颞叶癫痫患者执行功能的功能磁共振研究

目的 探讨颞叶癫痫(temporal lobe epilepsy ,TLE)患者执行功能的脑功能状态及激活模式.方法 应用注意网络测试(attentional networks test,ANT)软件,对12例TLE患者及12名健康受试者进行执行功能行为学测试;应用组块式功能磁共振(functional magnetic resonance imaging ,fMRI)扫描,使用统计参数图(Statistical Parametric Mapping 2,SPM 2)软件分析fMRI数据.结果 与健康受试组比较,TLE患者组执行功能反应时间(RT)较慢[患者组:(158.9±50.2)ms;健康受试组:(112.4±28.3)ms, t=2.63,P<0.05].健康受试组执行功能fMRI显示激活脑区右侧半球偏侧化,位于右扣带回后部、颞下回、前额叶、海马、顶叶及左颞中回.TLE患者组右侧前额叶和右额叶 (激活体素:53,34 voxel P<0.01)等靠近中线脑区激活体素较小.健康受试组存在与反应时间正、负相关脑区(P<0.001),TLE组则仅存与反应时间正相关脑区(P<0.001).结论 TLE患者存在执行功能障碍,与上述脑区激活功能低下和失调控有关,这些脑区可能是TLE患者执行功能损害的形态学基础.     

颞叶癫痫患者磁共振弥散张量成像及记忆损害的研究

目的利用磁共振弥散张量成像技术(DTI)研究颞叶癫痫(TLE)患者脑内微观改变及记忆损害的相关脑区。方法对颞叶癫痫患者15例和健康对照者15例,进行DTI检查,利用韦氏记忆量表检测记忆功能。结果 TLE患者部分各向异性弥散(FA)值降低激活区域有颞叶、边缘叶、扣带回和岛叶,升高区有:额叶、顶叶、枕叶,表观系数(ADC)值升高激活区域在颞叶、额叶、枕叶、顶叶;无ADC值降低区域。与健康者相比,颞叶癫痫患者的记忆商数(MQ)(90.73±19.72)显著下降,P<0.01。对照组FA值在左岛叶、颞叶与MQ值正相关;患者组FA值在右额、顶、枕叶、左顶叶与MQ值正相关,在左颞叶与MQ值负相关。对照组ADC与MQ正相关区域在左边缘叶,与MQ成负相关区域在左顶叶、患者组正相关区域在左、右颞叶。结论初步证实TLE患者的脑内结构变化不局限于颞叶,还包括颞叶外网络结构;TLE患者全脑DTI与MQ存在着相关激活脑区,表明记忆功能损害与脑内相关结构改变有关。     

右侧颞叶癫痫的静息态大脑熵改变及与警觉的关系

目的应用静息态功能磁共振成像研究右侧颞叶癫痫(right temploal lobe epilepsy,r TLE)患者大脑熵的改变及其与警觉功能的关系。方法利用注意网络测试(attention network test,ANT)对20名r TLE患者和22名健康对照者的警觉功能进行研究;同时计算两组被试静息态功能磁共振(resting-state functional magnetic resonance,rs-f MRI)下的大脑熵(Brain Entropy,BEN),并选取两组的差异脑区(P0.01)作为感兴趣区(region of interesting,ROI),提取熵值和各区的部分各向异性指数(fractional anisotropy,FA)值;分别对大脑熵值、FA值和警觉功能之间关系进行研究。结果与正常人相比,r TLE患者的固有警觉和位相性警觉反应时间显著增加;大脑熵在右颞下回、左额上回眶部显著增加,在右侧楔前叶、左侧顶上小叶等脑区显著降低;左额上回眶部的FA值较正常对照显著减小;固有警觉反应时间与左额上回眶部熵值呈正相关,与右侧楔前叶、左中央后回熵值呈负相关;位相性警觉反应时间与左额上回眶部的FA值、右侧楔前叶熵值及左中央后回熵值呈负相关。结论 r TLE患者警觉功能的下降与某些脑区其静息态大脑熵的改变和局部细微结构的损害有关,BEN作为一个新的指标可以用来研究癫痫患者脑功能。     

