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。     

首发精神分裂症患者倒背数字作业的fMEI研究

目的利用功能磁共振成像(fMRI)探讨首发精神分裂症患者倒背数字作业激发图像的特点.方法 36例符合ICD-10诊断标准的(首发)精神分裂症患者及18名健康志愿者进行以倒背数字作业(backward digit span task, BDST)作为刺激模式、采用组块(block)设计的fMRI检查,经工作站处理后获功能图像.用阳性和阴性症状量表(PANSS)评价精神分裂症患者精神症状的严重程度. 结果 (1)健康志愿者与精神分裂症患者激活脑区的范围均较广泛,健康志愿者的左侧额上回、双侧额中回、左侧额下回、左侧中央前回、左侧顶上小叶、左侧缘上回、左侧颞下回及左侧枕颞外侧回等脑区均有明显激活.两组激活的脑区在额叶、颞叶、顶叶、枕叶及扣带回的分布,以及各脑区内部分布的差异均没有显著性(P>0.05).(2)健康志愿者与精神分裂症患者激活计数左侧额上回分别为16和11,左侧额下回分别为15和12,左侧中央前回分别为16和17,左侧颞下回分别为14和12,左侧顶上小叶分别为14和14,左侧缘上回分别为14和7,左侧枕颞外侧回分别为14和7,右侧中央前回分别为13和7,右侧枕颞外侧回分别为11和8,两组上述部位激活计数的差异均有显著性(P均＜0.05).(3)健康志愿者与精神分裂症患者左侧额叶背外侧的激活平均体积分别为(362±296)个体素和(79±101)个体素,差异有非常显著性(P=0.001);右侧顶叶后下部的激活平均体积分别为(448±273)个体素和(193±236)个体素,差异有显著性(P=0.039). 结论早期精神分裂症患者可能存在工作记忆缺陷,包括激活信息的保持及执行控制过程,激活信息的保持缺陷可能与左侧额叶腹外侧及顶叶后下部的功能低下有关,而执行控制缺陷可能与左侧额叶背外侧的功能低下有关.     

精神分裂症首次发病患者词语流畅性作业的功能磁共振成像研究

目的应用功能磁共振成像探讨精神分裂症首次发病(以下简称首发)患者词语流畅性作业激发图像的特点。方法以词语流畅性作业作为刺激模式,采用组块设计的功能磁共振成像技术,采集36例符合国际疾病分类第10版诊断标准的精神分裂症首发患者(精神分裂症组)及18名健康志愿者(正常对照组)的功能图像,并进行比较。精神分裂症组中有6例因不合作而被剔除。结果(1)两组激活脑区的范围均较广泛;(2)激活脑区数(个):精神分裂症组双侧额中回(均为16/30)、右额下回(14/30)、右中央前回(11/30)和右扣带回(15/30)等脑区的激活率均小于正常对照组(分别为16/18、16/18、15/18、13/18、15/18),差异有统计学意义(P<0.05);(3)激活脑区体积(体素):精神分裂症组左侧额叶背外侧(118±272)、左侧额叶腹外侧(176±293)、左侧扣带回前上部(142±169)均小于正常对照组(分别为545±809、514±427、279±192),差异有统计学意义(P<0.05)。结论早期精神分裂症患者可能存在长时记忆提取缺陷;搜寻特异目标的缺陷可能与双侧额下回的功能低下有关,对提取内容的核查及管理缺陷可能与双侧额中回的功能低下有关。     

首发精神分裂症患者治疗前后脑功能磁共振成像的研究

目的 利用功能磁共振成像(fMRI)探讨首发精神分裂症患者利培酮治疗前后认知功能激发图像的特点。方法 18例首发精神分裂症患者治疗前进行倒背数字作业的fMRI检查,经利培酮[(3.8±0.9)mg/d]治疗(57±9)d后复查fMRI(16例)。用阳性和阴性症状量表(PANSS)及治疗中需处理的不良反应症状量表评价精神症状的严重程度及不良反应。结果 (1)利培酮治疗后的PANSS减分率为(50±22)％,有效率为72％。(2)治疗前倒背数字作业激活范围较广泛,包括额叶、顶叶及颞叶等脑区。(3)左侧额上回治疗前激活脑区计数为4,治疗后计数为12,治疗前后激活脑区计数的差异有非常显著性(P=0.009);左侧额叶腹外侧面治疗前激活平均体积为(15±38)个体素,治疗后激活平均体积为(67±76)个体素,治疗前后的差异有显著性(P=0.046)。结论 首发精神分裂症患者在发病初期就存在工作记忆缺陷,这种缺陷可能与左侧额上回及额下回激活低下有关,利培酮治疗可改善患者的工作记忆缺陷。     

