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.     

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。     

正常人汉字工作记忆功能磁共振脑激活区改变的研究

目的探讨正常人汉字任务下脑激活区的改变。方法对40例正常人进行汉字工作记忆功能磁共振扫描。结果汉字工作记忆任务下,编码、保持及提取期均有额叶、楔前叶、楔叶、边缘叶及扣带回的正向激活,且有侧脑室及脑脊液在编码及保持期的正向激活和在提取期的负向激活。除共同激活脑区外,编码期所有激活脑区均为正向激活,保持期正向激活脑区有中央前回、杏仁核、上后扣带皮层(BA 31),负向激活脑区有颞中回、顶叶、角回,提取期正向激活脑区有尾状核。结论汉字任务下,脑激活区的改变除皮层及皮层下结构,还有侧脑室及脑脊液的激活。     

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。     

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.     

首发抑郁症患者字母工作记忆fMRI研究

目的探讨首发抑郁症患者字母工作记忆的脑激活特征。方法12例首发抑郁症患者与12名健康对照配对进行字母工作记忆任务的功能磁共振成像(fMRI)。以AFNI软件对fMRI数据进行定位与定量分析。结果①两组任务执行正确率均大于75%,患者组字母工作记忆2-back任务正确率低于对照组[(0.79±0.04)%vs(0.83±0.03)%,t=4.69,P<0.05];②两组字母工作记忆激活的感兴趣脑区(ROI)均为左侧Broca区BA44/45、双侧前额叶腹侧BA9/46、顶叶后部BA7/40、前运动区BA6及辅助运动区(SMA)BA6/8(P<0.05);③患者组在右侧与左侧BA9/46、右侧与左侧BA6及左侧Broca区的激活强度分别为:1.38%、1.69%、1.21%、1.32%及0.52%,低于对照组的2.42%、3.53%、2.95%、3.51%及1.62%(P<0.05)。结论首发抑郁症患者存在字母工作记忆损害,而语音环路的双侧BA9/46、BA6与左侧Broca区激活减弱可能为其病理机制之一。     

轻度认知功能障碍患者的执行功能和工作记忆研究

目的 了解轻度认知功能障碍(MO)患者的执行功能和工作记忆是否损害及工作记忆损害特点,探讨执行功能对MCI患者的日常生活活动能力(ADL)的影响.方法 运用神经心理学测试的方法对30例MCI患者进行执行功能、工作记忆及其他认知功能检查,同时进行ADL评定,另外选择30名健康老人作为对照组.结果 MCI组的执行功能和工作记忆成绩(分)显著低于对照组,其中数字颜色连线干扰(130.8±58.2)、数字颜色连线B(210.2±81.8)、词汇流畅性测试(8.9±5.4)、视觉客体工作记忆(0.73±0.12)和数字广度(3.4±0.9),除视觉空间工作记忆外,与对照组比较(52.0±13.5、121.0±33.4、16.4±5.4、0.85±9.18、4.2±1.1)差异均有统计学意义(t=7.108、5.159、-4.879、-4.351、-2.544,均P<0.01或P<0.05).用多元逐步回归方法分析执行功能对ADL的影响,结果 客体工作记忆、空间工作记忆和词汇流畅性与ADL的影响相关,而客体工作记忆与ADL的影响有显著相关性(β=-0.720,t=-3.571,P=0.001).结论 MCI患者具有明显的执行功能障碍和工作记忆损害,工作记忆与MCI患者的ADL有良好相关性,而且视觉客体工作记忆与MCI患者的ADL测查具有显著相关性,因此MCI患者的执行功能障碍可能是导致其ADL下降和客体工作记忆损害的主要因素.     

精神分裂症患者工作记忆与执行功能表现关系的功能磁共振研究

目的 探讨偏执型精神分裂症患者2-back任务状态下的脑区激活特点及其与执行功能表现的关系.方法 采用参数性2-bsck任务,分别检测14例偏执型精神分裂症患者和16名正常志愿者的脑激活情况.应用SPM2软件进行图像数据处理,其中统计阈值P=0.005(未校正),对行为学表现采用SPSS13.0进行统计分析.结果在2-back任务时,患者组额顶叶正激活及负激活脑区的强度均低于正常对照组,但未见较正常对照组激活增强的脑区.行为学表现:患者组和对照组2-back任务的反应时间差异无统计学意义[(935.78±173.18)ms vs(845.16±101.07)ms,P>0.05],但患者组的反应正确率低于对照组[(78.30±8.76)%vs(89.89±8.05)%,P=0.01];患者组低于对照组的正激活脑区与患者组的反应正确率呈正相关(r为0.41～0.63),但只有右顶上小叶和右尾状核分别与正确率之间的相关有统计学意义(P<0.05);低于对照组的负激活脑区与患者组的反应正确率呈负相关但无统计学意义(r为-0.17～-0.35,P均大于0.05).结论 偏执型精神分裂症患者额顶叶正激活减弱与执行功能表现差有关;负激活减弱可能与执行功能表现差、注意转换效率低下或无效有关.     

