慢性失眠患者汉字工作记忆的功能磁共振研究

目的探讨慢性失眠患者汉字任务下脑激活区改变。方法对40例慢性失眠患者和50例正常对照组进行汉字工作记忆功能磁共振扫描。结果慢性失眠组与正常组脑激活区存在差异:慢性失眠组编码期枕叶、右前额和右边缘叶激活增强;保持期左前额激活下降;提取期激活增强区为右枕叶,激活下降区为左尾状核和右侧丘脑。结论慢性失眠患者在文字记忆任务编码期及提取期均出现了右脑皮层的代偿激活,保持期出现了左前额激活下降,提取期出现了皮层下区域激活的下降,提示慢性失眠在文字记忆处理过程出现了相关脑区的损害和异常激活。     

慢性失眠患者数字工作记忆的功能磁共振研究

目的 探讨慢性失眠患者数字工作记忆神经网络连接的改变.方法 采用组块设计方法,分别对40例慢性失眠患者(失眠组)及50例正常睡眠者(对照组)进行数字工作记忆状态下功能磁共振扫描,比较两组受试者在数字工作记忆中反应时间及正确率以及编码、维持、提取阶段脑区激活强度的改变.结果 失眠组与对照组数字工作记忆正确率的比较差异无统计学意义(P＞0.05),失眠组反应时间明显增加,差异有统计学意义(P＜0.01).慢性失眠患者在数字工作记忆编码期激活强度增强的脑区为左侧壳核、豆状核、顶下小叶及右侧尾状核、右枕叶;维持期激活强度增强的脑区为右侧额叶,左侧额叶及额叶内侧面,而左侧额上回激活强度有所下降;提取期激活强度增强的脑区为右额下回及右顶下缘角回,而激活轻度下降的脑区则有左内侧额上回、左岛叶、左后扣带回、左颞上回、左额上回及右颞叶、右后扣带回.结论 慢性失眠患者在数字工作记忆的各阶段,脑区激活强度较健康人有所改变:大脑皮质和皮质下结构广泛受损,即其神经网络连接发生明显改变.     

抑郁症患者识别负性表情的脑磁源性影像动态变化

目的 利用磁源性影像技术以及表情事件相关识别实验范式探讨抑郁症患者识别负性动态表情的神经网络磁源性影像动态变化的特点.方法 利用脑磁图检测12例抑郁症患者(患者组)及12名年龄、性别、受教育年限近似匹配的健康对照者(对照组)识别负性动态表情视频时的脑部反应.设P＜0.01时,差异均具有统计学意义.结果 与对照组相比,患者组识别负性面部表情时,活动异常主要出现在双侧钩回、双侧颞上回、右额中回、右杏仁核、右颞回下、左梭状回、左枕下回、右海马旁回、左枕舌回、双侧楔前叶、左楔叶等脑区,这些脑区组成的神经网络在识别负性动态表情过程有相应脑区激活异常.结论 抑郁症患者识别负性表情的功能网络的脑磁源性影像动态变化特点与正常人比较差异有统计学意义.     

血管性认知功能损害患者工作记忆和计算能力的fMRI研究

目的研究血管性认知功能损害(vascular cognitive impairment,VCI)患者在执行工作记忆和计算任务时,其功能磁共振(functional magnetic resonance imaging,fMRI)的信号激活脑区强度同正常人进行比较是否存在区别,明确VCI患者脑功能区信号变化特点,为VCI提供影像学诊断依据。方法采用简明精神状态检查(mini-mental state examination,MMSE)进行智能评定。利用功能磁共振成像技术,对25例VCI患者和15例对照组患者进行倒背数字作业,计算能力测验,对脑激活功能区进行分析,利用SPM2软件对图像数据进行处理。结果 VCI患者倒背数字作业时,双侧额中回、海马及颞上回激活脑区像素值显著减少(P<0.05);在计算能力测试方面,双侧额中回、海马、颞上回以及左侧角回、缘上回激活脑区像素值也显著减少(P<0.05)。结论在执行工作记忆和计算任务时,VCI患者存在特定激活脑区信号的减弱,通过对fMRI信号的侦测,可以为VCI的早期诊断提供影像学依据。     

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.     

