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。     

偏执型精神分裂症患者Stroop操作的功能磁共振研究

目的利用功能磁共振显像(fMRI)技术探讨精神分裂症患者注意障碍的脑功能基础。方法对14例精神分裂症患者(患者组)和16名正常人(对照组)检测Stroop测验刺激下的fMRI。结果(1)激活脑区计数(个)：Stroopl刺激下,患者组左侧额下回(11/3)、左侧颞上回(6/8)、左侧颞下回(6/8)脑区激活计数均多于对照组(分别为6/10、1/15、1/15),差异有统计学意义(P＜0.05)；Stroop2刺激下,患者组左侧前扣带皮质(ACC,4/10)、右侧额中回脑区激活计数(4/10)均少于对照组(分别为12/4、14/2),差异有统计学意义(P＜0.05),患者组左额上回激活计数(9/5)多于对照组(3/ 13),差异有统计学意义(P＜0.05)。(2)激活脑区体积(体素)：Stroop1刺激下,患者组右侧前额叶背外侧区(DLPFC,256±579)、左侧ACC(18±59)激活体积小于对照组(分别为298±597、67±87),差异有统计学意义(P＜0.05)；Stroop2刺激下,患者组两侧DLPFC(分别为73±190、80±245)、左侧ACC(17±28)激活体积小于对照组(分别为425±800、414±703、76±98),差异有统计学意义(P＜0.05)。结论精神分裂症患者的注意障碍可能与前额叶、ACC、颞叶神经回路功能障碍密切相关。     

针刺内关穴对阿尔茨海默病脑功能磁共振成像的影响

目前,随着社会老龄化,关于老年痴呆的中西医研究较多,但尚无针刺治疗对阿尔茨海默病 (Alzheimer’sdisease,AD)患者脑功能成像方面的研究报道,我们于 2004年 3—8月通过针刺内关穴研究针刺对AD患者脑功能活动的影响,旨在找到AD治疗的客观基础。对象和方法1. 研究对象: 6例A     

阿尔茨海默病患者脑白质损害与认知功能的关系

目的用磁共振扩散张量成像(DTI)研究阿尔茨海默病(AD)患者脑白质损害的特点及其与认知功能改变的相关性。方法对16例AD患者和12名年龄及性别相当的健康老年人行DTI、T1液体衰减反转恢复序列(FLAIR)及T2-FLAIR检查,测量胼胝体膝部和压部、内囊前肢和后肢、额颞顶枕叶白质的部分各向异性分数值(FA)和平均弥散度(MD),分析FA、MD值与简易精神状态量表(MMSE)评分之间的相关关系。结果AD患者胼胝体压部、额叶、顶叶、颞叶FA值分别为0.602±0.043、0.270±0.034、0.294±0.043、0.302±0.032,与健康老人组相比显著下降(P<0.05),且与MMSE评分呈正相关关系,而内囊前后肢、枕叶、胼胝体膝部的FA值则无明显变化(P>0.05);胼胝体压部、顶叶白质的MD值分别为(0.918±0.029)、(0.826±0.015)×10-9m2/s,与健康老人组相比显著升高(P<0.01),且与MMSE评分呈负相关,而内囊前后肢、额叶、颞叶、枕叶和胼胝体膝部的MD值则无明显变化(P>0.05)。结论AD患者表现为脑白质的选择性损害,且损害程度与认知功能密切相关;这种选择性损害反映了AD病理机制中皮质-皮质及皮质-皮质下联系的丢失;DTI技术可以用来监测疾病的进展情况及评价AD治疗药物的临床疗效。     

轻度阿尔茨海默病患者的注意功能反应时研究

目的了解轻度阿尔茨海默病(A lzhe im er d isease,AD)患者的各类注意功能的改变。方法对轻度AD患者应用计算机上持续操作任务(continuous perform ance task,CPT)法检查持续注意功能,简化的Stroop法测查选择注意功能,双任务测试检查分散注意能力,反应时精确到毫秒。结果CPT法中,轻度AD组反应时、漏报率和虚报率均高于健康对照组[(539.29±103.86)m s vs(458.47±40.87)m s,4.08%(3.13%,13.64%)vs 0.91%(0.60%,1.90%),1.51%(0.64%,2.54%)vs 0.43%(0.37%,0.84%),P<0.01];异常率随时间增高,10~14 m in增高明显[6.09%(4.87%,20.73%)vs 2.43%(2.43%,3.04%),P<0.01]。Stroop实验中,2组被试均表现出明显的干扰效应;轻度AD组患者的反应时、错误率和错误率干扰量高于对照组[(579.19±89.93)m s vs(486.75±51.58)m s,13.33%(8.75%,17.50%)vs 2.92%(1.67%,3.96%),错误率干扰量,均P<0.01]。双任务测试中AD组双任务减退量高于对照组(P<0.01)。CPT法和Stroop法异常率高于双任务测试,分别为77.78%、81.25%、29.41%。结论与健康老年人相比,轻度AD患者的持续注意、选择注意和分散注意能力下降,持续注意及选择注意障碍较突出。     

