联合运用VBM方法和DTI技术揭示精神分裂症的神经元基质

目的:运用基于体素形态学VBM(voxel-based morphometry)方法探索未用药的首发精神分裂症患者与正常人脑结构差异,并用弥散张量成像DTI(diffusion tensor imaging)技术观察脑白质结构完整性。方法:纳入18个首发精神分裂症患者,和19个年龄性别都相符的正常人,分别采集高分辨T1WI图像和DTI图像。T1WI图像的处理采用优化的VBM方法进行全脑分析比较。结果:与健康对照组相比,首发精神分裂症患者双侧枕叶和双侧丘脑明显的灰质密度降低,左侧顶枕束、左上纵束及右扣带回后部白质密度降低。而右枕额纤维束,右胼胝体压部到右扣带回后部有相应FA值降低。结论:联合优化的VBM以及DTI图像分析技术,发现首发精神分裂症患者枕叶视辐射区,丘脑皮质回路(边缘系统)皮质以及白质完整性受损,提示在精神分裂症早期就存在边缘系统和视觉通路的神经发育异常。     

采用基于纤维束示踪的空间统计分析方法观察先天性耳聋患者的脑白质改变

目的 应用基于纤维束示踪的空间统计分析(TBSS)方法,观察先天性感音神经性耳聋患者听觉中枢及相关中枢的脑白质改变.方法 对15例先天性耳聋患者和28名正常志愿者的听觉中枢及相关中枢进行扩散张量成像(DTI)及三维快速扰相梯度回波数据采集.应用TBSS对先天性耳聋患者和正常志愿者的DTI数据进行分析,获取部分各向异性(FA)值具有显著性差异的脑区.结果 与正常志愿者相比,先天性耳聋患者的双侧额下回、颞横回、颞上回、颞中回中后部内侧的脑白质以及双侧内囊前肢、外囊、视辐射FA值显著下降(P<0.05),左侧颞中回中后部内侧脑白质及视辐射FA值下降的范围大于右侧.结论 先天性耳聋患者听觉中枢及相关中枢脑白质FA值显著下降,提示出入听觉中枢及相关中枢的脑白质纤维髓鞘形成不良和(或)白质纤维数量减少.     

重度颅脑创伤后认知功能障碍患者蒙特利尔认知评估量表评分与扩散张量成像的相关性研究

目的研究重度颅脑创伤（TBI）后认知障碍患者蒙特利尔认知评估量表（MoCA）评分与扩散张量成像（DTI）的相关性。 方法选择重度TBI恢复期男性患者8例作为研究对象,所有患者均采用MoCA评分评定其记忆、注意、语言、执行等各项功能,同时采用DTI测量感兴趣区（放射冠、上纵束、下纵束、内囊、胼胝体膝部、胼胝体体部、胼胝体压部和扣带回）白质纤维束的各异向性（FA）值,最后采用Pearson软件分析MoCA评分与感兴趣区FA值的相关性。 结果胼胝体体部、胼胝体膝部和上纵束的FA值与MoCA评分均具有相关性,r值分别为r=0.746,P<0.05;r=0.689,P<0.05;r=0.748,P<0.05。 结论重度颅脑创伤患者的胼胝体体部、胼胝体膝部、上纵束白质纤维束损伤与认知障碍显著的相关性。     

扩散张量成像在颅内占位性病变中的应用研究

目的:评价MRI扩散张量成像在颅内占位性病变中的应用价值。材料与方法:经手术及病理证实的星形细胞瘤、脑膜瘤、垂体瘤、转移瘤及脑脓肿共46例。行常规MRI扫描、扩散张量成像(DTI)检查。构建各向异性分数(FA)图,并测量病变及周围白质的FA值。结果:正常白质纤维在FA图上表现为高信号。肿瘤多呈低信号。在肿瘤存在时,周围白质纤维可表现为受推压移位或浸润破坏,破坏后FA值降低,表现为低信号。脓肿多呈低信号,其内部若有尚未破坏的白质纤维存在,可呈高信号。这些表现在常规MRI图像上均未清楚显示。结论:DTI可清楚显示占位性病变与周围白质纤维的解剖关系,指导临床制定手术方案。     