健康人倒背数字作业的脑功能磁共振成像研究

目的　利用功能磁共振成像(functionalmagneticresonanceimaging ,fMRI)技术探讨倒背数字作业认知功能的脑功能定位。方法　1 8名健康志愿者完成以倒背数字作业(backwarddigitspantask ,BDST)作为刺激模式、采用组块设计(block)的fMRI检查,经工作站处理后获功能图像。结果　健康志愿者的左侧额上回、额中回、额下回、中央前回、顶上小叶、缘上回、颞下回、枕颞外侧回及右侧额中回等脑区均有明显激活。结论　左侧额叶腹外侧及左侧项叶后下部可能参与工作记忆对语言材料激活信息的保持,而双侧额叶背外侧可能参与工作记忆对语言材料激活信息的执行控制。     

年轻人与老年人简单乘法运算之功能磁共振成像研究

目的应用fMRI技术探讨中国青年和老年人群在简单运算任务下脑激活模式及其与行为学之间的关系。方法分别对青年组(19例)和老年组(20例)健康志愿者进行对照任务和简单运算任务下的fMRI检查。结果两组受试者受教育程度(P=0.125)、智力水平(P=0.921),以及完成对照任务(P=0.142)和简单乘法运算任务(P=0.880)之正确率差异无统计学意义,但老年组受试者完成对照任务(P=0.000)和简单乘法运算任务(P=0.005)反应时间明显延长。青年组受试者在任务刺激下可激活右侧缘上回并向顶内沟和颞中上回后部延伸,中央前回和运动前区、前额叶,左侧缘上回并向颞上回后部和角回延伸,顶内沟区域、颞中下回,内侧后扣带回、楔前叶、辅助运动区、海马沟、海马旁回及前额叶内侧;老年组受试者则分别激活右侧缘上回和顶下区域并向颞中上回后部延伸,中央前回和运动前区、前额叶,左侧缘上回和角回并向顶下延伸,中央前回和运动前区、岛叶及前额叶,内侧后扣带回和中央旁小叶、前扣带回及前额叶内侧;两组受试者共激活脑区包括顶下区域、楔前叶、中央前后回和额顶叶网络,以及颞叶、海马旁回、钩回、屏状核和后扣带回等皮质下结构。结论数学事实提取相关网络的主要成分受年龄影响较小,老年人群的任务激活脑区主要向任务相关顶区集中。     

矿难后急性重性创伤后应激障碍症状激发和创伤有关短期记忆提取的功能性磁共振成像研究

目的 探讨急性重性创伤后应激障碍(post traumatic stress disorder,PTSD)患者的脑功能及执行记忆功能时的脑反应.方法 采用功能磁共振成像技术,对经历矿难的10例急性重性PTSD患者(PTSD组)和7例非PTSD对照(非PTSD组)执行症状激发任务,并首次采用1项创伤有关的短期记忆提取任务进行记忆功能的测定.结果 症状激发试验中,PTSD组负性图片相比中性图片,左侧后扣带回、双侧尾状核和右侧丘脑等脑区激活增强,右侧扣带回和双侧额中回激活下降;PTSD组相比非PTSD组,右侧前扣带回、左侧额下回、双侧额中回及双侧颞中回等脑区激活下降,左侧海马旁回激活增高.短期记忆提取任务中,PTSD组负性图片相比中性图片,右侧后扣带回和双侧海马存在明显激活;PTSD组相比非PTSD组,右侧额下回、右侧额中回、左侧枕中回等脑区激活下降.记忆提取任务相比症状激发任务,PTSD组右侧海马旁回激活下降.结论 急性重性PTSD患者在急性期已存在部分脑区激活的下降以及记忆功能的减退.     