阿尔茨海默病患者血-脑屏障功能障碍神经影像学研究进展

近年研究表明血-脑屏障功能障碍在认知功能障碍和痴呆的病理生理学机制中扮演重要角色。血-脑屏障可以调节脑微环境稳态,调控营养物质(如葡萄糖和氨基酸)转运,阻止血源性产物、病原体和神经毒性物质进入脑组织。神经影像学技术可以实现血-脑屏障完整性破坏的定位和定量分析,为阐明阿尔茨海默病发病机制提供新的切入点。     

静息态功能磁共振成像观察阿尔茨海默病患者大脑自发活动特点

目的 运用静息态功能磁共振成像(fMRI)技术探测老年阿尔茨海默病(AD)患者大脑自发活动特点.方法 选择23例AD患者(AD组)和21名健康志愿者(NC组),分别接受神经心理学检查(MMSE、听觉词语学习测试)和静息态fMRI扫描,比较两组间神经心理评分和局部一致性(ReHo)的差异.结果 AD组(分)MMSE(20±4)、听觉词语学习测试即刻回忆(2.6±1.6)、延迟回忆(0.4±0.7)及再认成绩(5.8±3.7)均低于NC组(29±1、5.9±1.2、5.5±2.0、9.2±1.1,T=10.58、7.21、10.99、3.96,均P＜0.01);当设置单个体素统计阈值为P＜ 0.01、激活簇≥100体素时,与NC组比较,AD组在前额叶内侧面、后扣带回及楔前叶、右侧颞上回、两侧顶上小叶及顶下小叶等默认网络脑区ReHo值降低;在左侧壳核、丘脑的ReHo值增高.结论 AD患者存在大脑默认功能网络异常;而在壳核、丘脑的自发活动增强,可能是大脑皮质下结构对默认系统功能降低的代偿反应.     

单相和双相抑郁障碍患者前扣带回功能连接特征差异观察北大核心CSCD

目的比较单、双相抑郁障碍前扣带回功能连接的差异,探讨前扣带回功能连接与抑郁症状严重程度的关系。方法利用fMRI技术,对符合DSM-Ⅳ诊断标准的30例单相抑郁障碍(unipolar depression)患者(单相抑郁组)、30例双相抑郁障碍(bipolar depression)患者(双相抑郁组)及年龄、性别、受教育程度相匹配的32名对照者(对照组)进行静息态fMRI扫描,以前扣带回为感兴趣区进行功能连接分析,比较组间差异,并对功能连接强度与抑郁症状的严重程度之间的关联进行Pearson相关分析。结果(1)与对照组相比,单相抑郁组左侧前扣带回与左侧三角部额下回(t=3.48)、左侧顶下缘角回(t=3.15)之间的功能连接增强,右侧前扣带回与左侧三角部额下回(t=3.52)之间的功能连接增强;(2)与对照组相比,双相抑郁组左侧前扣带回与右侧颞中回(t=-4.00)之间的功能连接减低,右侧前扣带回与左侧中央后回(t=-3.46)、右侧颞上回(t=-2.86)、右侧颞中回(t=-3.40)之间的功能连接减低;(3)与双相抑郁组相比,单相抑郁组左侧前扣带回与左侧三角部额下回(t=3.58)、右侧三角部额下回(t=4.06)、右侧颞中回(t=3.25)、左侧顶下缘角回(t=3.27)、右侧顶下缘角回(t=3.99)之间的功能连接增强;右侧前扣带回与左侧三角部额下回(t=3.13)、左侧顶下缘角回(t=3.42)、右侧顶下缘角回(t=3.78)之间的功能连接增强(均采用Alphasim校正,P<0.001);(4)Pearson相关分析显示,以上差异脑区功能连接强度与HAMD17总分均无相关性(-0.20.05)。结论静息态下单相抑郁患者前扣带回功能连接增强,双相抑郁患者前扣带回功能连接减弱;单、双相抑郁障碍差异脑区功能连接强度与临床症状无相关性。     

