轻度认知障碍患者计算能力的fMRI研究

目的 探讨早期诊断A1zheimer病的方法，以及轻度认知障碍(MCI)患者计算能力损害的脑功能定位。方法 对8例MCI患者和9例正常对照使用神经心理测定和功能磁共振(fMRI)检查相结合的方法，比较两组反应时间、正确率和fMRI的脑激活图。结果 患者的反应时间比对照组延长(退位减法P＞0．05，非退值减法P＜0．05一0．01)，正确率降低(P＜0．01-0．001)。脑激活图显示：患者在左侧前额叶外下部，颞叶外侧和顶叶激活减弱(P＜0．05)，而右侧前额叶外下部激活代偿性增强(P＜0．05)。结论MCI患者的计算功能已有损害。计算功能的fMRI与认知神经心理学的联合研究能为早期诊断AD提供有力的参考依据。     

功能磁共振成像观察2型糖尿病患者工作记忆

目的 通过功能磁共振成像技术对2型糖尿病患者的工作记忆进行研究,探讨2型糖尿病患者工作记忆的受损状况.方法 采用1-back组块设计,对16例2型糖尿病患者及13名正常对照受试者,进行词语及客体工作记忆任务的fMRI检查,对反应时间、正确率及脑激活图进行分析.结果 2型糖尿病组患者的正确反应时间、正确率与对照组相比差异无统计学意义(P>0.05).与对照组相比,2型糖尿病组在词语工作记忆时,左侧额叶、左侧顶叶及海马旁回等脑区激活显著减弱(P<0.05),客体工作记忆时,右侧额叶、左侧顶叶及双侧枕叶等脑区激活减弱(P<0.05).结论 2型糖尿病患者存在词语及客体工作记忆损害,经典激活脑区存在损害.     

轻度血管性认知障碍患者计算能力的功能MRI研究

目的利用功能MRI（fMRI）探讨轻度血管性认知障碍（MVCI）患者与正常老年人计算能力的差异,为MVCI患者的诊断提供依据。材料与方法对22例MVCI患者与12例正常老年人进行20以内减法计算时的fMRI,用SPM5处理得出脑激活图,比较正常老年人组和患者组的脑区激活情况和额、顶叶偏侧化现象,用两个独立样本t检验和Mann-Whitney检验比较两组的反应时间和正确率。结果患者的正确率明显低于正常老年组（χ2=18.6,P〈0.001）,反应时间明显延长（t=3.676,P〈0.05）。患者在双侧的顶上、下小叶（顶下小叶为主）,双侧额中回、双侧海马、海马旁回、右侧扣带回后部、双侧颞中回、左侧颞下回、双侧枕叶和双侧小脑激活减弱（P〈0.005）,未见激活增强脑区（P〈0.005）。患者和正常老年组右利手者的额、顶叶在减法计算时均体现左侧偏侧化现象。正常老年组的顶叶左侧偏侧化程度高于额叶,而MVCI组则相反。结论血管性认知障碍患者的计算功能已有不同程度的损害,存在一定的代偿,但仍表现为功能减弱。计算功能的fMRI研究能为诊断MVCI提供参考依据。     

强迫症患者fMRI Stroop试验脑功能异常

目的 应用fMRI观察强迫症(OCD)患者的脑功能异常区域。 方法 OCD患者13例(OCD组),正常对照者15名(正常对照组),按年龄、性别、受教育程度相匹配。对全部受试者行fMRI,刺激采用Stroop任务,运用SPM8软件对两组平均后的脑功能图像的激活区域进行比较分析。 结果 OCD患者需要激活更多脑区(左侧海马旁回、中央旁小叶、丘脑、距状回等)以完成相对简单的色字无干扰任务,激活减低的脑区主要有左侧前扣带回和左侧尾状核。在相对复杂的色字干扰任务时,OCD组并未出现激活高于正常对照组的脑区,激活减低的脑区主要有双侧眶额叶、左侧前扣带回以及左侧尾状核。 结论 OCD患者可能存在眶额叶、前扣带回、尾状核等区域的功能异常,这些脑区功能异常可能在OCD发病机制方面发挥作用。     

