运动想象联合常规康复训练促进脑卒中患者功能恢复的静息态功能性磁共振研究

目的 利用静息态功能性磁共振成像（fMRI）研究脑卒中患者运动想象训练（MIT）联合常规康复训练后上肢功能恢复潜在的脑重塑机制。 方法 选择10例脑卒中偏瘫患者，进行MIT，每周5次，每次约30 min，共4周，同时进行常规康复训练，每周5次，每次约40 min，共4周。另选取10例年龄和性别与MIT组相匹配的健康受试者作为健康对照组。干预前和干预4周后，应用Fugl-Meyer运动功能量表上肢部分（FMA-UE）和改良Barthel指数（MBI）评估受试者的上肢运动功能和日常活动能力。干预前、后分别对患者进行fMRI检查，统计患侧初级运动区（M1）与全脑各脑区间的功能连接，计算M1和初级感觉区（S1）的偏侧化指数（LI）。 结果 干预后，MIT组FMA-UE评分从［（23.3±14.9）分］升高到［（33.6±13.6）分］，MBI从［（58.0±15.5）分］升高到［（72.5±16.2）分］，差异均有统计学意义（P<0.01）。MIT组患者患侧M1与健侧MI、健侧S1、健侧额叶的功能连接增强，患侧M1与患侧旁中央小叶、患侧前扣带回的功能连接也增强。MIT组干预前脑卒中患者的LI在M1、S1两区均较健康对照组明显增加（干预前LIM1为0.43，LIS1为0.37，健康对照组接近于0），干预后LIM1和LIS1均有所降低，并趋向于健康人数值（干预后LIM1为0.22，干预后LIS1为0.34），LIM1显著下降（P<0.05），LIS1未显著下降（P>0.05）。 结论 MIT联合常规康复训练可改善脑卒中患者的上肢运动功能和日常活动能力，经过4周干预后患者患侧M1和健侧M1的功能连接被显著修复，和双侧多个非初级运动脑区的功能连接也增加，逐步恢复了双侧初级运动区功能连接的对称性，这些可能是运动想象联合常规康复训练改善脑卒中患者运动功能的脑重塑机制。     

Disrupted thalamocortical connectivity in PSP: a resting-state fMRI, DTI, and VBM study

Progressive supranuclear palsy (PSP) is associated with pathological changes along the dentatorubrothalamic tract and in premotor cortex. We aimed to assess whether functional neural connectivity is disrupted along this pathway in PSP, and to determine how functional changes relate to changes in structure and diffusion. Eighteen probable PSP subjects and 18 controls had resting-state (task-free) fMRI, diffusion tensor imaging and structural MRI. Functional connectivity was assessed between thalamus and the rest of the brain, and within the basal ganglia, salience and default mode networks (DMN). Patterns of atrophy were assessed using voxel-based morphometry, and patterns of white matter tract degeneration were assessed using tract-based spatial statistics. Reduced in-phase functional connectivity was observed between the thalamus and premotor cortex including supplemental motor area (SMA), striatum, thalamus and cerebellum in PSP. Reduced connectivity in premotor cortex, striatum and thalamus were observed in the basal ganglia network and DMN, with subcortical salience network reductions. Tract degeneration was observed between cerebellum and thalamus and in superior longitudinal fasciculus, with grey matter loss in frontal lobe, premotor cortex, SMA and caudate nucleus. SMA functional connectivity correlated with SMA volume and measures of cognitive and motor dysfunction, while thalamic connectivity correlated with degeneration of superior cerebellar peduncles. PSP is therefore associated with disrupted thalamocortical connectivity that is associated with degeneration of the dentatorubrothalamic tract and the presence of cortical atrophy.     

Abnormal baseline brain activity in patients with neuromyelitis optica: A resting-state fMRI study

Purpose

Recent immunopathologic and MRI findings suggest that tissue damage in neuromyelitis optica (NMO) is not limited to spinal cord and optic nerve, but also in brain. Baseline brain activity can reveal the brain functional changes to the tissue damages and give clues to the pathophysiology of NMO, however, it has never been explored by resting-state functional MRI (fMRI). We used regional amplitude of low frequency fluctuation (ALFF) as an index in resting-state fMRI to investigate how baseline brain activity changes in patients with NMO.

Methods

Resting-state fMRIs collected from seventeen NMO patients and seventeen age- and sex-matched normal controls were compared to investigate the ALFF difference between the two groups. The relationships between ALFF in regions with significant group differences and the EDSS (Expanded Disability Status Scale), disease duration were further explored.