采用基于纤维束示踪的空间统计分析方法观察阿尔茨海默病患者的脑白质改变

目的:采用基于纤维束空间统计分析(TBSS)法观察阿尔茨海默病(Alzheimer's disease,AD)患者弥散张量改变,以研究其全脑白质纤维束损害的特点。方法:选取24例AD患者和21例非神经系统疾病患者(对照者),对全脑进行DTI序列扫描。采用FSL软件内的TBSS软件包,对被试的DTI扫描数据进行预处理后,对AD患者及对照者的部分各向异性分数(FA)、图像进行基于体素的全脑非参数统计学比较。结果:与对照者相比,AD患者FA值明显减低的脑区包括穹窿和双侧额上回、额中回、左侧额下回白质束及双侧颞中回、右侧颞上回、左侧颞下回、左侧楔叶、右侧扣带束前部、胼胝体膝部、左侧扣带束后部、左侧海马白质束、右侧海马旁回白质束,而双侧丘脑及中脑皮质脊髓束FA值显著降低(P<0.05)。结论:采用TBSS分析方法具有相对客观性,本研究提示AD患者存在明显的白质束损伤,且范围累及较广,对了解AD脑白质异常的潜在神经生物学机制有重要价值。     

白质纤维束成像在颅脑疾病中的初步临床应用研究

目的 评价白质纤维束成像在颅脑疾病中的临床应用价值。方法 11例志愿者、15例缺血性脑卒中患者、3例胶质母细胞瘤及2例脑膜瘤患者行扩散张量成像。应用日本东京大学的dTV软件观察白质纤维束形态；对锥体束和胼胝体进行三维显示。结果 全部志愿者和患者均可清楚地观察白质纤维束形态。15例缺血性脑卒中患者可观察到锥体束不同程度的中断，5例脑肿瘤患者可以观察到锥体束和胼胝体受压、移位。结论 本研究表明，使用扩散张量-白质纤维束成像，可以在活体内清楚、立体地观察锥体束和胼胝体等白质纤维束形态变化以及与颅内病灶之间的关系。     

基于磁共振扩散张量成像的急性脑梗死白质纤维束损伤研究

目的:探讨磁共振(MR)扩散张量成像(DTI)评估急性脑梗死白质纤维束损伤的价值以及与神经功能的相关性。方法:回顾性分析2014年7月至2016年1月在我院就诊的39例幕上单侧急性脑梗死患者的临床和MR资料。在DTI序列各项异性指数(FA)和平均弥散系数(MD)参数图上选取梗死病灶及对侧为感兴趣区(ROI),并以ROI为种子点拟合扩散张量纤维束成像(DTT)图。比较梗死病灶与对侧ROI的FA和MD值改变。计算梗死侧/对侧的参数相对值(rFA和rMD),分析两者与患者入院神经功能的相关性。入院神经功能以美国国立卫生研究院卒中量表(NIHSS)评定。结果:DTT显示梗死病灶区白质纤维束损伤。梗死病灶FA和MD值均明显低于对侧(均P0.05)。rMD值与入院NIHSS评分呈明显负相关(r=-0.540, P=0.001)。结论:基于DTI可有效评估急性脑梗死白质纤维束损伤,并且rMD值与患者入院神经功能具有明显负相关,为急性脑梗死患者的临床诊治提供参考。     

扩散张量成像评价颈总动脉交感神经网剥脱术治疗儿童脑瘫的价值

目的应用磁共振扩散张量成像(diffusion tensor imaging,DTI)及扩散张量纤维束成像(diffusion tensor tracking,DTT),探讨其对脑瘫患儿颈总动脉交感神经网剥脱术后脑白质恢复的评估价值。材料与方法对30例痉挛型单侧脑瘫患儿手术前、后进行临床评估和常规MRI、DTI检查,测量并比较术前术侧和对侧、术前和术后双侧内囊后肢及大脑脚的各向异性分数(fractional anisotropy,FA)值,并对白质纤维束进行三维重建。运用粗大运动功能分级系统(gross motor function classification system,GMFCS)评价患儿运动功能。采用配对样本t检验比较术前术侧和对侧、术前和术后脑白质不同部位FA值的差异,以Spearman相关分析不同白质纤维束DTI参量与GMFCS的相关性。结果术前术侧不同部位白质纤维束FA值均显著低于对侧,差异有统计学意义(P0.01)。术后6个月脑瘫患儿术侧不同部位白质纤维束FA值与术前相比显著增加(P0.01),粗大运动功能获得改善。术后6个月患儿对侧不同部位白质纤维束FA值与术前相比差异无统计学意义(P0.05)。患儿临床GMFCS与FA值呈负相关(P0.01),且与内囊后肢、大脑脚的相关性都较高(r=-0.933,P0.01;r=-0.873,P0.01)。结论 DTI联合DTT可用于定量评价脑瘫患儿术后脑白质的恢复情况,对辅助临床治疗和预后评估具有重要作用。     

