocognitive impairment of cirrhotic patients. Reorganization of brain network occurred during disease progression from nonHE to MHE.     

肝性脑病患者基于静息态fMRI的全脑功能连接研究

目的：采用静息态功能磁共振成像研究肝性脑病患者全脑功能网络连接改变机制。方法：采集13例慢性肝硬化肝性脑病患者和17例健康志愿者的静息态血氧依赖水平功能磁共振成像（BOLD-fMRI）数据,采用自动化解剖标记（AAL）模板计算90个脑区的两两间功能连接情况。结果：肝性脑病患者有15条功能连接出现异常,其中12条功能连接显著下降（P〈0．01）,3条显著升高（P〈0．01）,且其中9条异常连接出现在皮层下区域与皮层区域之间,且改变的功能连接与神经心理学测试存在一定相关性。结论：肝性脑病患者的基底节一丘脑一皮层回路受损,功能连接的改变与肝性脑病患者认知功能的改变有关。     

Role of the corpus callosum in functional connectivity

BACKGROUND AND PURPOSE: Regional cerebral blood flow fluctuates synchronously in corresponding brain regions between the hemispheres. This synchrony implies neuronal connections between brain regions. The synchrony of blood flow changes is defined operationally as functional connectivity. Our purpose was to measure functional connectivity in patients with corpus callosal agenesis, in whom the interhemispheric connectivity is hypothetically diminished. METHODS: In three patients with agenesis of the corpus callosum, functional MR imaging was performed while patients performed text-listening and finger-tapping tasks. Functional images were also acquired while the patients performed no specific task (resting state). Regions of activation temporally correlated with the performance of the tasks were identified by cross-correlating the task data with a reference function. Voxel clusters (seed voxels) that corresponded to regions of activation in the task-activation data set were selected in the resting data set. All the voxels in the resting 3D data set that had a correlation coefficient exceeding 0.4 were identified. The number of these voxels in the ipsilateral and contralateral hemispheres was tabulated. RESULTS: In all patients, technically adequate functional MR and functional connectivity MR maps were obtained. For both tasks, activation was found in both hemispheres. For all of the seed voxels, significantly more functionally connected voxels were found in the ipsilateral hemisphere than in the contralateral hemisphere. For most seed voxels, no functionally connected voxels were found in the contralateral hemisphere. CONCLUSION: Interhemispheric functional connectivity in the motor and auditory cortices is diminished in patients with agenesis of the corpus callosum compared with that of healthy subjects.     

Metabolic connectivity by interregional correlation analysis using statistical parametric mapping (SPM) and FDG brain PET; methodological development and patterns of metabolic connectivity in adults

Purpose  Regionally connected areas of the resting brain can be detected by fluorodeoxyglucose-positron emission tomography (FDG-PET). Voxel-wise metabolic connectivity was examined, and normative data were established by performing interregional correlation analysis on statistical parametric mapping of FDG-PET data. Materials and methods  Characteristics of seed volumes of interest (VOIs) as functional brain units were represented by their locations, sizes, and the independent methods of their determination. Seed brain areas were identified as population-based gyral VOIs (n = 70) or as population-based cytoarchitectonic Brodmann areas (BA; n = 28). FDG uptakes in these areas were used as independent variables in a general linear model to search for voxels correlated with average seed VOI counts. Positive correlations were searched in entire brain areas. Results  In normal adults, one third of gyral VOIs yielded correlations that were confined to themselves, but in the others, correlated voxels extended to adjacent areas and/or contralateral homologous regions. In tens of these latter areas with extensive connectivity, correlated voxels were found across midline, and asymmetry was observed in the patterns of connectivity of left and right homologous seed VOIs. Most of the available BAs yielded correlations reaching contralateral homologous regions and/or neighboring areas. Extents of metabolic connectivity were not found to be related to seed VOI size or to the methods used to define seed VOIs. Conclusions  These findings indicate that patterns of metabolic connectivity of functional brain units depend on their regional locations. We propose that interregional correlation analysis of FDG-PET data offers a means of examining voxel-wise regional metabolic connectivity of the resting human brain. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Cerebral interregional correlations of associative language processing: a positron emission tomography activation study using fluorine-18 fluorodeoxyglucose