Results

Our results showed that NMO patients had significantly decreased ALFF in precuneus, posterior cingulate cortex (PCC) and lingual gyrus; and increased ALFF in middle frontal gyrus, caudate nucleus and thalamus, compared to normal controls. Moderate negative correlations were found between the EDSS and ALFF in the left middle frontal gyrus (r = −0.436, p = 0.040) and the left caudate (r = −0.542, p = 0.012).

Conclusion

The abnormal baseline brain activity shown by resting-state fMRI in NMO is relevant to cognition, visual and motor systems. It implicates a complex baseline brain status of both functional impairments and adaptations caused by tissue damages in these systems, which gives clues to the pathophysiology of NMO.     

The 'resting-state hypothesis' of major depressive disorder-a translational subcortical-cortical framework for a system disorder

Major depressive disorder (MDD) has traditionally been characterized by various psychological symptoms, involvement of diverse functional systems (e.g., somatic, affect, cognition, reward, etc.), and with progress in neuroscience, an increasing number of brain regions. This has led to the general assumption that MDD is a stress–responsive brain ‘system disorder’ where either one or several alterations infiltrate a large number of functional systems in the brain that control the organism's somatic, affective, and cognitive life. However, while the effects or consequences of the abnormal changes in the functional systems of, for instance affect, cognition or reward have been investigated extensively, the underlying core mechanism(s) underlying MDD remain unknown. Hypotheses are proliferating rapidly, though. Based on recent findings, we will entertain an abnormality in the resting-state activity in MDD to be a core feature. Based on both animal and human data, we hypothesize that abnormal resting-state activity levels may impact stimulus-induced neural activity in medially situated core systems for self-representation as well as external stimulus (especially stress, specifically separation distress) interactions. Moreover, due to nested hierarchy between subcortical and cortical regions, we assume ‘highjacking’ of higher cortical affective and cognitive functions by lower subcortical primary-process emotional systems. This may account for the predominance of negative affect in somatic and cognitive functional system operations with the consecutive generation of the diverse symptoms in MDD. We will here focus on the neuroanatomical and biochemical basis of resting-state abnormalities in MDD including their linkage to the diverse psychopathological symptoms in depression. However, our ‘resting-state hypothesis’ may go well beyond that by being sufficiently precise to be linked to genetic, social, immunological, and endocrine dimensions and hypotheses as well as to clinical dimensions like endophenotypes and various diagnostic-prognostic biomarkers. Taken together, our ‘resting-state hypothesis’ may be considered a first tentative framework for MDD that integrates translational data, the various dimensions, and subcortical–cortical systems while at the same time providing the link to the clinical level of symptoms, endophenotypes and biomarkers.     

2型糖尿病患者大脑灰质结构和神经活动协同性的磁共振成像研究

目的 利用磁共振成像技术结合基于体素的形态学(voxel-based morphology,VBM)及静息态局部一致性(regional homogeneity,ReHo)的分析方法探索2型糖尿病(type 2 diabetes mellitus,T2DM)患者大脑神经结构的微观变化及神经活动协同性的改变.方法 研究共纳入26例T2DM患者及24名健康自愿者对照,采集所有被试大脑结构像及静息态功能数据.计算全脑体素的灰质体积(gray matter volume,GMV)及ReHo值并进行组间统计分析,提取存在显著差异脑区的GMV/ReHo值与临床数据做相关分析.结果 VBM结果显示与正常对照组相比T2DM患者双侧纹状体、双侧丘脑、左侧岛叶及左侧小脑的部分区域灰质体积明显降低(P ＜0.05,FDR校正).ReHo减低的脑区(P＜0.05,FDR校正)主要位于双侧舌回/距状裂周围皮层、楔叶、左侧枕上回/枕中回.ReHo升高的脑区主要位于颞叶、双侧纹状体、两侧丘脑、右侧额中回.患者双侧丘脑、右侧纹状体灰质体积与糖化血红蛋白值呈负相关.结论 T2DM患者纹状体、丘脑等灰质核团存在广泛的结构萎缩,并且这种结构的缺损与长期的血糖控制密切相关.局部脑区神经功能紊乱可能是患者认知功能损伤的基础,纹状体、丘脑等灰质核团体积萎缩而功能活动一致性增强可能是糖尿病脑病中枢系统损伤的早期代偿性表现.     