精神分裂症患者的扩散张量成像与认知功能相关性研究

目的：了解精神分裂症（SCZ）患者的脑白质损害的特点及其与临床症状、认知功能损害之间的关 系。方法：招募精神分裂症患者（SCZ 组）及健康对照（HC 组）各 30 例,对 2 组进行磁共振扩散张量成像 （DTI）扫描,及临床症状评定、SCZ认知功能简明评测量表（BACS）测评;采用优化的空间统计方法（TBSS） 对DTI数据进行分析,分析两组之间DTI扫描结果的差异及其与临床症状、BACS得分的相关性。结果： SCZ 组全脑多处纤维束 FA 值低于对照组（P＜0.05）;左侧小脑上脚 FA 值与符号编码得分呈正相关（r= 0.384,P=0.039）。结论：SCZ患者存在全脑多处白质纤维损害,且部分重要白质纤维损害与认知障碍存在 相关性。     

酒精依赖者脑白质微结构多参数扩散张量成像:基于纤维束示踪的空间分析

目的运用扩散张量成像技术(DTI)及基于纤维束示踪空间统计分析(TBSS)方法研究酒依赖患者脑白质微结构的改变。方法对30例酒精依赖者(患者组)和30例健康志愿者(对照组)进行全脑DTI数据采集。通过TBSS方法比较两组间各向异性分数(FA)、平均扩散系数(MD)、轴向扩散系数(AD)和径向扩散系数(RD)的差异。对患者组差异区域的FA值与蒙特利尔认知评估量表(MoCA)评分及嗜酒年限进行Pearson相关性分析。结果与正常对照组比较:患者组胼胝体膝部、体部及压部、右侧钩状束、右侧上纵束、右侧下纵束、右侧下额枕束、两侧丘脑前辐射及两侧穹窿/终纹体FA值减低(P0.05,FWE校正);胼胝体体部、右侧钩状束、右侧上纵束、两侧丘脑前辐射及两侧穹窿/终纹体束MD值增加(P0.05,FWE校正);胼胝体膝部、体部及压部、右侧上纵束、右侧下额枕束、两侧扣带束、两侧丘脑前辐射、两侧穹窿/终纹体束及两侧钩状束RD值增加(P0.05,FWE校正);两组AD值比较差异无统计学意义(P0.05,FWE校正);全脑FA均值与嗜酒年限呈负相关(r=-0.464);胼胝体压部FA值与视空间和执行功能正相关(r=0.391)。结论酒依赖患者存在广泛的脑白质纤维微结构改变及认知功能障碍,白质纤维以脱髓鞘改变为主,脑白质结构损害随其酒精依赖时间而持续进展。     

基于弥散张量成像的终末期肾病脑白质结构异常与认知功能障碍相关性分析

目的 探讨终末期肾病（ESRD）患者脑白质结构异常与认知损伤的相关性。方法 对26例ESRD患者（ESRD组）和25名健康志愿者（HC组）进行蒙特利尔认知量表（MoCA）评估,并比较两组受试者整体认知评分和子项评分的差异;采用基于DTI的纤维束骨架的空间统计分析（TBSS）方法获得各向异性分数（FA）、平均扩散系数（MD）、轴向扩散系数（AD）及平行扩散系数（RD）;将ESRD组MoCA得分与有差异脑区FA值进行基于体素的Spearman相关分析。结果 ESRD组与HC组比较,MoCA总分和MoCA子项包括视觉空间与执行能力、语言和延迟回忆差异有统计学意义（P均<0.05）;ESRD组双侧下额枕束、辐射冠、上纵束、穹窿、丘脑后辐射、大脑脚,右侧内囊及外囊,脑桥,胼胝体膝部和体部FA值减低（P均<0.05）;ESRD组双侧大脑白质对称MD、AD、RD升高（P均<0.05）。ESRD组右侧外囊FA值与MOCA得分呈正相关（r=0.61,P<0.05）。结论 终末期肾病存在包括记忆、执行力等领域认知损伤,且与脑白质纤维束异常存在一定相关性;右侧外囊区的FA值减低与认知损伤密切相关,可为ESRD患者在血液透析过程中脑结构-功能损伤研究提供新的诊断学标记。     