单侧颞叶癫痫患者注意功能及其影响因素的研究

目的探讨单侧颞叶癫痫患者注意功能的变化及其影响因素。方法采用注意网络测试(attention network test,ANT)软件对111例单侧颞叶癫痫患者(患者组)和77例健康志愿者(对照组)注意网络的各项指标进行测试及对比,并通过多元线性回归分析患者组差异指标的影响因素。结果患者组固有警觉反应时间(reaction time,RT)、位相性警觉RT、执行网络RT均长于对照组(P0.05),患者组警觉网络RT与定向网络RT与对照组相比差异无统计学意义(P0.05);影响患者执行网络RT的因素由大到小依次为EEG痫性放电、起病年龄,影响患者固有警觉RT与位相性警觉RT的因素由大到小依次为起病年龄、受教育年限。结论单侧颞叶癫痫患者存在执行网络效率降低、固有警觉和位相性警觉损害;痫性放电和起病年龄与执行网络效率有关,起病年龄和受教育年限与固有警觉及位相性警觉有关。     

语义记忆脑功能区偏侧化的功能磁共振成像研究

目的 通过功能磁共振成像(fMRI)技术检测健康人脑语义记忆功能区的分布特点.方法 14名右利手健康志愿者进行配对词语联想学习记忆任务时行fMRI扫描,该任务可有代表性地反映受试者的语义记忆.实验采用组块设计并选用SPM99软件行数据分析和脑功能区定位,记录各激活脑区的像素值并计算偏侧化指数LI值.结果 经单样本t检验,阈值设为P＜0.005时,记忆编码时主要激活脑区为左枕叶和左额上中回,提取时主要激活左顶叶、左枕叶和左额中下回;而右半球在两阶段均较少激活.编码和提取激活脑区像素值LI值分别为0.81和0.73.结论 语义记忆的脑功能区有显著的左半球优势;记忆编码和提取阶段所激活的脑区有所差别,但均主要分布于左外侧裂语言区的周围.     

空间记忆广度的脑功能磁共振研究

目的本实验拟通过功能磁共振研究参与正常人空间记忆广度任务的脑功能区和特点。方法10名右利手健康志愿者进行一项空间记忆广度任务作业的同时进行脑功能磁共振扫描,实验采用组块设计,实验任务与对照任务交替进行,数据采用SPM99软件进行数据分析和脑功能区定位。结果当统计阈值设定为P(0.0001时,被试者的双侧Brodmann区(Brodmann area,BA)6区(额中下回)、右BA9区(额中下回)、左额下回BA47区、双侧顶叶BA7区(楔前叶、顶上小叶)、双侧顶叶BA40区(缘上回),右枕叶BA18、19区、右海马回BA30区、左枕颞交界处BA37区、双侧顶叶中央后回BA3区、左顶叶中央后回BA2区、右中央前回BA4区及左中脑黑质、右小脑均有激活,以顶叶的激活最为显著,其次为额叶、枕叶,其中额叶的BA9区和枕叶的BA18、19区及海马回、小脑的激活有极其明显的右侧半球优势;当统计阈值设定为P(0.001时,脑激活区增加了右前扣带回BA25区,右侧额下回BA47区、左额叶BA9区,左侧枕叶BA17、18、19区及右屏状核,左丘脑侧后核。结论与空间记忆广度有关的主要脑区有BA9、6、7、40、19区和海马回、小脑。它们在进行短时空间记忆任务时所起的作用不同。通过fMRI的研究,揭示了大脑进行空间信息的处理过程。     