多系统萎缩患者静息态下脑活动的局部一致性

目的：采用静息态功能磁共振（resting state functional magnetic resonance image, rs-fMRI）方法探讨不同亚型多系统萎缩（multiple system atrophy, MSA）患者脑局部一致性（regional homogeneity, ReHo）的变化及其与临床症状严重程度的相关性。方法：对48例MSA患者（MSA-C型28例及MSA-P型20例）和27例健康对照进行rs-fMRI扫描,比较3组间ReHo的差异,采用简易精神状态量表（MMSE）、蒙特利尔认知评估量表（MoCA）、统一的MSA评分量表（UMSARS）等评估临床症状,并分析MSA患者ReHo值与临床症状严重程度之间的关系。结果：①相对于对照组,MSA-C组双侧楔前叶、左侧海马、左侧枕中回、小脑蚓部Ⅴ～Ⅵ ReHo增高,左侧小脑前/后叶ReHo减低;MSA-P组双侧丘脑、左侧尾状核、脑干、小脑蚓部Ⅴ ReHo增高,左侧小脑前/后叶ReHo减低;相对于MSA-P组,MSA-C组左侧楔前叶、左侧海马、左侧颞中回ReHo增高,右侧枕中回ReHo减低。②MSA-C组双侧楔前叶与MoCA评分呈负相关,MSA-P组双侧丘脑与UMSARS-Ⅱ评分呈正相关。结论：静息态下MSA患者存在局部脑区的神经元活动一致性异常,这些脑区异常可能与MSA的病理机制有关。     

静息态脑功能成像与皮层电刺激定位皮质运动区的对照研究

目的 以术中皮层电刺激为对照,评价运动区附近脑肿瘤患者术前运用基于血氧水平依赖(BOLD)的静息态功能磁共振成像(rs-fMRI)方法定位皮质运动区的准确性.方法 选取18例运动区脑肿瘤患者,手术前采用rs-fMRI定位皮质运动区,以术中皮层电刺激作为皮质运动区定位的标准技术,比较两种技术的符合度,以评价rs-fMRI定位皮质运动区的准确性.结果 rs-fMRI与术中皮层电刺激的吻合率为92.9％,肿瘤全切率为77.8％,11例术后肌力不变,4例术后肌力好转,3例术后肌力下降.结论 rs-fMRI具有较高的敏感性和精确度,可作为术前皮质运动区定位的新方法,为手术方案的制定及预后评估提供有价值的信息.     

A geometric view of global signal confounds in resting-state functional MRI

Resting-state functional magnetic resonance imaging (fMRI) is proving to be an effective tool for mapping the long-range functional connections of the brain in both health and disease. One of the primary measures of connectivity is the correlation between the blood oxygenation level dependent (BOLD) time series observed in different brain regions. The computation of the correlation is often dominated by the presence of a strong global component that can introduce significant variability across functional connectivity maps acquired from different experimental scans or subjects. To address this issue, a variety of global signal correction methods have been proposed, but there is currently a lack of a clear consensus on the best approach to use. Furthermore, there has been concern that some global signal correction methods, such as global signal regression, may produce significant negative bias in the correlation values. In this paper we introduce a framework for visualizing the signal structure of resting-state fMRI data and characterizing the properties of the global signal. Using this framework, we demonstrate that a portion of the global signal can be viewed as an additive confound that increases with the mean BOLD amplitude. An approach for minimizing the contribution of this additive confound is presented, and an initial comparison with existing global signal correction methods is provided.     

多发性硬化（MS）患者静息态视觉网络的脑功能研究

目的评价静息态功能磁共振（rfMRI）方法研究多发性硬化患者视觉网络的价值。方法 34例多发性硬化患者及性别、年龄相匹配的34名健康志愿者均接受静息态功能MRI扫描（采用西门子MAGNRTOM3.0T Trio Tim）,基于Mat-lab2009a平台使用独立成分分析法（independent component analysis,ICA）提取并比较两组视觉网络功能成分的差异,数据统计采用统计参数图（SPM8）软件（双样本t检验）。结果与对照组比较,患者组在左侧楔叶、双侧距状裂、双侧枕上回、左侧楔前叶出现神经元活动增强区。说明患者组静息态视觉网络存在一定的代偿。结论 rfMRI是研究脑功能网络的一种有效办法。     

Interaction between aging and neurodegeneration in amyotrophic lateral sclerosis

We assessed the spontaneous blood-oxygen-level-dependent signal fluctuations in the resting-state brain networks of amyotrophic lateral sclerosis patients and their relation to physiologically sensitive and disease modified functional magnetic resonance imaging parameters.