DTI and MTR abnormalities in schizophrenia: analysis of white matter integrity

Diffusion tensor imaging (DTI) studies in schizophrenia demonstrate lower anisotropic diffusion within white matter due either to loss of coherence of white matter fiber tracts, to changes in the number and/or density of interconnecting fiber tracts, or to changes in myelination, although methodology as well as localization of such changes differ between studies. The aim of this study is to localize and to specify further DTI abnormalities in schizophrenia by combining DTI with magnetization transfer imaging (MTI), a technique sensitive to myelin and axonal alterations in order to increase specificity of DTI findings. 21 chronic schizophrenics and 26 controls were scanned using Line-Scan-Diffusion-Imaging and T1-weighted techniques with and without a saturation pulse (MT). Diffusion information was used to normalize co-registered maps of fractional anisotropy (FA) and magnetization transfer ratio (MTR) to a study-specific template, using the multi-channel daemon algorithm, designed specifically to deal with multidirectional tensor information. Diffusion anisotropy was decreased in schizophrenia in the following brain regions: the fornix, the corpus callosum, bilaterally in the cingulum bundle, bilaterally in the superior occipito-frontal fasciculus, bilaterally in the internal capsule, in the right inferior occipito-frontal fasciculus and the left arcuate fasciculus. MTR maps demonstrated changes in the corpus callosum, fornix, right internal capsule, and the superior occipito-frontal fasciculus bilaterally; however, no changes were noted in the anterior cingulum bundle, the left internal capsule, the arcuate fasciculus, or inferior occipito-frontal fasciculus. In addition, the right posterior cingulum bundle showed MTR but not FA changes in schizophrenia. These findings suggest that, while some of the diffusion abnormalities in schizophrenia are likely due to abnormal coherence, or organization of the fiber tracts, some of these abnormalities may, in fact, be attributed to or coincide with myelin/axonal disruption.     

White Matter Involvement in Chronic Musculoskeletal Pain

There is emerging evidence that chronic musculoskeletal pain is associated with anatomic and functional abnormalities in gray matter. However, little research has investigated the relationship between chronic musculoskeletal pain and white matter. In this study, we used whole-brain tract-based spatial statistics and region-of-interest analyses of diffusion tensor imaging data to demonstrate that patients with chronic musculoskeletal pain exhibit several abnormal metrics of white matter integrity compared with healthy controls. Chronic musculoskeletal pain was associated with lower fractional anisotropy in the splenium of the corpus callosum and the left cingulum adjacent to the hippocampus. Patients also had higher radial diffusivity in the splenium, right anterior and posterior limbs of the internal capsule, external capsule, superior longitudinal fasciculus, and cerebral peduncle. Patterns of axial diffusivity (AD) varied: patients exhibited lower AD in the left cingulum adjacent to the hippocampus and higher AD in the anterior limbs of the internal capsule and in the right cerebral peduncle. Several correlations between diffusion metrics and clinical variables were also significant at a P < .01 level: fractional anisotropy in the left uncinate fasciculus correlated positively with total pain experience and typical levels of pain severity. AD in the left anterior limb of the internal capsule and left uncinate fasciculus was correlated with total pain experience and typical pain level. Positive correlations were also found between AD in the right uncinate and both total pain experience and pain catastrophizing. These results demonstrate that white matter abnormalities play a role in chronic musculoskeletal pain as a cause, a predisposing factor, a consequence, or a compensatory adaptation.PerspectivePatients with chronic musculoskeletal pain exhibit altered metrics of diffusion in the brain's white matter compared with healthy volunteers, and some of these differences are directly related to symptom severity.     

White matter tracts in first-episode psychosis: a DTI tractography study of the uncinate fasciculus

A model of disconnectivity involving abnormalities in the cortex and connecting white matter pathways may explain the symptoms and cognitive abnormalities of schizophrenia. Recently, diffusion imaging tractography has made it possible to study white matter pathways in detail, and we present here a study of patients with first-episode psychosis using this technique. We studied the uncinate fasciculus (UF), the largest white matter tract that connects the frontal and temporal lobes, two brain regions significantly implicated in schizophrenia. Nineteen patients with first-episode schizophrenia and 23 controls were studied using a probabilistic tractography algorithm (PICo). Fractional anisotropy (FA) and probability of connection were obtained for every voxel in the tract, and the group means and distributions of these variables were compared. The spread of the FA distribution in the upper tail, as measured by the squared coefficient of variance (SCV), was reduced in the left UF in the patient group, indicating that the number of voxels with high FA values was reduced in the core of the tract and suggesting the presence of changes in fibre alignment and tract coherence in the patient group. The SCV of FA was lower in females across both groups and there was no correlation between the SCV of FA and clinical ratings.     