首发精神分裂症患者的功能磁共振初步研究

目的 利用血氧水平依赖性(blood oxygenation level-dependent,BOLD)功能磁共振成像(functional magnetic resonance imaging,fMRI)技术探讨首发精神分裂症患者治疗前后认知功能激发图像的特点。方法 13例首发精神分裂症患者入组,用利培酮或氯丙嗪治疗后9例患者复查fMRI。以词语流畅性作业(verbal fluency task,VF)作为任务,采用Block设计,用梯度回波-平面回波成像(GRE-EPI)序列采集数据,经工作站处理后获功能图像。结果 (1)VF激活受试者的额叶(前额叶)、顶叶及颞叶皮层;(2)复查的9例受试者中,7例激活增强,2例激活减弱;(3)治疗后激活增强的7例受试者的双侧额上、中、下回激活有增加趋势,而双侧颞上、中、下回激活有减少趋势(P>0.05);但左额叶背外侧面治疗后的激活明显强于治疗前(P=0.032)。结论 BOLD-fMRI可用于研究人脑的高级认知功能。首发精神分裂症患者治疗前后脑功能图像有明显变化,提示认知缺陷症状是可以治疗的。     

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.     

单相抑郁和双相抑郁患者在言语流畅任务下前额叶激活情况分析

目的探索单相抑郁(unipolar depression)和双相抑郁(bipolar depression)患者前额叶激活特点。方法通过近红外光脑成像(near infrared spectroscopy, NIRS)技术采集并比较69例单相抑郁患者(单相抑郁组)和68例双相抑郁患者(双相抑郁组)在言语流畅任务下前额叶的含氧血红蛋白浓度变化, 采用偏相关分析法分析24项汉密尔顿抑郁量表(Hamilton Depression Scale, HAMD)总分及各因子分与受试者前额叶激活的相关性。结果单相抑郁组和双相抑郁组患者在左侧前额叶背外侧区、双侧前额叶腹外侧区和眶额皮质区检测通道的含氧血红蛋白浓度变化差异有统计学意义(P<0.05), 且右侧前额叶背外侧区含氧血红蛋白浓度变化与双相抑郁和单相抑郁组抑郁症状的严重程度相关(P<0.05), 而左侧前额叶背外侧区含氧血红蛋白浓度变化与单相抑郁组抑郁症状的严重程度相关(P<0.05)。结论双相抑郁患者和单相抑郁患者在前额叶外侧区和眶额皮质的激活差异有统计学意义, 且双相抑郁患者左侧前额叶背外侧和右侧前额叶背外侧的激活与抑郁症...     

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.     

戒断期海洛因依赖者额叶认知功能的功能磁共振成像研究

目的 研究戒断期海洛因依赖者(AHD)的脑认知功能.方法 采用3.0 T磁共振成像系统,对30例AHD(AHD组)和18名健康对照者(对照组)在完成Go/NoGo任务时行全脑功能磁共振成像(fMRI)扫描,记录反应时间(RT).结果 (1)RT:AHD组在完成Go/NoGo任务时的RT[(394±34)ms]长于对照组[(374±26)ms;P<0.05].(2)fMRI:对照组在完成Go/NoGo任务时,诱发激活双侧前额叶内侧回、前扣带回以及双侧额下回等脑区;AHD组全脑活动普遍低,仅有双侧额上回和左侧额中回激活.两组间比较,AHD组激活显著低于对照组的区域主要位于在双侧额内侧回、前扣带回、额下回及双侧颞叶等脑区(P<0.005).结论 戒断期海洛因依赖者反应抑制功能障碍仍然存在,促进其认知功能的恢复可能成为戒毒、抗复吸的有效策略.     

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.     

The effect of musicianship on pitch memory in performance matched groups

We compared brain activation patterns between musicians and non-musicians (matched in performance score) while they performed a pitch memory task (using a sparse temporal sampling fMRI method). Both groups showed bilateral activation of the superior temporal, supramarginal, posterior middle and inferior frontal gyrus, and superior parietal lobe. Musicians showed more right temporal and supramarginal gyrus activation while non-musicians had more right primary and left secondary auditory cortex activation. Since both groups' performance were matched, these results probably indicate processing differences between groups that are possibly related to musical training. Non-musicians rely more on brain regions important for pitch discrimination while musicians prefer to use brain regions specialized in short-term memory and recall to perform well in this pitch memory task.     