颞叶癫痫患者尾状核静息态及动态功能连接改变研究

目的利用功能磁共振(functional magnetic resonance imaging,f MRI)研究颞叶癫痫(temporal lobe epilepsy,TLE)患者尾状核静息态功能连接(resting-state functional connectivity,rs FC)及动态功能连接(dynamic functional connectivity,d FC)的变化,及其与执行功能的关系。方法对20例TLE患者和20例健康对照组,行注意网络测试(ANT)及f MRI扫描,比较以双侧尾状核为感兴趣区的脑功能连接差异,分析尾状核静息态及动态功能连接改变与执行控制网络效率的相关性。结果与对照组相比,TLE患者的执行功能受到损害(P 0. 05)。TLE患者组左侧尾状核与左侧小脑后叶rs FC减弱;与右侧前扣带回d FC方差减小。TLE患者组右侧尾状核与右侧额叶rs FC增强;与右侧中央后回d FC方差增大。TLE患者右侧尾状核与右侧额叶的静息态功能连接强度与执行控制网络效率呈正相关(r=0. 604,P=0. 005)。结论 TLE患者执行功能损害与尾状核相关,尾状核的执行控制网络受到破坏,网络内存在代偿重构机制。     

首发抑郁症局部脑区的功能一致性及其与临床症状的关系

目的通过静息态功能磁共振(fMRI),探讨首发抑郁症患者的自发脑活动特征及其与临床症状之间的关系。方法 16例首发未用药的符合DSM-IV诊断标准的重性抑郁障碍(抑郁症)患者和16名正常对照,在静息状态下接受5min12sfMRI扫描。以汉密尔顿抑郁量表(HAMD)评估患者临床症状,以ReHo软件对影像数据进行脑区的自发神经活动功能一致性分析。结果患者组左侧丘脑、左内外侧上颞叶、左侧小脑与枕叶的自发活动局部一致性较对照组减低(P0.01)。患者组上述差异脑区的ReHo值与HAMD总分无相关(P0.05),但左侧丘脑ReHo值与HAMD体重因子分、睡眠障碍因子分相关(r=0.56,P0.05;r=0.58,P0.05),左外侧上颞叶ReHo值与HAMD认知障碍因子分相关(r=0.51,P0.05),左内侧上颞叶ReHo值与HAMD焦虑躯体化因子分、认知障碍因子分相关(r=0.51,P0.05;r=0.53,P0.05)。结论首发抑郁症患者左侧丘脑、左侧上颞叶、左侧小脑与枕叶功能异常,且部分脑区自发活动一致性降低可能与患者某些症状相关。     

男性精神分裂症患者Stroop效应的脑功能磁共振成像研究

目的采用功能磁共振成像(fMRI)技术,探讨男性精神分裂症患者Stroop效应的行为学及脑区激活的特点。方法采用慢速事件-相关设计的Stroop-like任务,任务范式包括一致状态(CC)和不一致状态(IC)两种试验,对26例精神分裂症男性患者(患者组)和17名与患者组的年龄、受教育年限相匹配的正常人(对照组)进行fMRI检查。使用统计参数激活图(SPM2)及功能影像分析(AFNI)软件对图像进行分析。结果(1)在CC下,对照组的反应时间[(610.9±69.1)ms]短于患者组[(665.0±85.5)ms;P<0.05];在IC下,对照组的反应时间[(711.5±84.8)ms]虽短于患者组[(757.7±130.9)ms],但差异无统计学意义(P>0.05);两组IC的反应时间均长于CC(P<0.01)。两组脑激活图均未观察到IC较CC增加激活的脑区。(2)患者组表现为多个脑区的局部一致性下降,主要分布于右侧岛叶、额下回、颞下回,以及左侧扣带回前部、山顶(小脑)和额中回。结论男性精神分裂症患者的行为学存在明显的Stroop效应,而脑区激活却未见Stroop效应。     

健康人脑空间工作记忆的脑功能磁共振研究

目的 通过功能磁共振成像(unctional magnetic resonance imaging, fMRI)技术研究健康人脑空间工作记忆的功能脑区.方法 10名右利手健康志愿者进行空间工作记忆任务的同时进行fMRI扫描,实验采用组块设计和SPM99软件进行数据分析和脑功能区定位.结果 大脑皮质所激活的主要脑区有双侧顶叶(BA7/40,BA:Brodmann area,布鲁德曼分区),双侧额叶(BA6/9/47),双侧枕颞交界处(BA19/37);被激活的大脑皮质下结构有右侧尾状核、左侧丘脑和左侧中脑黑质;双侧小脑也均被显著激活(P<0.001).结论 人脑处理空间工作记忆信息是由大脑皮质下结构及小脑与大脑皮质共同完成的.     