Combined analyses of thalamic volume, shape and white matter integrity in first-episode schizophrenia

The thalamus has been considered to be integral to the pathophysiology of schizophrenia. To determine whether its anatomical abnormalities may be associated with cognitive deficits in the onset of schizophrenia, we assessed thalamic volume, shape, white matter integrity, and their correlations with cognition in patients with first-episode schizophrenia. T1-weighted magnetic resonance and diffusion tensor (DT) images were collected in 49 healthy comparison controls (CON) and 32 patients with FES (FES). Large deformation diffeomorphic metric mapping (LDDMM) algorithms were used to delineate and assess the thalamic shape from MRI scans. The thalamic white matter integrity was quantified by fractional anisotropy (FA) and mean diffusivity (MD) averaged over the thalamus using DTI. Our analysis revealed that FES did not differ from CON in FA and MD but did differ markedly from them in the thalamic volume and shape. Patients with FES also performed poorly in spatial working memory and executive tasks. The correlation study found that regional thalamic shapes highly correlate with the two cognitive scores in the entire sample and healthy comparison controls but not in patients with FES even though no correlation was found between the thalamic volumes with the two cognitive scores in any group. Left thalamic FA was correlated with spatial working memory deficits in FES. Our findings suggest that thalamic volume and shape abnormalities are evident at the onset of FES prior to thalamic abnormal white matter integrity. Altered microstructural white matter integrity assessed using DTI may not be apparent in FES but may be observed as the disease progresses. Cognitive deficits related to spatial working memory and executive functioning in FES were observed in the context of loss of their normal relationship with the thalamic shapes, that is, regionally-specific thalamic shape compression is associated with poor performance in executive functioning and spatial working memory.     

White matter hemisphere asymmetries in healthy subjects and in schizophrenia: a diffusion tensor MRI study

Hemisphere asymmetry was explored in normal healthy subjects and in patients with schizophrenia using a novel voxel-based tensor analysis applied to fractional anisotropy (FA) of the diffusion tensor. Our voxel-based approach, which requires precise spatial normalization to remove the misalignment of fiber tracts, includes generating a symmetrical group average template of the diffusion tensor by applying nonlinear elastic warping of the demons algorithm. We then normalized all 32 diffusion tensor MRIs from healthy subjects and 23 from schizophrenic subjects to the symmetrical average template. For each brain, six channels of tensor component images and one T2-weighted image were used for registration to match tensor orientation and shape between images. A statistical evaluation of white matter asymmetry was then conducted on the normalized FA images and their flipped images. In controls, we found left-higher-than-right anisotropic asymmetry in the anterior part of the corpus callosum, cingulum bundle, the optic radiation, and the superior cerebellar peduncle, and right-higher-than-left anisotropic asymmetry in the anterior limb of the internal capsule and the anterior limb's prefrontal regions, in the uncinate fasciculus, and in the superior longitudinal fasciculus. In patients, the asymmetry was lower, although still present, in the cingulum bundle and the anterior corpus callosum, and not found in the anterior limb of the internal capsule, the uncinate fasciculus, and the superior cerebellar peduncle compared to healthy subjects. These findings of anisotropic asymmetry pattern differences between healthy controls and patients with schizophrenia are likely related to neurodevelopmental abnormalities in schizophrenia.     