Abnormal brain activity patterns during spatial working memory task in patients with end-stage renal disease on maintenance hemodialysis: a fMRI study

Hemodialysis (HD) is associated with cognitive impairment in patients with end-stage renal disease (ESRD). However, the neural mechanism of spatial working memory (SWM) impairment in HD-ESRD patients remains unclear. We investigated the abnormal alterations in SWM-associated brain activity patterns in HD-ESRD patients using blood oxygen level-dependent functional magnetic resonance imaging (BOLD-fMRI) technique during n-back tasks. Twenty-two HD-ESRD patients and 22 well-matched controls underwent an fMRI scan while undergoing a three-load n-back tasks with different difficulty levels. Cognitive and mental states were assessed using a battery of neuropsychologic tests. The HD-ESRD patients exhibited worse memory abilities than controls. Compared with the control group, the HD-ESRD patient group showed lower accuracy and longer response time under the n-back tasks, especially in the 2-back task. The patterns of brain activation changed under different working memory loads in the HD-ESRD patients, showing decreased activity in the right medial frontal gyrus and inferior frontal gyrus under 0-back and 1-back task, while more decreased activation in the bilateral frontal cortex, parietal lobule, anterior/posterior cingulate cortex and insula cortex under 2-back task. With the increase of task difficulty, the activation degree of the frontal and parietal cortex decreased. More importantly, we found that lower activation in frontal cortex and parietal lobule was associated with worse cognitive function in the HD-ESRD patients. These results demonstrate that the abnormal brain activity patterns of frontal cortex and parietal lobule may reflect the neural mediation of SWM impairment.

     

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...     

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.     

Functional neuroanatomy of visuospatial working memory in fragile X syndrome: relation to behavioral and molecular measures.

OBJECTIVE: Fragile X syndrome is a neurogenetic disorder that is the most common known heritable cause of neurodevelopmental disability. This study examined the neural substrates of working memory in female subjects with fragile X syndrome. Possible correlations among behavioral measures, brain activation, and the FMR1 gene product (FMRP expression), as well as between IQ and behavioral measures, were investigated. METHOD: Functional magnetic resonance imaging was used to examine visuospatial working memory in 10 female subjects with fragile X syndrome and 15 typically developing female subjects (ages 10-23 years). Subjects performed standard 1-back and 2-back visuospatial working memory tasks. Brain activation was examined in four regions of the cortex known to play a critical role in visuospatial working memory. Correlations between behavioral, neuroimaging, and molecular measures were examined. RESULTS: Relative to the comparison group, subjects with fragile X syndrome performed significantly worse on the 2-back task but not on the 1-back task. In a region-of-interest analysis focused on the inferior frontal gyrus, middle frontal gyrus, superior parietal lobule, and supramarginal gyrus, comparison subjects showed significantly increased brain activation between the 1-back and 2-back tasks, but subjects with fragile X syndrome showed no change in activation between the two tasks. Significant correlations were found in comparison subjects between activation in the frontal and parietal regions and the rate of correct responses on the 2-back task, but not on the 1-back task. In subjects with fragile X syndrome, significant correlations were found during the 2-back task between FMRP expression and activation in the right inferior and bilateral middle frontal gyri and the bilateral supramarginal gyri. CONCLUSIONS: Subjects with fragile X syndrome are unable to modulate activation in the prefrontal and parietal cortex in response to an increasing working memory load, and these deficits are related to a lower level of FMRP expression in fragile X syndrome subjects than in normal comparison subjects. The observed correlations between biological markers and brain activation provide new evidence for links between gene expression and cognition.     