Alertness network in patients with temporal lobe epilepsy: a fMRI study

Patients with temporal lobe epilepsy (TLE) often suffer from cognitive deficits. However, it remains elusive whether the performance of TLE patients in the attentional networks test (ANT) is impaired. Functional magnetic resonance imaging (fMRI) can accurately reflect the hemodynamics and functional activities in certain regions of the brain. In the current study, we aimed to investigate the characteristics and neural mechanisms of the functions of the alertness network in patients with TLE using the ANT and fMRI. A total of 12 patients with TLE and 8 healthy controls underwent the ANT behavioral tests and subsequent block-design fMRI scanning. The results showed that the response times of the alertness network had no significant difference between the TLE group and the healthy control group. The fMRI data showed that the activation of the cerebellum, right occipital lobe, right frontal and brainstem was significantly weaker in TLE patients than in healthy control. Our data indicate that despite neuropsychological test performance is normal; the alerting network is deficient in the TLE patients. The decreased activation of brain regions of right occipital lobe, cerebellum, right frontal lobe, brain stem and temporal lobe may be the neural basis of altering network impairment in TEL patients.     

Neural correlates of the attention network test in schizophrenia

Attentional deficits are prominent in schizophrenia, affecting nearly all cognitive functions. Human attention comprises three essential components: alerting, orienting and executive control. For the assessment of these functions, the attention network test (ANT) has been proposed and used in healthy controls and patients. In schizophrenia, the ANT has revealed behavioral deficits; however, the corresponding neural correlates have not been examined. In the present study, neural correlates of attention were investigated in 17 schizophrenia patients and 17 healthy controls using the ANT with fMRI. Behavioral deficits emerged in the alertness system with a reduced efficiency for temporal cues. In fMRI, changes were observed for all three domains-alerting, orienting and conflict-and revealed hyper- as well as hypoactivation in patients. Affected regions during alerting comprised a broad fronto-temporo-parieto-occipito-cerebellar network, while differences during orienting mainly tapped fronto-parietal regions and during conflict processing a thalamo-frontal-temporal occipital network including the postcentral regions. In general, hyperactivations were positively correlated with more severe psychopathologial symptoms.     

颞叶癫痫患者注意网络的研究

目的探讨颞叶癫痫患者注意网络的状况及影响因素。方法连续收录2007年1月至2008年12月在我院就诊的44例颞叶癫痫患者,选择相匹配的健康志愿者40名作为对照研究。应用注意网络测试(attentional networks test,ANT)软件,评估被试者注意网络状况,比较两组注意网络各指标的差异,采用非条件Logistic分析受教育年限、病程等因素对注意网络指标的影响。结果与对照组比较,患者组的ANT平均反应时间较慢[患者组:(688.2±138.1)ms;对照组:(625.1±100.1)ms,t=2.06,P0.05];患者组ANT中执行功能效率显著下降[患者组:(155.7±57.0)ms;对照组:(108.0±33.8)ms,t=4.62,P0.01];两组MMSE、ANT的警觉功能与定向功能效率无统计学差异。非条件Logistic分析显示,存在脑电图痫性放电(95%CI:1.03～42.33,OR=6.603,P=0.043)为患者执行功能损害可能原因。结论初步证实颞叶癫痫患者存在注意网络的执行功能损害,痫性放电可能是导致患者注意执行功能损害的原因。     

丙泊酚wada试验与功能磁共振在癫痫语言优势侧评估中的应用

目的探讨丙泊酚wada试验与fMRI在术前语言优势侧评估中的一致性与预测术后言语及整体智力变化的敏感性。方法对8名左颞叶癫痫患者术前丙泊酚Wada试验和fMRI语言优势侧结果进行比较,独立样本t检验比较两种方法判定的左侧优势组与非左侧优势组手术前后平均VIQ、FIQ变化的差异。结果两者语言优势侧判定一致率为71%,fMRI语言优势为左侧的患者术后平均FIQ、VIQ下降较非左侧组患者显著(P≤0.05),丙泊酚wada试验分组则无显著差异(P>0.05)。结论丙泊酚wada试验与fMRI在癫痫术前语言功能评估中有较高的一致性,从微创、经济和偏侧化预测的一致性及敏感性角度综合考虑,fMRI比Wada试验的优势更明显。     