功能磁共振成像研究睡眠剥夺36小时对健康男性工作记忆的影响

目的 利用功能磁共振成像(functional magnetic resonance imaging,fMRI)技术研究睡眠剥夺36 h对健康男性工作记忆的影响及可能机制.方法 10名健康男性受试者连续36 h睡眠剥夺,睡眠剥夺前后分别接受工作记忆任务测试,同时进行fMRI扫描.fMRI扫描采用2项工作记忆任务,收集获得的行为学结果和fMRI图像,用SPM2软件进行图像分析.比较睡眠剥夺前后工作记忆任务测试及fMRI扫描结果.结果 剥夺后LTR任务的反应时间为(866±102)ms,比剥夺前[(754±91)ms]明显延长(t=2.59,P<0.01),准确率为84.78%±8.71%,比剥夺前(95.31%±3.56%)明显降低(t=3.52,P<0.01);剥夺后PLUS任务的反应时间为(848±94)ms,比剥夺前[(756±79),ms]明显延长(t=2.37,P<0.05),准确率为84.22%±9.66%,比剥夺前(95.70%±4.72%)明显降低(t=3.38,P<0.01);剥夺前在额顶叶、前扣带回和丘脑等工作记忆相关性脑区被激活.PLUS任务较LTR任务激活脑区范围更广,强度更显著.剥夺后顶叶激活降低,前额叶和丘脑的激活增强.结论 睡眠剥夺能够导致工作记忆能力受损.fMRI显示睡眠剥夺后完成工作记忆任务时,在相应脑区顶叶激活降低,前额叶和丘脑激活增强,这可能是睡眠剥夺导致认知功能损害的机制之一.     

运动性失语患者不同疗效的功能MRI研究

目的探讨运动性失语患者不同疗效的脑区激活特点。方法选取处于同一基线水平的运动性失语患者,均进行1个月常规失语症康复训练。根据评价结果分为疗效较好组和疗效较差组,与正常人分别进行图片命名任务的fMRI检查,分析各组激活脑区的差异:结果正常人组双侧岛叶(BA13)、左侧Broca区及其右侧镜像区(BA45)等区域有明显激活,激活区域以左侧半球为多,有明显左侧偏侧性;疗效较差组整体激活较正常人组明显下降,右侧大脑脑区有过多激活,左右间差距较正常人组缩小;疗效较好组则激活区域左侧偏侧性明显,左右间差距较疗效较差组增大,无右侧大脑脑区过多激活。结论语言功能有明显左侧偏侧性,运动性失语症患者语言功能恢复与左侧半球未受损的功能相关。     

Postconcussion syndrome after minor head injury: Brain activation of working memory and attention

After minor head injury (MHI) postconcussive symptoms (PCS) such as memory and attention deficits frequently occur. It has been hypothesised that PCS are caused by microstructural damage to the brain due to shearing injury, which is not detectable with conventional imaging, and may be responsible for a functional deficit. The purpose of this study was to correlate functional magnetic resonance imaging brain activation of working memory and selective attention with PCS. 21 MHI patients and 12 healthy controls were scanned at 3T. Stimulation paradigms were the n‐back and Counting Stroop tasks to engage working memory and selective attention, respectively. Functional data analysis consisted of random effects group analyses, correlating brain activation patterns with the severity of PCS as evaluated with the Rivermead postconcussion symptoms questionnaire. At minimal working memory load, activation was seen in patients with greater severity of PCS in the working memory network. With an increase of working memory load, increase of activation was more pronounced in patients with greater severity of PCS. At high and increased working memory load, activation associated with the severity of PCS was seen in the posterior parietal area, parahippocampal gyrus, and posterior cingulate gyrus. Activation related to selective attention processing was increased with greater severity of PCS. The increased activity in relation to working memory and attention, and the recruitment of brain areas outside the working memory network at high working memory load, may be considered a reflection of the brain's compensatory response to microstructural injury in patients with PCS. Hum Brain Mapp, 2009. © 2008 Wiley‐Liss, Inc.     