轻度认知功能障碍患者记忆损害特点及与氢质子磁共振波谱的相关性研究

目的分析轻度认知功能障碍(MCI)和阿尔茨海默病(AD)患者的记忆损害特点及其与氢质子磁共振波谱(1H-MRS)的关系,探讨记忆功能评定及1H-MRS对MCI和AD的诊断和鉴别诊断的作用。方法用中文听觉词汇学习测验、Rey-Osterrieth复杂图形测验(ROCFT)和韦氏记忆量表中文版的逻辑记忆分测验分别对30例MCI患者、24例AD患者和20例健康对照进行听觉记忆、视觉记忆和逻辑记忆的评分;采用刺激回波序列进行检测,计算双侧额叶和双侧海马的N-乙酰天冬氨酸/肌酸(NAA/Cr)、胆碱/肌酸(Cho/Cr)、肌醇/肌酸(MI/Cr)、N-乙酰天门冬氨酸/肌醇(NAA/MI)等的比值;比较各组间记忆功能评分和各代谢物比值的差别,并进行相关分析。结果 (1)MCI组和AD组的MoCA总分、短时延迟记忆、长时延迟记忆、延时再认、视觉记忆、逻辑记忆评分及AD组的即刻记忆评分均低于对照组(P<0.05);MCI组的MoCA总分、长时延迟记忆、延时再认、视觉记忆、逻辑记忆评分均高于AD组(P<0.05),而即刻记忆、短时延迟记忆评分与AD组差异无统计学意义(P>0.05)。(2)MCI组和AD组左侧额叶、左侧海马的NAA/Cr比值均低于对照组(P<0.05);MCI组和AD组左侧额叶MI/Cr比值高于对照组(P<0.05);MCI组和AD组左侧额叶、双侧海马的NAA/MI比值低于对照组(P<0.05)。与AD组相比,MCI组左侧额叶、左侧海马的NAA/Cr比值升高,差异有统计学意义(P<0.05),左侧额叶、双侧海马的NAA/MI比值升高,差异有统计学意义(P<0.05);Cho/Cr比值在各组间差异无统计学意义(P>0.05)。(3)MCI组和AD组的记忆减退与左侧额叶、左侧海马NAA/Cr和NAA/MI存在正相关(P<0.05)。结论在记忆功能损害方面MCI患者与AD患者具有相似性,且记忆损害与左侧额叶、左侧海马的1H-MRS有相关性,记忆功能评分与1H-MRS结合可作为MCI和AD早期诊断及鉴别诊断的重要工具。     

脑白质疏松轻度认知功能障碍静息态默认网络研究

目的通过静息态功能磁共振成像(rs-fMRI)技术对脑白质疏松(LA)轻度认知障碍(MCI)患者脑默认网络进行分析。方法LA 患者31 例,临床痴呆评分(CDR) 0.5;年龄、性别和受教育程度匹配的正常对照组27 人,CDR 为0。对入组人群进行rs-fMRI 数据采集。使用SPM5 软件进行分析处理,使用fMRI 工具盒对预处理后的数据进行独立成分分析(ICA),组间差异进行双样本t 检验。结果静息状态下,对照组默认网络包括扣带回后部/楔前叶,双侧额叶内侧,双侧颞中回,双侧顶下回、角回,双侧海马。MCI组默认网络激活区域同对照组一致;同对照组相比,MCI患者扣带回前部/左侧额叶内侧、右侧海马旁回/钩回、右侧颞下回、左侧额叶深部白质/尾状核头部激活减低,左侧尾状核/扣带回前部、左侧额叶、左侧颞上回/顶下回的激活升高。结论LA患者静息状态默认网络活动异常,可能与认知障碍的发生有关。     

帕金森病静息状态下纹状体功能连接的fMRI研究

目的应用血氧水平依赖的功能性磁共振成像研究帕金森病(Parkinson's disease,PD)静息状态下功能连接的改变。材料与方法对35例符合PD诊断标准的患者及20名健康者行静息态脑功能性磁共振成像,选双侧纹状体(striaum,STR)为感兴趣区,采用双样本t检验分别比较左侧STR(L-STR)、右侧STR(R-STR)在两组间的脑功能连接的差异。结果 (1)以L-STR为种子点时,PD组右侧前额叶背外侧部、双侧后扣带回皮质、左侧中央前后回、顶下小叶、左侧楔前叶、左侧缘上回等脑区的正连接较正常组减弱(P0.05,Alpha Sim校正),额下回、海马旁回、左侧海马、左侧岛叶正连接增强(P0.05,Alpha Sim校正)。(2)以R-STR为种子点时,PD组右侧前额叶背外侧部、双侧后扣带回皮质等脑区正连接较正常组减弱(P0.05,Alpha Sim校正),右侧舌回、岛叶、海马旁回、双侧海马、左侧丘脑等脑区正连接增强(P0.05,Alpha Sim校正)。结论静息状态下PD患者的脑功能连接网络存在异常。     

汉字情景记忆时皮层定位的fMRI研究

目的探讨用功能磁共振成像(fMRI)检测汉字情景记忆时皮层定位的价值及皮层定位的双侧不对称性.方法 10名健康右利手成人,以高频双字汉字作为刺激任务,行全脑fMRI,确定激活皮层的定位.结果汉字情景记忆时双侧多个脑区有激活,但两侧激活脑区不完全对称,编码加工时主要激活脑区为左侧纹外区和左侧颞叶梭状回,而提取加工时左侧顶叶楔前叶、左侧前额叶背外侧显著激活.结论汉字情景记忆时左右大脑半球激活区存在不对称性,fMRI可对此种功能皮层进行准确定位.     