Neural correlates of attentional deficits in Parkinson's disease patients with mild cognitive impairment

IntroductionDeficits in attentional processing observed in Parkinson's disease (PD) patients with mild cognitive impairment (MCI) increase risk of PD dementia. However, the neural basis of these attentional deficits are presently unknown. The present study aimed to explore the neural correlates of attention dysfunction in PD-MCI using the Attention Network Test (ANT) and functional Magnetic Resonance Imaging (fMRI).MethodFifteen (15) PD-MCI patients, 26 PD patients without MCI (PD-NC) and 22 healthy controls (HC) were scanned (3T Siemens PRISMA) whilst performing the ANT. Reaction time, accuracy and fMRI BOLD activation were compared between groups for the three attentional task components of 1) alerting, 2) orienting, and 3) executive control.ResultsPD-MCI patients showed an overall slower reaction time compared to PD-NC and HC, and showed less interference of reaction time in the orienting effect than HC. fMRI data demonstrated greater activation in the bilateral cerebellum crus 1 during the alerting attention condition in both PD-MCI and PD-NC compared to HC. However, activation was supressed in the left postcentral gyrus in PD-MCI compared to PD-NC and HC.DiscussionAlterations in the alerting attention functional network despite intact task performance in PD-MCI suggests that functional brain changes may precede cognitive changes in the attention domain. Furthermore, increased activation in the cerebellum may reflect an attentional compensatory mechanism unique to the PD pathology. Taken together, the findings suggest that PD has a complex effect on attentional ability that can, at least in part, be elucidated using functional neuroimaging.     

Language lateralization by Wada test and fMRI in 100 patients with epilepsy

Comparing the determination of language dominance using fMRI with results of the Wada test in 100 patients with different localization-related epilepsies, the authors found 91% concordance between both tests. The overall rate of false categorization by fMRI was 9%, ranging from 3% in left-sided temporal lobe epilepsy (TLE) to 25% in left-sided extratemporal epilepsy. Language fMRI might reduce the necessity of the Wada test for language lateralization, especially in TLE.     

Language lateralization in temporal lobe epilepsy using functional MRI and probabilistic tractography

Purpose: Language functional magnetic resonance imaging (fMRI) is used to noninvasively assess hemispheric language specialization as part of the presurgical work-up in temporal lobe epilepsy (TLE). White matter asymmetries on diffusion tensor imaging (DTI) may be related to language specialization as shown in controls and TLE. To refine our understanding of the effect of epilepsy on the structure–function relationships, we focused on the arcuate fasciculus (ArcF) and the inferior occipitofrontal fasciculus (IOF) and tested the relationship between DTI- and fMRI-based lateralization indices in TLE.
Methods: fMRI with three language tasks and DTI were obtained in 20 patients (12 right and 8 left TLE). The ArcF, a major language-related tract, and the IOF were segmented bilaterally using probabilistic tractography to obtain fractional anisotropy (FA) lateralization indices. These were correlated with fMRI-based lateralization indices computed in the inferior frontal gyrus (Pearson's correlation coefficient).
Results: fMRI indices were left-lateralized in 16 patients and bilateral or right-lateralized in four. In the ArcF, FA was higher on the left than on the right side, reaching significance in right but not in left TLE. We found a positive correlation between ArcF anisotropy and fMRI-based lateralization indices in right TLE (p < 0.009), but not in left TLE patients. No correlation was observed for the IOF.
Conclusions: Right TLE patients with more left-lateralized functional activations also showed a leftward-lateralized arcuate fasciculus. The decoupling between the functional and structural indices of the ArcF underlines the complexity of the language network in left TLE patients.     