Even though there have been numerous positron emission tomography (PET) activation studies on the perfusional and metabolic bases of language processing, little is known about the intracerebral functional network of language and cognitive processes. It was the aim of this study to investigate the cerebral interregional correlations during voluntary word association versus word repetition in healthy subjects to gain insight into the functional connectivity of associative speech processing. Due to individual variability in functional anatomy, the study protocol was designed as an averaged single-subject study. Eight healthy volunteers performed a verbal association task during fluorine-18 fluorodeoxyglucose (¹⁸F-FDG) PET scanning. Two different tasks were performed in randomized order: (a) word repetition (after auditory presentation of nouns) as a control condition, and (b) word association (after auditory presentation of nouns) as a specific semantic activation. The regional metabolic rate of glucose (rMRGlu) was calculated after brain regionalization [112 regions of interest on individual 3D flash magnetic resonance imaging (MRI)] and PET/MRI realignment. Statistical analysis was performed for comparison of association and repetition and for calculation of interregional correlation coefficients during both tasks. Compared with word repetition, word association was associated with significant increases in rMRGlu in the left prefrontal cortex, the left frontal operculum (Broca’s area) and the left insula, indicating involvement of these areas in associative language processing. Decreased rMRGlu was found in the left posterior cingulum during word association. During word repetition, highly significant negative correlations were found between the left prefrontal cortex, the contralateral cortex areas and the ipsilateral posterior cingulum. These negative correlations were almost completely eliminated during the association task, suggesting a functional decoupling of the strict intercorrelation pattern. Received 16 March and in revised form 9 July 1998     

Effect of focal and nonfocal cerebral lesions on functional connectivity studied with MR imaging

BACKGROUND AND PURPOSE: Functional connectivity MR (fcMR) imaging is used to map regions of brain with synchronous, regional, slow fluctuations in cerebral blood flow. We tested the hypothesis that focal cerebral lesions do not eradicate expected functional connectivity. METHODS: Functional MR (fMR) and fcMR maps were acquired for 12 patients with focal cerebral tumors, cysts, arteriovenous malformations, or in one case, agenesis of the corpus callosum. Task activation secondary to text listening, finger tapping, and word generation was mapped by use of fMR imaging. Functional connectivity was measured by selecting "seed" voxels in brain regions showing activation (based on the fMR data) and cross correlating with every other voxel (based on data acquired while the subject performed no task). Concurrence of the fMR and fcMR maps was measured by comparing the location and number of voxels selected by both methods. RESULTS: Technically adequate fMR and fcMR maps were obtained for all patients. In patients with focal lesions, the fMR and fcMR maps correlated closely. The fcMR map generated for the patient with agenesis of the corpus callosum failed to reveal functional connectivity between blood flow in the left and right sensorimotor cortices and in the frontal lobe language regions. Nonetheless, synchrony between blood flow in the auditory cortices was preserved. On average, there was 40% concurrence between all fMR and fcMR maps. CONCLUSION: Patterns of functional connectivity remain intact in patients with focal cerebral lesions. Disruption of major neuronal networks, such as agenesis of the corpus callosum, may diminish the normal functional connectivity patterns. Therefore, functional connectivity in such patients cannot be fully demonstrated with fcMR imaging.     

Altered Activity and Functional Connectivity of Superior Temporal Gyri in Anxiety Disorders: A Functional Magnetic Resonance Imaging Study

Objective

The prior functional MRI studies have demonstrated significantly abnormal activity in the bilateral superior temporal gyrus (STG) of anxiety patients. The purpose of the current investigation was to determine whether the abnormal activity in these regions was related to a loss of functional connectivity between these regions.

Materials and Methods

Ten healthy controls and 10 anxiety patients underwent noninvasive fMRI while actively listening to emotionally neutral words alternated by silence (Task 1) or threat-related words (Task 2). The participants were instructed to silently make a judgment of each word''s valence (i.e., unpleasant, pleasant, or neutral). A coherence analysis was applied to the functional MRI data to examine the functional connectivity between the left and the right STG, which was selected as the primary region of interest on the basis of our prior results.

Results

The data demonstrated that the anxiety patients exhibited significantly increased activation in the bilateral STG than the normal controls. The functional connectivity analysis indicated that the patient group showed significantly decreased degree of connectivity between the bilateral STG during processing Task 2 compared to Task 1 (t = 2.588, p = 0.029). In addition, a significantly decreased connectivity was also observed in the patient group compared to the control group during processing Task 2 (t = 2.810, p = 0.012).

Conclusion

Anxiety patients may exhibit increased activity of the STG but decreased functional connectivity between the left and right STG, which may reflect the underlying neural abnormality of anxiety disorder, and this will provide new insights into this disease.     