Altered verbal working memory process in patients with Alzheimer's disease: an fMRI investigation

Impaired working memory processing is one of the broad range of cognitive deficits in patients with Alzheimer's disease (AD). We aimed to elucidate the differences in brain activities involved in the process of working memory between AD patients and healthy comparison subjects. Twelve patients with AD were recruited along with 12 healthy volunteers as a comparison group. Functional magnetic resonance imaging was employed to assess cortical activities during the performance of a 1-back working memory paradigm using the Korean alphabet as mnemonic content. Subsequently, the difference in neural activities between the 2 groups was analyzed. The AD group performed the tasks with reduced accuracy. Group comparison analysis revealed that the AD group showed decreased brain activity in the left frontal pole (Brodmann area, BA, 10), the left ventrolateral prefrontal cortex (BA47), the left insula (BA13) and the right premotor cortex (BA6) compared to the control group. The AD group showed increased activation in the left precuneus (BA7) compared to the control group. A decreased level of activation in the prefrontal cortex and an increased level of activation in the parietal neural networks from the patient group may document an altered verbal working memory process in the patients with AD.     

Brain activation during working memory 1 month after mild traumatic brain injury: a functional MRI study.

OBJECTIVE: To assess patterns of regional brain activation in response to varying working memory loads shortly after mild traumatic brain injury (MTBI). BACKGROUND: Many individuals complain of memory difficulty shortly after MTBI. Memory performance in these individuals can be normal despite these complaints. METHODS: Brain activation patterns in response to a working memory task (auditory n-back) were assessed with functional MRI in 12 MTBI patients within 1 month of their injury and in 11 healthy control subjects. RESULTS: Brain activation patterns differed between MTBI patients and control subjects in response to increasing working memory processing loads. Maximum intensity projections of statistical parametric maps in control subjects showed bifrontal and biparietal activation in response to a low processing load, with little additional increase in activation associated with the high load task. MTBI patients showed some activation during the low processing load task but significantly increased activation during the high load condition, particularly in the right parietal and right dorsolateral frontal regions. Task performance did not differ significantly between groups. CONCLUSION: MTBI patients differed from control subjects in activation pattern of working memory circuitry in response to different processing loads, despite similar task performance. This suggests that injury-related changes in ability to activate or to modulate working memory processing resources may underlie some of the memory complaints after MTBI.     

Working memory after traumatic brain injury in children

To investigate the effects of traumatic brain injury on working memory in children, we administered semantic (letter identity) and phonological (letter rhyme) N-back tasks to children who were on average 5 years post-mild (n = 54) or -severe (n = 26) traumatic brain injury and 44 typically developing children who were comparable in age. The correct detection of targets and false alarms were measured for each task. Memory load (which varied from 0 to 3 letters back) and age significantly affected the detection of targets and false alarms in both tasks. The severity of traumatic brain injury affected the correct detection of letters on the identity task and false alarms on the rhyme task. Traumatic brain injury severity also interacted with memory load in its effect on false alarms on the rhyme task. Traumatic brain injury results in impaired working memory and diminished inhibition in children. The N-back working memory task is feasible for administration to brain-injured children and potentially could be useful for studying brain activation associated with working memory and effects of drug therapy in this group of patients.     

Functional magnetic resonance imaging of working memory impairment after traumatic brain injury

OBJECTIVES: To examine patterns of brain activation while performing a working memory task in persons with moderate to severe traumatic brain injury (TBI) and healthy controls. It is well established that working memory is an area of cognition that is especially vulnerable to disruption after TBI. Although much has been learned about the system of cerebral representation of working memory in healthy people, little is known about how this system is disrupted by TBI. METHODS: Functional magnetic resonance imaging (fMRI) was used to assess brain activation during a working memory task (a modified version of the paced auditory serial addition test) in nine patients with TBI and seven healthy controls. RESULTS: Patients with TBI were able to perform the task, but made significantly more errors than healthy controls. Cerebral activation in both groups was found in similar regions of the frontal, parietal, and temporal lobes, and resembled patterns of activation found in previous neuroimaging studies of working memory in healthy persons. However, compared with the healthy controls, the TBI group displayed a pattern of cerebral activation that was more regionally dispersed and more lateralised to the right hemisphere. Differences in lateralisation were particularly evident in the frontal lobes. CONCLUSIONS: Impairment of working memory in TBI seems to be associated with alterations in functional cerebral activity.     