颞叶癫痫患者rs-fMRI功能连接及其与记忆功能关系的研究

目的:分析颞叶癫痫患者静息态磁共振(rest-f MRI)功能连接及其与记忆功能之间的关系,探讨其脑功能连接的异常及其对记忆障碍诊治的应用价值。方法:对16例颞叶癫痫患者(癫痫组)和与之相匹配的16例健康对照者(对照组)进行静息态脑功能成像和记忆功能测评,比较2组间的脑区差异,分析与记忆功能相关的脑区。结果:癫痫组与对照组比较,海马与全脑功能连接增高的脑区有:左侧旁中央小叶、左侧中央前回、左侧中央后回、左侧前运动皮质和辅助运动区、左侧内侧额叶等;减低的脑区有:右侧小脑、左侧颞上回等。癫痫组海马与全脑功能连接与记忆商呈正相关的脑区有:双侧前扣带回、双侧楔前叶/后扣带回等;呈负相关的脑区有:左侧额下回、左侧中央后回等。结论:左侧旁中央小叶、左侧中央前回、左侧中央后回、左侧前运动皮质和辅助运动区、左侧内侧额叶等脑区可能构成颞叶癫痫患者的癫痫网络,在癫痫发生和发展过程中起重要作用;右侧小脑、左侧颞上回等脑区的功能异常可能与颞叶癫痫患者认知功能损伤有关。双侧前扣带回、双侧楔前叶/后扣带回、左侧额下回、左侧中央后回等脑区与海马之间的功能连接与记忆相关,其对记忆功能具有潜在临床预测价值。     

2型糖尿病患者前扣带回功能连接的静息态fMRI研究

目的：采用静息态f MRI探讨不伴轻度认知功能障碍（MCI）的2型糖尿病（T2DM）患者前扣带回功能连接（FC）的变化特点。方法：纳入56例T2DM及人口学资料相匹配的60例健康被试（HC）,行静息态fMRI检查及神经心理学评估量表,以前扣带回不同亚区为种子点行全脑FC分析,将差异脑区的FC值与临床资料及神经心理学评分行相关性分析。结果：与HC相比,不伴MCI的T2DM患者膝前部前扣带回（pACC BA32）与双侧海马FC值减低,与双侧外侧前额叶及左侧中央前回FC值增高（P均<0.05）。T2DM组pACC(BA32)与左侧海马FC强度与颜色连线测试2(CTT-2)评分呈负相关（P=0.002,r=-0.410）。结论：不伴MCI的T2DM患者pACC(BA32)与双侧海马及双侧外侧前额叶FC紊乱,提示T2DM患者可能存在一种涉及记忆功能的代偿机制。     

正常老年人无意义图形记忆任务的fMRI研究

目的探讨正常老年人进行记忆任务的实验可行性及激活脑区.方法对11例正常老年志愿者进行无意义图形记忆任务的fMRI实验,实验以组块方式设计,包括第一次记忆组、重复记忆组和再认组.实验数据以SPM99作后处理显示激活脑区.结果 10例受试者的记忆任务完成较好,记忆和再认的激活区域主要集中双侧前额叶、双侧海马旁回(左侧为主)、右侧海马、双侧顶叶(主要为顶上小叶和楔前叶).记忆编码时海马的激活集中在海马头部,而提取时海马的激活则集中在海马的体部及尾部.结论老年人进行fMRI认知实验具有可行性,记忆的编码和提取时需要内侧颞叶海马系统的参与,但所倚重的脑区有微小的差别.     