Abnormal brain connectivity in first-episode psychosis: a diffusion MRI tractography study of the corpus callosum

A model of disconnectivity involving abnormalities in the cortex and connecting white matter pathways may explain the clinical manifestations of schizophrenia. Recently, diffusion imaging tractography has made it possible to study white matter pathways in detail and we present here a study of patients with first-episode psychosis using this technique. We selected the corpus callosum for this study because there is evidence that it is abnormal in schizophrenia. In addition, the topographical organization of its fibers makes it possible to relate focal abnormalities to specific cortical regions. Eighteen patients with first-episode psychosis and 21 healthy subjects took part in the study. A probabilistic tractography algorithm (PICo) was used to study fractional anisotropy (FA). Seed regions were placed in the genu and splenium to track fiber tracts traversing these regions, and a multi-threshold approach to study the probability of connection was used. Multiple linear regressions were used to explore group differences. FA, a measure of tract coherence, was reduced in tracts crossing the genu, and to a lesser degree the splenium, in patients compared with controls. FA was also lower in the genu in females across both groups, but there was no gender-by-group interaction. The FA reduction in patients may be due to aberrant myelination or axonal abnormalities, but the similar tract volumes in the two groups suggest that severe axonal loss is unlikely at this stage of the illness.     

基于DTI的三叉神经痛脑白质结构异常及其与临床特征的相关性

目的 采用基于纤维束的空间统计方法（TBSS）探讨原发性三叉神经痛（PTN）患者脑白质微结构异常。方法 对38例PTN患者（PTN组）和38名年龄、性别匹配的健康志愿者（对照组）行全脑DTI扫描,并用FSL软件进行分析,寻找FA值、平均扩散系数（MD）、径向扩散系数（RD）和轴向扩散系数（AD）存在组间统计学差异的脑区,并与视觉模拟评分（VAS）进行相关分析。结果 与对照组相比,PTN组胼胝体、放射冠、左侧上纵束、左侧下纵束及下额枕束FA值降低;且PTN组双侧丘脑后辐射、双侧内囊、双侧外囊、穹窿、右侧上纵束同时存在MD值和RD值升高,而AD升高脑区仅局限于双侧内囊前支、左侧内囊后支、双侧上放射冠和双侧上纵束。PTN患者左侧上纵束FA值与VAS呈负相关（r=-0.502,P=0.001）,左侧上纵束MD值与VAS评分呈正相关（r=0.437,P=0.006）。结论 丘脑、内囊MD值和RD值同向升高而不伴FA值降低可能是PTN的相对特征性DTI表现;左侧上纵束FA值和MD值对评估PTN患者疼痛水平有参考价值。     

基于纤维束骨架的空间统计方法研究维持性透析终末期肾病患者脑白质结构变化

目的 探讨基于纤维束骨架的空间统计方法研究维持性透析终末期肾病（ESRD）患者脑白质微结构变化。方法 采用3.0T MR仪对32例行维持性血透的ESRD患者和30名健康对照行DTI扫描,应用基于纤维束骨架的空间统计（TBSS）方法分析DTI多参数图,获得部分各向异性分数（FA）、平均弥散度（MD）、轴向弥散度（AD）及径向弥散度（RD）有显著差异的脑区。将ESRD患者差异脑区FA值与简易精神状态测试（MMSE）评分进行偏相关分析。结果 与健康对照比较,ESRD患者双侧额叶白质、双侧前辐射冠、胼胝体体部及膝部、左侧颞叶白质及多条联络纤维FA值显著减低;MD值呈广泛且对称性显著升高;右侧上纵束、左侧上辐射冠AD值显著升高,左侧丘脑前辐射AD值显著降低;双侧额叶、胼胝体及双侧上纵束等白质区RD值显著升高（P均<0.05）。右侧额叶白质（r=0.404,P=0.022）及左侧上纵束（r=0.475,P=0.006）FA值与MMSE评分呈正相关。结论 ESRD患者脑区白质微结构受损,可能导致其认知障碍。     

Is left fronto-temporal connectivity essential for syntax? Effective connectivity, tractography and performance in left-hemisphere damaged patients

Syntactic processing typically engages left inferior frontal gyrus and posterior middle temporal gyrus, and damage to these regions is associated with syntactic deficits. What has not been directly determined, however, is whether it is the effective connectivity between these regions - and therefore also the integrity of the white matter tracts that connect them - that underpins successful syntactic analysis. We addressed these related issues by obtaining measures of the psycho-physiological interaction between frontal and temporal regions and of the integrity of the major white matter tracts that directly connect them - the arcuate fasciculus and extreme capsule fibre system. We correlated these estimates with performance measures of syntax in a group of patients with left hemisphere damage and varying degrees of syntactic impairment. Good syntactic function was associated with enhanced effective connectivity and increased tract integrity, suggesting that intact connectivity between left frontal and temporal regions is essential for syntactic analysis rather than the activation of these regions per se.