基于低频振幅方法的连枷臂综合征患者静息态功能磁共振成像研究

目的 采用静息态功能磁共振成像(RS-fMRI)低频振幅(ALFF)分析法,探讨连枷臂综合征(Flail arm syndrome,FAS)患者基线脑活动变化及意义。方法 对10名确诊的连枷臂综合征患者(连枷臂组)和10名与之年龄、性别、教育程度相匹配的正常成年人对照者(对照组)进行静息态磁共振成像扫描,应用ALFF分析法计算并比较两组受试者全脑的ALFF值的差异,并进一步分析其与临床症状严重程度的相关性。结果 静息态下,与正常对照组相比较,FAS组在双侧楔前叶、左侧楔叶、后扣带回、枕上回、颞中回、枕中回、角回、顶下缘角回脑区均出现ALFF值的低于正常对照组,但没有发现FAS组ALFF增高的脑区。ALFF明显减低的脑区的ALFF值与ALS功能分级量(ALSFRS-R)总分无相关性。结论 静息态下主要在双侧楔前叶、左侧楔叶、后扣带回、枕上回、颞中回、枕中回、角回、顶下缘角回脑区的脑功能活动异常,这些脑区ALFF改变可能与FAS的病理机制有关,但与FAS疾病严重程度无关。     

脑功能活动水平对抑郁症病情的影响

目的探讨脑功能活动水平对抑郁症病情的影响。方法选取我院2015年1月~2016年12月收治的抑郁症患者86例为研究对象。采用汉密尔顿抑郁量表(HAMD)评估患者抑郁状况。所有患者接受功能磁共振成像检测。结果 86例患者HAMD评分(23.5±4.3)分。HAMD评分与ReHo值呈正相关的脑区包括右侧颞下回(BA22)、右侧楔叶(BA18)、左侧上前扣带皮层(BA36)、左侧楔前叶(BA9)、左侧下后扣带皮层(BA25)、左侧上后扣带皮层(BA32)和左侧额极区(BA12)。HAMD评分与ReHo值呈负相关的脑区包括左侧中央后回(BA20)、右侧中央前回(BA38)、右侧背外侧前额叶(BA11)和右侧颞上回(BA41)。结论抑郁症患者多个脑区ReHo值存在异常,静息态下脑功能损害主要集中在默认网络和边缘系统等多个脑区。ReHo分析可反映抑郁症患者静息态下脑功能变化,具备成为抑郁症严重程度评估的有效工具。     

Correlations between clinical symptoms, working memory functions and structural brain abnormalities in men with schizophrenia

Thirteen male patients with schizophrenia and thirteen male normal control subjects were compared by magnetic resonance imaging (MRI) on volumes of the straight gyrus (SG), anterior cingulate gyrus, middle frontal gyrus, hippocampus, third ventricle, cavum septi pellucidi, total brain volume and intracranial volume. In addition, neuropsychological tasks were used to measure working memory and executive functions. Healthy volunteers and schizophrenic patients showed no significant differences in mean values for volumes of regions of interests. In the case of the SG, we found a significant difference in laterality: the tendency toward left dominance in healthy volunteers changed to significant right dominance in patients. The schizophrenic patients showed lower performance in working memory tasks, and strongly significant group differences were observed in measures of neurological signs assessed by the Neurological Evaluation Scale (NES). Negative symptoms correlated with the level of spatial working memory and executive functions. Negative symptoms also correlated with the volume of the right hippocampus, while the rate of anhedonia negatively correlated with the relative volume of the left SG.     

Neocortical system abnormalities in autism: an fMRI study of spatial working memory

OBJECTIVE: To test the hypothesis that deficits in spatial working memory in autism are due to abnormalities in prefrontal circuitry. METHODS: Functional MRI (fMRI) at 3 T was performed in 11 rigorously diagnosed non-mentally retarded autistic and six healthy volunteers while they performed an oculomotor spatial working memory task and a visually guided saccade task. RESULTS: Autistic subjects demonstrated significantly less task-related activation in dorsolateral prefrontal cortex (Brodmann area [BA] 9/46) and posterior cingulate cortex (BA 23) in comparison with healthy subjects during a spatial working memory task. In contrast, activation of autistic individuals was not reduced in other regions comprising the neural circuitry for spatial working memory including the cortical eye fields, anterior cingulate cortex, insula, basal ganglia, thalamus, and lateral cerebellum. Autistic subjects also did not demonstrate reduced activation in any brain regions while performing visually guided saccades. CONCLUSION: Impairments in executive cognitive processes in autism may be subserved by abnormalities in neocortical circuitry as evidenced by decreased activation in prefrontal and posterior cingulate circuitry during a spatial working memory task.     