抑郁症首次发作患者情绪偏向任务的脑功能磁共振成像研究

目的 研究抑郁症首次发作(以下简称首发)患者对不同性质情绪线索的差异脑激活反应,以探讨抑郁症患者"负性情绪偏向性"的脑活动特征.方法 14例抑郁症首发患者与14名配对健康对照者,接受国际情绪图片系统中正性-中性-负性三组图片刺激的脑功能磁共振成像(fMRI)扫描,任务为组块设计;以文拉法辛(75～150 mg/d,口服)治疗患者,随访12周;以汉密尔顿抑郁量表(HAMD17)减分率评估疗效;用神经功能影像分析(AFNI)软件处理影像数据.结果 (1)文拉法辛治疗8周时有效率为58%;12周时有效率为92%,HAMD17总分减分率为60%.(2)两组均激活的脑区包括双侧额中回、双侧背外侧前额叶皮质、左侧丘脑、双侧岛叶、双侧颞叶、双侧杏仁核和海马.(3)在正性/中性图片激活的脑区中,患者组双侧额中回(右侧0.11%,左侧0.09%)及左侧丘脑(0.31%)激活强度均低于对照组(分别为0.98%,1.17%和1.32%;P＜0.05);左侧岛叶(1.03%)及双侧杏仁核(右侧0.47%,左侧0.11%)的激活强度高于对照组(分别为0.45%,-0.34%和-0.49%;P＜0.05).对于负性图片,患者组左侧额中回(2.77%)、左背外侧前额叶皮质(0.18%)、左侧岛叶(1.36%)、左侧颞叶(0.33%)和右侧杏仁核(0.44%)的激活强度高于对照组(分别为1.91%.-0.32%.0.91%,-0.31%,-0.29%;P＜0.05);患者组左侧丘脑激活强度(-0.79%)低于对照组(1.15%;P＜0.05).(4)治疗后,对于正性图片,患者组左侧、右侧额中回及左侧丘脑激活增加为1.21%,1.14%及1.23%(P＜0.05).对于负性图片,左侧额中回(2.05%)、左外侧前额叶皮质(-0.42%)及左侧岛叶(0.73%)的激活降低(P＜0.05);左侧丘脑(1.53%)激活增加(P＜0.05).结论 前额叶、左侧岛叶、左侧颞叶、杏仁核和左侧丘脑对不同性质情绪诱导线索的异常激活,与抑郁症首发患者偏向性情绪障碍相关;文拉法辛对前额叶、左侧岛叶和丘脑的异常激活有调节作用.     

静息状态功能磁共振成像观察轻度阿尔茨海默病后扣带回功能连通性的变化

目的 利用静息状态功能磁共振成像(fMRI)研究阿尔茨海默病(AD)早期后扣带回相关的静息脑网络连通性是如何变化的.方法 运用fMRI研究了16例轻度AD患者和16名健康对照者在静息状态后扣带回的功能连通性.与后扣带回有功能连通性的脑区是通过检测低频波动信号的时程相关性获得的.应用通用的SPM2图像统计软件计算组间和组内连通性差异,激活区阈值设置:P<0.01(校正),像素范围>5.利用SPM2软件随机效应分析t检验(经校正P<0.01,t=2.47,像素范围>5),比较患者组和对照组连通性激活的脑区.结果 与后扣带回有功能连通性减弱的脑区包括前额叶中线区、楔前叶、双侧视皮质、双侧颞下回、左侧海马、右侧丘脑、右侧额叶背外侧区;偏左侧化的连通性增高的脑区包括前额叶中线区、左侧颞下回、左侧基底节区、双侧额叶背外侧区及左侧中央前区.结论 与后扣带回相关的静息状态脑网络连通性减低与AD早期情节记忆损害和高级视觉功能损害有关系,轻度AD保留着功能连接的重塑性以便维持脑功能.静息fMRI是一种探索AD脑功能机制的适宜方法.     

fMRI brain activation during a delay discounting task in HIV-positive adults with and without cocaine dependence