精神分裂症空间工作记忆任务的fMRI研究

目的采用fMRI技术探讨精神分裂症患者空间工作记忆损害的神经机制。方法收集18例精神分裂症患者和18名正常受试者进行空间n-back任务的fMRI扫描。采用SPM 8进行数据预处理和统计分析,单样本t-检验用于分析两组各自脑激活结果,双样本t-检验用于工作记忆相关脑激活的组间比较。采用FDR方法进行多重比较校正。利用SPSS 17.0软件对工作记忆任务中的行为学结果 (正确率和反应时间)进行组间比较。结果与对照组相比,精神分裂症患者空间工作记忆任务反应时间延长(882.00±50.31)ms,正确率下降(83.60±2.90)%(P0.05)。精神分裂症患者在n-back空间工作记忆任务时所激活的脑区分布与对照组基本一致,主要包括双侧前额皮层、颞顶叶皮层及部分基底核团。但组间比较显示精神分裂症患者多个脑区激活强度及范围明显增加,包括双侧前额皮层背外侧、双侧后顶叶皮层、右侧中央前回、左侧颞中回、右扣带回和双侧小脑(FDR校正,P0.05)。结论执行空间工作记忆任务时精神分裂症患者脑区激活增加,但行为学表现下降,提示患者脑区活动效率低下,可能是工作记忆能力损害的神经基础。     

阿尔茨海默病和轻度认知障碍磁共振动脉自旋标记脑灌注与神经心理学量表相关性研究

目的探讨阿尔茨海默病(alzheimer disease,AD)和轻度认知障碍(mild cognitive impairment,MCI)脑血流灌注改变、认知功能损害,以及二者之间的关系。材料与方法 30例经首都医科大学宣武医院神经内科记忆障碍门诊诊断的AD患者(AD组)、30例MCI患者(MCI组)、30例与之年龄、性别和受教育程度相匹配的正常老年人作为对照组(NC组)。采用2D连续性动脉自旋标记(arterial spin labeling,ASL)技术半定量测量局部脑血流和神经心理学量表联合评估AD患者脑灌注和认知状况,分析AD组、MCI组及NC组的认知状态、脑灌注特点,以及认知功能与脑灌注的相关性。结果 (1)3组被试年龄、性别、受教育年限比较,差异无统计学意义(P0.05),3组简易精神状态量表(mini-mental state examination,MMSE)评分、蒙特利尔认知评估量表(montreal cognitive assessment,Mo CA)评分两两比较差异均有统计学意义(P0.05)。(2)AD组和MCI组在双颞叶、双顶叶、双放射冠脑白质等信号强度不同程度降低,而且3组被试中两两比较差异均具有统计学意义。(3)对AD组、MCI组患者脑灌注多部位信号强度与MMSE及MOCA评分进行双因素相关分析发现,双颞叶、双顶叶信号强度与MMSE和Mo CA评分成正相关。结论 (1)应用ASL技术可以清晰显示AD患者和MCI的脑灌注减低区,与NC比较差异有统计学意义,可能有助于AD及MCI的早期评价。(2)MMSE和Mo CA评分与MRI的ASL脑灌注之间有良好的相关性,二者结合可提高判定AD和MCI的准确性。     

The effect of word concreteness on recognition memory

Concrete words that are readily imagined are better remembered than abstract words. Theoretical explanations for this effect either claim a dual coding of concrete words in the form of both a verbal and a sensory code (dual-coding theory), or a more accessible semantic network for concrete words than for abstract words (context-availability theory). However, the neural mechanisms of improved memory for concrete versus abstract words are poorly understood. Here, we investigated the processing of concrete and abstract words during encoding and retrieval in a recognition memory task using event-related functional magnetic resonance imaging (fMRI). As predicted, memory performance was significantly better for concrete words than for abstract words. Abstract words elicited stronger activations of the left inferior frontal cortex both during encoding and recognition than did concrete words. Stronger activation of this area was also associated with successful encoding for both abstract and concrete words. Concrete words elicited stronger activations bilaterally in the posterior inferior parietal lobe during recognition. The left parietal activation was associated with correct identification of old stimuli. The anterior precuneus, left cerebellar hemisphere and the posterior and anterior cingulate cortex showed activations both for successful recognition of concrete words and for online processing of concrete words during encoding. Additionally, we observed a correlation across subjects between brain activity in the left anterior fusiform gyrus and hippocampus during recognition of learned words and the strength of the concreteness effect. These findings support the idea of specific brain processes for concrete words, which are reactivated during successful recognition.     