脑梗死患者手运动功能区fMRI研究

目的 对不同时期脑梗死所致偏瘫患者采用主动手运动任务模式进行功能磁共振成像(functional magnetic resonance imaging,fMRI),研究运动功能区损伤及恢复特点,以指导临床康复治疗.资料与方法 脑梗死所致偏瘫患者40例.累及基底节区25例,皮层区15例.其中急性期15例,亚急性期9例,慢性期16例.采用组块设计进行单手拇指与余4指同步对指运动,所有患者均进行健侧和患侧手的主动运动实验.采用SPM 99软件进行预处理和统计分析.结果 (1)急性期梗死灶累及皮层区组,健侧半球初级感觉运动区(SMC)激活强度及范围明显大于患侧半球.皮层区组患侧半球SMC激活强度及范围均小于基底节区组;(2)梗死灶累及基底节区组,健侧与患侧半球SMC激活强度及范围于急性期与慢性期间差异无统计学意义;(3)病例的纵向观察:患肢功能恢复较好的患者,患侧和(或)健侧半球SMC的激活强度和(或)范围有不同程度增强,同时激活脑区增多,均可见小脑半球的激活;患肢功能恢复较差的患者,患侧半球SMC的激活强度及范围逐渐减小直至消失.结论 (1)fMRI能准确地判定脑梗死患者脑功能区的损伤程度及有无重组的脑功能区;(2)皮层区梗死患者运动功能受损较为严重,SMC起关键作用,其受累程度直接影响运动功能损伤的等级及恢复程度;(3)脑梗死偏瘫患者在运动功能康复治疗过程中,病变周围及远隔部位可出现功能和结构变化,提示存在脑功能区重组.     

Functional connectivity in the thalamus and hippocampus studied with functional MR imaging

BACKGROUND AND PURPOSE: With functional connectivity functional MR imaging, co-variance in signal intensity has been shown in functionally related regions of brain in participants instructed to perform no cognitive task. These changes are thought to represent synchronous fluctuations in blood flow, which imply neuronal connections between the regions. The purpose of this study was to map functional connectivity in subcortical nuclei with functional connectivity functional MR imaging. METHODS: Imaging data were acquired with an echo-planar sequence from six volunteers who performed no specific cognitive task. For functional connectivity functional MR imaging, a "seed" voxel or group of voxels was selected from the resting data set in the thalamus or in the hippocampus. Control voxels in gray matter presumed not to be eloquent cortex were also chosen. The correlation coefficient of the seed voxels and the control voxels with every other voxel in the resting data set was calculated. The voxels with correlation coefficients greater than or equal to 0.5 were mapped onto anatomic images for the functional connectivity functional MR images. The anatomic location of these voxels was determined by conventional parcellation methods. RESULTS: For each participant, functional connectivity functional MR imaging maps based on four seed voxels in the thalamus or hippocampus showed clusters of voxels in the ipsilateral and contralateral thalamus or hippocampus. For control voxels, few voxels in the hippocampus or thalamus showed significant correlation. Significantly more pixels in the ipsilateral hippocampus correlated with the seed voxel than in the contralateral hippocampus. The differences between numbers of functionally connected voxels in ipsilateral thalamus and those in contralateral thalamus were not significant. CONCLUSIONS: The thalamus and hippocampus show functional connectivity, presumably representing synchronous changes in blood flow.     

Functional connectivity of motor cortical network in patients with brachial plexus avulsion injury after contralateral cervical nerve transfer: a resting-state fMRI study

Introduction

The purpose of this study is to assess the functional connectivity of the motor cortical network in patients with brachial plexus avulsion injury (BPAI) after contralateral C7 nerve transfer, using resting-state functional magnetic resonance imaging (RS-fMRI).

Methods

Twelve patients with total brachial plexus root avulsion underwent RS-fMRI after contralateral C7 nerve transfer. Seventeen healthy volunteers were also included in this fMRI study as controls. The hand motor seed regions were defined as region of interests in the bilateral hemispheres. The seed-based functional connectivity was calculated in all the subjects. Differences in functional connectivity of the motor cortical network between patients and healthy controls were compared.

Results

The inter-hemispheric functional connectivity of the M1 areas was increased in patients with BPAI compared with the controls. The inter-hemispheric functional connectivity between the supplementary motor areas was reduced bilaterally.

Conclusions

The resting-state inter-hemispheric functional connectivity of the bilateral M1 areas is altered in patients after contralateral C7 nerve transfer, suggesting a functional reorganization of cerebral cortex.