Cocaine use is associated with poorer HIV clinical outcomes and may contribute to neurobiological impairments associated with impulsive decision making. This study examined the effect of cocaine dependence on brain activation during a delay discounting task involving choices between smaller immediate rewards and larger delayed ones. Participants were 39 HIV-positive adults on antiretroviral therapy who had current cocaine dependence (“active,” n = 15), past cocaine dependence (“recovered,” n = 13), or no lifetime substance dependence (“naïve,” n = 11). Based on responses on a traditional delay discounting task, three types of choices were individualized for presentation during functional magnetic resonance imaging: hard (similarly valued), easy (disparately valued), and no (single option). Active participants had significantly smaller increases in activation than naïve participants during hard versus easy choices bilaterally in the precentral gyrus and anterior cingulate cortex and in the right frontal pole (including dorsolateral, ventrolateral, and orbitofrontal cortex). During hard and easy choices relative to no choices, active participants had smaller increases in activation compared to naïve participants in frontoparietal cortical regions. These deficits in the executive network during delay discounting choices may contribute to impulsive decision making among HIV-positive cocaine users, with implications for risk behaviors associated with disease transmission and progression.     

抑郁症患者脑的磁共振研究

目的;采用磁共振技术（MRI）分析抑郁症患者的脑结构改变。方法：以抑郁症患者32例为病例组,正常23例为对照组,作头颅磁共振扫描。结果：病例组第3脑室横径,双侧外侧裂宽度显著增宽,透明中隔至额极距离减少。结论：抑郁症患者额、颞叶均明显萎缩。     

血管性认知障碍不同亚型患者认知功能及MRI检查的对比研究

目的探讨血管性认知障碍各亚型患者之间及其与认知功能正常者之间的认知功能及脑组织影像学表现的差异。方法采用简易智能状态检查量表、认知能力筛查量表和简易智能-认知能力联合检查量表对62例血管性认知障碍患者(无痴呆型血管性认知障碍34例、血管性痴呆18例、混合性痴呆10例)和50例正常对照者的认知功能进行评价,通过磁共振成像分析其容积测量值、脑叶萎缩、皮质下白质疏松和腔隙性脑梗死等影像学参数的差异。结果与对照组比较,血管性认知障碍各亚组患者认知功能评分呈逐步递减趋势(均P<0.05),但血管性痴呆与混合性痴呆患者之间差异无统计学意义(P>0.05)。血管性认知障碍各亚组患者双侧前额角容积、第三脑室容积测量值以及额叶、颞叶、顶叶、枕叶萎缩,皮质下白质疏松和腔隙性脑梗死评分均高于对照组(P<0.05),其影像学异常改变在进展为痴呆后更为明显。混合性痴呆患者的特征性表现为双侧海马容积、内嗅叶皮质容积减小,颞叶萎缩(均P<0.05),但无明显的腔隙性脑梗死(P>0.05)。结论血管性认知障碍患者的影像学异常改变可部分反映不同亚型的病理改变,但对认知障碍程度的反映尚缺乏敏感性,能否联合认知功能评分共同作为血管性认知障碍临床预测指标尚待进一步研究。     

Distraction and target selection in the brain: An fMRI study

To attend successfully, a specification of what is currently relevant is necessary, but not sufficient. Irrelevant stimuli that are also present in the environment must be recognized as such and filtered out at the same time. Using functional magnetic resonance imaging, we showed that posterior brain regions in parietal, occipital and temporal cortex are recruited in order to ignore distracting visual stimuli, while the specification and selection of relevant stimuli is associated with differential activity in frontal cortex and hippocampal areas instead. The results thus suggest that the selection of relevant objects can be anatomically dissociated from the handling of competing irrelevant objects. The dissociation between the increased involvement of parietal and occipital cortex in handling distraction on one hand, and that of frontal cortex in target specification on the other provides neurophysiological support for models of attention that make this functional distinction.     

帕罗西汀治疗阿尔茨海默病的抑郁对照研究

目的：比较帕罗西汀与氯米帕明在阿尔茨海默病(AD)抑郁症状治疗中的疗效和不良反应。方法：帕罗西汀组51例，氯米帕明组44例，均诊断为AD，汉密顿抑郁量表(HAMD，17项)≥18分。比较两组患者治疗后的HAMD减分率，采用副反应量表(TESS)评定不良反应。结果：帕罗西汀组与氯米帕明组总体疗效相当，但帕罗西汀组起效较快，不良反应发生率低。结论：帕罗西汀在AD抑郁症状治疗中具有一定优势，值得临床推广应用。     

fMRI activation during episodic encoding and metacognitive appraisal across the lifespan: risk factors for Alzheimer's disease