Towards a functional neuroanatomy of self processing: effects of faces and words

We studied the neural correlates of self vs. non-self judgements using functional magnetic resonance imaging (fMRI). Individually tailored faces and personality trait words were used as stimuli in three experiments (exp.). In the first two experiments, brain activation was measured while subjects viewed morphed versions of either their own (self face exp.) or their partner's face (partner's face exp.), alternating in blocks with presentation of an unknown face. In the self face exp. right limbic areas (hippocampal formation, insula, anterior cingulate), the right middle temporal lobe, left inferior parietal and left prefrontal regions showed signal changes. In the partner's face exp., only the right insula was activated. In the third exp., subjects made decisions about psychological trait adjectives previously categorized as describing their own attributes. Activation was present in the precuneus, the left parietal lobe, left insula/inferior frontal gyrus and the left anterior cingulate. A reaction time advantage was present when subjects responded to self-relevant words. The main area with signal changes during self-reference processing, regardless of the type of stimulus, was the left fusiform gyrus. The self-relevant stimuli engaged to a differential extent long term and working memory, semantic and emotional processes. We suggest that regions activated by these stimuli are engaged in self-processing.     

fMRI及DTI技术在成人工作记忆研究的初步探索

目的：联合应用脑功能磁共振成像（BOLD—fMRI）和弥散张量成像（DTI）两种磁共振技术,探索工作记忆功能激活部位与叶间白质纤维束的关系。方法：健康志愿者16名,以步进式视觉累加试验作为刺激模式,扫描获得fMRI激活图及各向异性（FA）图。将两者叠加,选取双侧额顶叶白质兴趣区测量其部分FA值。结果：①额顶叶皮质为工作记忆功能最主要的激活区;②脑的激活像素几乎均位于FA程度低的区域（P〈0．01）;③左额顶间白质FA值较对侧高（P〈0．02）。结论：联合应用fMRI和DTI技术提示成人工作记忆功能与额顶叶白质纤维髓鞘化程度密切相关。     

Relationships between years of education,regional grey matter volumes,and working memory-related brain activity in healthy older adults

The aim of this study was to examine the relationships between educational attainment, regional grey matter volume, and functional working memory-related brain activation in older adults. The final sample included 32 healthy older adults with 8 to 22 years of education. Structural magnetic resonance imaging (MRI) was used to measure regional volume and functional MRI was used to measure activation associated with performing an n-back task. A positive correlation was found between years of education and cortical grey matter volume in the right medial and middle frontal gyri, in the middle and posterior cingulate gyri, and in the right inferior parietal lobule. The education by age interaction was significant for cortical grey matter volume in the left middle frontal gyrus and in the right medial cingulate gyrus. In this region, the volume loss related to age was larger in the low than high-education group. The education by age interaction was also significant for task-related activity in the left superior, middle and medial frontal gyri due to the fact that activation increased with age in those with higher education. No correlation was found between regions that are structurally related with education and those that are functionally related with education and age. The data suggest a protective effect of education on cortical volume. Furthermore, the brain regions involved in the working memory network are getting more activated with age in those with higher educational attainment.     

Color Stroop and negative priming in schizophrenia: An fMRI study

Disturbances in selective attention represent a core characteristic of schizophrenia, whose neural underpinnings have yet to be fully elucidated. Consequently, we recorded brain activation using functional magnetic resonance imaging (fMRI) while 15 patients with schizophrenia and 15 age-matched controls performed a well-established measure of selective attention—the color Stroop negative priming task. We focused on two aspects of performance: overriding pre-potent responses (Stroop effect) and inhibition of prior negatively primed trials (negative priming effect). Behaviorally, controls demonstrated both significant Stroop and negative priming effects, while schizophrenic subjects only showed the Stroop effect. For the Stroop effect, fMRI indicated significantly greater activation in frontal regions–medial frontal gyrus/anterior cingulate gyrus and middle frontal gyrus for controls–but greater activation in medial parietal regions (posterior cingulate gyrus/precuneus) for patients. Negative priming elicited significant activation in right dorsolateral prefrontal cortex for both groups, but also in left dorsolateral prefrontal cortex for patients. These different patterns of fMRI activation may reflect faulty interaction in schizophrenia within networks of brain regions that are vital to selective attention.     