Neural correlates of episodic and semantic memory retrieval in borderline personality disorder: An fMRI study

Verbal memory impairment in borderline personality disorder (BPD) is still a matter of debate. In this study we combine investigations of both, memory retrieval as well as underlying neural circuits in BPD. Functional magnetic resonance imaging (fMRI) was used to study regional brain activation in 18 right-handed female patients with BPD and 18 matched controls during the retrieval of an episodic memory retrieval (EMR) task (free recall of a word list) and a semantic memory retrieval (SMR) task (verbal fluency). Despite unaffected performance in EMR and SMR, patients with BPD showed task-specific increased activation compared with controls. During EMR, the increased activation encompassed the posterior cingulate cortex bilaterally, the left middle and superior temporal gyrus, the right inferior frontal gyrus, and the right angular gyrus. SMR was associated with increased activation of the posterior cingulate cortex, of the right fusiform gyrus, of the left anterior cingulate cortex, and of the left postcentral gyrus. Our findings suggest that BPD patients may need to engage larger brain areas to reach a level of performance in episodic and semantic retrieval tasks that is comparable to that of healthy controls.     

Default network connectivity during a working memory task

The default network exhibits correlated activity at rest and has shown decreased activation during performance of cognitive tasks. There has been little investigation of changes in connectivity of this network during task performance. In this study, we examined task‐related modulation of connectivity between two seed regions from the default network posterior cingulated cortex (PCC) and medial prefrontal cortex (mPFC) and the rest of the brain in 12 healthy adults. The purpose was to determine (1) whether connectivity within the default network differs between a resting state and performance of a cognitive (working memory) task and (2) whether connectivity differs between these nodes of the default network and other brain regions, particularly those implicated in cognitive tasks. There was little change in connectivity with the other main areas of the default network for either seed region, but moderate task‐related changes in connectivity occurred between seed regions and regions outside the default network. For example, connectivity of the mPFC with the right insula and the right superior frontal gyrus decreased during task performance. Increased connectivity during the working memory task occurred between the PCC and bilateral inferior frontal gyri, and between the mPFC and the left inferior frontal gyrus, cuneus, superior parietal lobule, middle temporal gyrus and cerebellum. Overall, the areas showing greater correlation with the default network seed regions during task than at rest have been previously implicated in working memory tasks. These changes may reflect a decrease in the negative correlations occurring between the default and task‐positive networks at rest. Hum Brain Mapp, 2011. © 2010 Wiley‐Liss, Inc.     

Compensatory recruitment after sleep deprivation and the relationship with performance

This study examined the effects of total sleep deprivation (TSD) on cerebral responses to a verbal learning task with two levels of word difficulty. A total of 32 subjects were studied with functional magnetic resonance imaging (FMRI) after normal sleep and following 36 h of TSD. Cerebral responses to EASY words were identical on both nights, but several brain regions showed increased activation to HARD words following TSD compared with following a normal night of sleep (NORM). These regions included bilateral inferior frontal gyrus, bilateral dorsolateral prefrontal cortex, and bilateral inferior parietal lobe. Better free recall performance on the HARD words after TSD was related to increased cerebral responses within the left inferior and superior parietal lobes and left inferior frontal gyrus. Recall was negatively related to activation within the right inferior frontal gyrus. Overall, the findings support the predictions of the compensatory recruitment hypothesis that task demands influence both the likelihood and location of increased cerebral activation during task performance following TSD, and refine that hypothesis by identifying a specific task demand that plays a role. The performance relationships suggest increased activation may be both beneficial (compensatory) and interfere with task performance, depending on the brain regions involved.     

A Longitudinal Functional Magnetic Resonance Imaging Study of Working Memory in Patients Following a Transient Ischemic Attack: A Preliminary Study

In this study, we used functional magnetic resonance imaging (fMRI) to investigate longitudinal changes in brain activation during a verbal working memory (VWM) task performed by patients who had experienced a transient ischemic attack (TIA). Twenty-five first-ever TIA patients without visible lesions in conventional MRI and 25 healthy volunteers were enrolled. VWM task-related fMRI was conducted 1 week and 3 months post-TIA. The brain activity evoked by the task and changes over time were assessed. We found that, compared with controls, patients exhibited an increased activation in the bilateral inferior frontal gyrus (IFG), right dorsolateral prefrontal cortex (DLPFC), insula, inferior parietal lobe (IPL), and cerebellum during the task performed 1 week post-TIA. But only the right IFG still exhibited an increased activation at 3 months post-TIA. A direct comparison of fMRI data between 1 week and 3 months post-TIA showed greater activation in the bilateral middle temporal gyrus, right DLPFC, IPL, cerebellum, and left IFG in patients at 1 week post-TIA. We conclude that brain activity patterns induced by a VWM task remain dynamic for a period of time after a TIA, despite the cessation of clinical symptoms. Normalization of the VWM activation pattern may be progressively achieved after transient episodes of ischemia in TIA patients.