A neuropsychological comparison of psychotic disorder following traumatic brain injury, traumatic brain injury without psychotic disorder, and schizophrenia

Neuropsychological functioning in individuals with psychotic disorder following traumatic brain injury (PDFTBI), traumatic brain injury without psychosis (TBIWP), and schizophrenia were compared against each other and to the means of normal subjects. It was predicted that the PDFTBI group would be similar to the schizophrenic group in patterns of deficits, but milder in severity. Compared to scores from a normal sample, the PDFTBI group scored significantly lower in intelligence, vocabulary, verbal memory, and executive functioning, while the schizophrenic group scored significantly lower in intelligence, working memory, verbal memory, visual spatial abilities, and executive functioning. No differences were found between normal subjects and the TBIWP group. Implications of our findings for the conceptualization of psychotic disorders are discussed.     

A cross-sectional and follow-up functional MRI study with a working memory task in adolescent anorexia nervosa

Structural and functional brain abnormalities have been described in anorexia nervosa (AN). The objective of this study was to examine whether there is abnormal regional brain activation during a working memory task not associated with any emotional stimuli in adolescent patients with anorexia and to detect possible changes after weight recovery. Fourteen children and adolescents (age range 11–18 years) consecutively admitted with DSM-IV diagnosis of AN and fourteen control subjects of similar age were assessed by means of psychopathological scales and functional magnetic resonance imaging (fMRI) during a working memory task. After seven months of treatment and weight recovery, nine AN patients were reassessed. Before treatment, the AN group showed significantly higher activation than controls in temporal and parietal areas and especially in the temporal superior gyrus during performance of the cognitive task. Control subjects did not show greater activation than AN patients in any region. A negative correlation was found between brain activation and body mass index and a positive correlation between activation and depressive symptomatology. At follow-up after weight recovery, AN patients showed a decrease in brain activation in these areas and did not present differences with respect to controls. These results show that adolescent AN patients showed hyperactivation in the parietal and especially the temporal lobe during a working memory task, suggesting that they must make an additional effort to perform at normal levels. This activation correlated with clinical variables. In these young patients, differences with respect to controls disappeared after weight recovery.     

脑外伤后的注意、记忆和信息处理能力障碍及其恢复

用划消测验、同步听觉系列加法测验及临床记忆量表对105例脑外伤患者进行了测查,以观察脑外伤后患者的注意、记忆和信息处理能力受损程度,并在伤后5个月左右进行复查,以观察上述障碍的恢复情况。49名年龄和文化水平相当的正常人作为对照组。结果表明脑外伤后注意、记忆、信息处理能力均显著受损。5个月左右后中型脑外伤患者上述障碍已基本恢复。重型脑外伤患者上述心理功能虽有明显恢复,但尚未恢复到正常水平。     

脑损伤对记忆的影响

目的:探讨不同程度的脑损伤对意识、无意识记忆的影响。方法:采用Jacoby的加工分离程序(PDP),以具体图形和抽象图形为实验材料,分别对器质性、功能性脑损伤患者和正常健康者的意识、无意识提取贡献率进行测试。结果:在2种图形编码条件下,器质性脑损伤组和功能性脑损伤组的意识性提取贡献率均显著低于正常组。器质性脑损伤组的无意识提取贡献率显著低于正常组;而功能性脑损伤组的无意识提取贡献率与正常组差异无显著性。结论:不同程度脑损伤对意识、无意识记忆的影响不同。意识性记忆在脑损伤中比无意识记忆更容易受到伤害。     

Abnormal brain activation on functional MRI in cognitively asymptomatic HIV patients

BACKGROUND/OBJECTIVES: A previous fMRI study demonstrated increased brain activation during working memory tasks in patients with HIV with mild dementia. The current study aims to determine whether patients who are HIV-1 positive and have normal cognitive function also show increased brain activation on fMRI. METHODS: Blood oxygenation level-dependent (BOLD) fMRI was performed in 10 patients with HIV (CD <500) and 10 age-, sex-, education-, and handedness-matched seronegative subjects. Each subject performed a battery of neuropsychological tests and fMRI with three tasks (0-back, 1-back, and 2-back) that required different levels of attention for working memory. RESULTS: Compared with control subjects, patients with HIV showed greater magnitude of brain activation (BOLD signal intensity changes, p 相似文献