Lateralization of temporal lobe epilepsy using resting functional magnetic resonance imaging connectivity of hippocampal networks

Purpose: Early surgical intervention can be advantageous in the treatment of refractory temporal lobe epilepsy (TLE). The success of TLE surgery relies on accurate lateralization of the seizure onset. The purpose of this study was to determine whether resting functional MRI (fMRI) connectivity mapping of the hippocampus has the potential to complement conventional presurgical evaluations in distinguishing left from right TLE. In addition, we sought to determine whether this same network might separate patients with favorable from unfavorable postoperative outcomes. Methods: Resting fMRI acquisitions were performed on 21 patients with TLE and 15 healthy controls. The patients included seven patients with left TLE and seven patients with right TLE with seizure-free postoperative outcome, and five patients with left TLE and two patients with right TLE with recurring seizures after surgery. Functional connectivity maps to each hippocampus were determined for each subject and were compared between the controls and the seizure-free patients with left TLE and with right TLE. The one network identified was then quantified in the patients with TLE and recurring seizures. Key Findings: The resting functional connectivity between the right hippocampus and the ventral lateral nucleus of the right thalamus was the most statistically significant network to distinguish between seizure-free patients with left TLE and with right TLE with high sensitivity and specificity. This connectivity was also significantly greater in the seizure-free patients with left TLE than the healthy controls. Finally, six of the seven patients in whom seizures recurred after surgery had connectivity values in this network unlike those who were seizure-free. Significance: This study identified a region in the ventral lateral nucleus of the right thalamus whose connectivity to the hippocampi separates left from right TLE subjects. This suggests that the quantification of resting-state functional magnetic resonance imaging (MRI) connectivity across this network may be a potential indicator of lateralization of TLE that may be added to other presurgical MRI assessments. Further validation in a larger, independent cohort is required.     

Assessing the function of the fronto‐parietal attention network: Insights from resting‐state fMRI and the attentional network test

In the recent past, various intrinsic connectivity networks (ICN) have been identified in the resting brain. It has been hypothesized that the fronto‐parietal ICN is involved in attentional processes. Evidence for this claim stems from task‐related activation studies that show a joint activation of the implicated brain regions during tasks that require sustained attention. In this study, we used functional magnetic resonance imaging (fMRI) to demonstrate that functional connectivity within the fronto‐parietal network at rest directly relates to attention. We applied graph theory to functional connectivity data from multiple regions of interest and tested for associations with behavioral measures of attention as provided by the attentional network test (ANT), which we acquired in a separate session outside the MRI environment. We found robust statistical associations with centrality measures of global and local connectivity of nodes within the network with the alerting and executive control subfunctions of attention. The results provide further evidence for the functional significance of ICN and the hypothesized role of the fronto‐parietal attention network. Hum Brain Mapp 35:1700–1709, 2014. © 2013 Wiley Periodicals, Inc.     

Functional connectivity homogeneity correlates with duration of temporal lobe epilepsy

Temporal lobe epilepsy (TLE) is often associated with progressive changes to seizures, memory, and mood during its clinical course. However, the cerebral changes related to this progression are not well understood. Because the changes may be related to changes in brain networks, we used functional connectivity MRI (fcMRI) to determine whether brain network parameters relate to the duration of TLE. Graph theory-based analysis of the sites of reported regions of TLE abnormality was performed on resting-state fMRI data in 48 subjects: 24 controls, 13 patients with left TLE, and 11 patients with right TLE. Various network parameters were analyzed including betweenness centrality (BC), clustering coefficient (CC), path length (PL), small-world index (SWI), global efficiency (GE), connectivity strength (CS), and connectivity diversity (CD). These were compared for patients with TLE as a group, compared to controls, and for patients with left and right TLE separately. The association of changes in network parameters with epilepsy duration was also evaluated. We found that CC, CS, and CD decreased in subjects with TLE compared to control subjects. Analyzed according to epilepsy duration, patients with TLE showed a progressive reduction in CD. In conclusion, we found that several network parameters decreased in patients with TLE compared to controls, which suggested reduced connectivity in TLE. Reduction in CD associated with epilepsy duration suggests a homogenization of connections over time in TLE, indicating a reduction of the normal repertoire of stronger and weaker connections to other brain regions.