屈光参差性弱视患者立体视觉相关皮层的fMRI评价

目的评价屈光参差性弱视患者立体视觉相关皮层的功能状况,讨论立体视觉功能障碍的可能神经机制。方法屈光参差性弱视患者11例,正常对照组10例,对两组进行组块设计的fMRI实验。刺激内容为计算机生成的随机点平面图和立体图,要求被试通过红蓝滤光镜片观察图案,识别平面或立体图。采用SPM2进行图像后处理,采用随机效应组分析方法获得弱视组及对照组在平面刺激和立体刺激下的平均图,并采用组间分析获得两组在立体视觉刺激下的差异图。结果两种图形刺激下,两组均见双侧枕叶激活;立体图刺激下对照组还可见双侧顶叶激活,弱视组仅见右顶叶激活。立体图形刺激下,对照组减患者组的差异图显示右侧枕叶和双侧顶叶后部激活。结论双侧顶叶后部激活下降或消失是屈光参差性弱视患者立体视觉障碍的一种神经机制。     

Changes in brain activation associated with use of a memory strategy: a functional MRI study

It has been confirmed that some kinds of what are called memory strategies dramatically improve the performance of memory recall. However, there has been no direct research to examine changes in brain activity associated with the use of the method of loci within individuals. In the present study, using fMRI, we compared brain activations before and after instruction in the method of loci during both the encoding and recall phases. The resulting behavioral data showed that the use of the method of loci significantly increased scores for memory recall. The imaging data showed that encoding after instruction in the method of loci, relative to encoding before it, was associated with signal increases in the right inferior frontal gyrus, bilateral middle frontal gyrus, left fusiform gyrus, and bilateral lingual gyrus/posterior cingulate gyrus. Comparison of recall after instruction in the method of loci with that before it showed significant activation in the left parahippocampal gyrus/retrosplenial cortex/cingulate gyrus/lingual gyrus, left precuneus, left fusiform gyrus, and right lingual gyrus/cingulate gyrus. The present study demonstrated the changes in brain activation pattern associated with the use of the method of loci; left fusiform and lingual activity was associated with both the encoding and recall phases, bilateral prefrontal activity with the encoding phase, and activity of the posterior part of the parahippocampal gyrus, retrosplenial cortex, and precuneus with the recall phase. These findings suggest that brain networks mediating episodic encoding and retrieval vary with how individuals encode the same stimuli.     

Prolonged reaction time to a verbal working memory task predicts increased power of posterior parietal cortical activation

We used multislice functional magnetic resonance imaging (fMRI) to investigate the association between behavioral and neurophysiological measures of working memory task performance in 20 right-handed male healthy volunteers. Images were acquired over a 5-min period at 1.5 Tesla. We used a periodic design, alternating 30-s blocks of the "n-back" working memory task with 30-s blocks of a sensorimotor control task to activate verbal working memory systems. The power of functional response to the task was estimated by sinusoidal regression at each voxel. The relationship between power of fMRI response and mean reaction time over all 11 working memory trials was explored by multiple regression, with age and mean reaction time to the control task as covariates, at voxel and regional levels of analysis. All subjects were able to perform the n-back task accurately. A spatially distributed network was activated, including dorsolateral prefrontal cortex, inferior frontal gyrus, lateral premotor cortex, and supplementary motor area (SMA) in the frontal lobes. More posteriorly, there were major foci of activation in parietal and occipitoparietal cortex, precuneus, lingual, and fusiform gyri of the ventral occipital lobe, inferior temporal gyrus, and cerebellum. The power of functional response was positively correlated with reaction time in bilateral posterior parietal cortex (Talairach coordinates in x, y, z (mm) 35, -44, 37 and -32, -56, 42), indicating that subjects who found the task difficult, and responded with a slower reaction time, tended to activate these regions more powerfully. One interpretation of this regionally specific relationship between prolonged reaction time and increased power of posterior parietal activation is consistent with prior studies identifying similar areas of parietal cortex as the site of the phonological storage function in verbal working memory.     

Differential components of sentence comprehension: beyond single word reading and memory

A number of studies have used functional neuroimaging to examine the neural mechanisms of sentence comprehension; however, few fMRI studies have examined activation patterns associated with sentence comprehension after accounting for activation attributable to single-word-level tasks important for sentence comprehension. To investigate the patterns of activation associated with sentence comprehension after controlling for single word reading and maintaining single words in memory, 20 unimpaired adult readers completed a block design paradigm which included sentence comprehension, single word reading, and short-term memory (for words) tasks. Results indicated that, regardless of the aspect of sentence comprehension being controlled for, activation was observed in bilateral temporal lobes (left > right) as well as bilateral occipital lobes and middle frontal gyri. Additional findings showed that bilateral superior parietal lobe activation was greatest for short-term memory for words, while left anterior inferior frontal gyri activation (centered around Brodmann's area 47) was greatest for single word reading. Results suggest that temporal cortex (left > right) is a core region important for sentence comprehension beyond the short-term memory and semantic requirements inherent in processing sentences.