In the present study, we used fMRI to examine the influence of age on two other known risk factors for Alzheimer's disease (AD), APOE genotype and parental history of AD (FH status), during episodic encoding (ENC) and metacognitive self-appraisal (SA) paradigms. These paradigms have previously been shown to evoke activity from brain regions that are implicated in AD. First we examined the effect of age across the adult lifespan (age 18-84 years) on cerebral activity in a large sample (n=231) of cognitively healthy individuals. Next we examined a subset (n=155) on whom APOE status and FH status were known. For ENC, we found that increasing age was associated with reduced activity in the ventral temporal lobes and hippocampus. Our analysis of risk factors suggested that FH and age exerted independent effects, but APOE interacted with age such that APOE e4 carriers exhibit age-related increases in activity in the hippocampus. For the metacognitive SA task, increasing age was found to be associated with reduced activity in the medial prefrontal cortex, and increased activity in the mesial temporal lobe, posterior orbital cortex and striatum. Neither AD risk factor significantly modified age-related changes in brain activity during SA. These results suggest that FH and aging are exerting independent effects in both tasks while APOE affected the relationship with age in the hippocampus in one of the two tasks given.     

Posterior Cingulate and Lateral Parietal Gray Matter Volume in Older Adults with Depressive Symptoms

Depressive symptoms occurring late in life are an important risk factor for Alzheimer’s disease (AD). The latest research finds that onset of depressive symptoms in late life may herald the development of AD, not only for amnestic Mild Cognitive Impairment (aMCI) patients, but also for cognitively-normal older adults. Neuroimaging of brain structure, blood flow, and glucose metabolism indicates that depressive symptoms in late life are accompanied by structural and functional changes in limbic brain regions vulnerable to AD. The present cross-sectional study was guided by the hypothesis that compared to their non-depressed counterparts, older adults with mild to moderate depressive symptoms have less volume in limbic structures vulnerable to changes in AD—specifically, cortical midline structures such as anterior cingulate and posterior cingulate cortex as well as mesial temporal regions such as bilateral hippocampi and amygdalae. Consistent with our hypothesis, results of a voxel-based morphometry analysis revealed smaller retrosplenial, posterior cingulate, and precuneus gray matter volumes in depressed individuals relative to healthy controls. Right lateral parietal cortex—another region vulnerable to change in AD—was also smaller in the group with depressive symptoms. Contrary to our hypothesis, no volumetric differences were found in the anterior cingulate cortex or mesial temporal lobe. Results of this study show a relationship between geriatric depressive symptoms and brain volume in regions vulnerable to AD. Follow-up of participants over time will tell if brain changes detected here predict development of AD.     

Reproducibility of human 3D fMRI brain maps acquired during a motor task

This study is an investigation into the reproducibility of brain activation in the sensorimotor cortex obtained with 3D “PRESTO” fMRI on eleven normal subjects. During one session, two series of functional scans were acquired while the subjects performed a finger opposition task (2 Hz). Nine subjects were tested once more on a different day. Each individual motor trial was analyzed separately, with a conservative z_t-based method. Using these results, the agreement between repeated series was examined in a number of ways, comparing the two series within one session, and the two series across sessions. In 28 of the 31 series (90%) significant signal change was found in the contralateral primary sensorimotor cortex (PSM). Overall, 0.20% of all voxels (total about 11,000) in the scanned volume reached significance, and approximately 60% of the significant positive signal changes were located in the PSM (P < 5 x 10^-7 for a chance occurrence). Comparisons within and across sessions yielded similar results: there was a 20–30% overlap of the clusters of activated voxels in the PSM (chance overlap within the PSM: P < 0.01). The mean distance between z_t-weighted centers of mass was 4.0–4.4 mm (chance distance within the PSM: P = 0.033 and 0.058, respectively). No significant difference was found between series in the magnitude of significant signal change. Whereas the number of activated voxels in the PSM was not consistently correlated between series, the ratio of this number over the total number of activated voxels in the scanned volume was significantly correlated (rho = 0.75–0.79, P < 0.05). These results indicate that activation in sensorimotor cortex associated with oppositional finger movement is reliably mapped with 3D PRESTO fMRI. (This article is a US Government work and, as such, is in the public domain in the United States of America.) © 1996 Wiley-Liss, Inc.