Morphometry and connectivity of the fronto-parietal verbal working memory network in development

Two distinctly different maturational processes – cortical thinning and white matter maturation – take place in the brain as we mature from late childhood to adulthood. To what extent does each contribute to the development of complex cognitive functions like working memory? The independent and joint contributions of cortical thickness of regions of the left fronto-parietal network and the diffusion characteristics of the connecting pathway of the left superior longitudinal fasciculus (SLF) in accounting for verbal working memory performance were investigated, using a predefined regions of interest-approach. 108 healthy participants aged 8–19 years underwent MRI, including anatomical and diffusion tensor imaging (DTI), as well as cognitive testing using a digit span task. Radial diffusivity of the SLF, as well as cortical thickness of supramarginal gyrus and rostral middle frontal cortex, were negatively related to digit span forwards performance, independently of age. Radial diffusivity of the SLF was also negatively related to digit span backwards. A multi-modal analysis showed that cortical thickness and SLF microstructure were complementary in explaining working memory span. Furthermore, SLF microstructure and cortical thickness had different impact on working memory performance during the developmental period, suggesting a complex developmental interplay. The results indicate that cortical and white matter maturation each play unique roles in the development of working memory.     

Neural activity associated with episodic memory for emotional context

To address the question of which brain regions subserve retrieval of emotionally-valenced memories, we used event-related fMRI to index neural activity during the incidental retrieval of emotional and non-emotional contextual information. At study, emotionally neutral words were presented in the context of sentences that were either negatively, neutrally or positively valenced. At test, fMRI data were obtained while participants discriminated between studied and unstudied words. Recognition of words presented in emotionally negative relative to emotionally neutral contexts was associated with enhanced activity in right dorsolateral prefrontal cortex, left amygdala and hippocampus, right lingual gyrus and posterior cingulate cortex. Recognition of words from positive relative to neutral contexts was associated with increased activity in bilateral prefrontal and orbitofrontal cortices, and left anterior temporal lobe. These findings suggest that neural activity mediating episodic retrieval of contextual information and its subsequent processing is modulated by emotion in at least two ways. First, there is enhancement of activity in networks supporting episodic retrieval of neutral information. Second, regions known to be activated when emotional information is encountered in the environment are also active when emotional information is retrieved from memory.     

Abnormal baseline brain activity in low-grade hepatic encephalopathy: a resting-state fMRI study

Resting-state functional magnetic resonance imaging (fMRI) has been used to detect the alterations of spontaneous neuronal activity in various neuropsychiatric diseases, but rarely in low-grade hepatic encephalopathy (HE), a common neuropsychiatric complication of liver cirrhosis. We conducted a resting-state fMRI in 19 healthy controls, 18 cirrhotic patients without HE, and 22 cirrhotic patients with low-grade HE. The amplitude of low-frequency fluctuations (ALFF) of fMRI signal was computed to measure the spontaneous neuronal activity. Several regions showing significant ALFF differences among three groups were the precuneus, occipital lobe, left frontal lobe and anterior/middle cingulate cortex, and left cerebellum posterior lobe. Compared to controls or patients without HE, patients with low-grade HE showed decreased ALFF in the precuneus and adjacent cuneus, visual cortex, and left cerebellum posterior lobe. Compared to controls, patients with low-grade HE showed higher ALFF in both cortical and subcortical regions, including the right middle cingulate gyrus, and left anterior/middle cingulate gyrus, inferior frontal gyrus, insula lobe, parahippocampal gyrus, middle temporal gyrus and lentiform nucleus; compared to patients without HE, patients with low-grade HE showed higher ALFF in the left medial frontal gyrus and anterior cingulate gyrus, bilateral superior frontal gyrus, and right middle frontal gyrus. Moreover, correlations between ALFF changes and poor neurocognitive performances were found in patients with low-grade HE. These results suggested the existence of aberrant brain activity at the baseline state in low-grade HE, which may be implicated in the neurological pathophysiology underlying HE.