fMRI analysis of active, passive and electrically stimulated ankle dorsiflexion

Ankle dorsiflexion (ADF) is an integral component in gait. The objective of this study was to define, using functional magnetic resonance imaging (fMRI) in healthy volunteers (n=12), the brain regions that are activated during Electrical Stimulation (ES)-induced ADF movements, and compare this to the pattern of activation occurring during active and passive ADF. Concurrent electromyography (EMG) was used to monitor the tibialis anterior muscle activity so as to allow EMG-guided fMRI analysis to be performed. Patterns of cortical and sub-cortical activation in response to active, passive and ES-induced ADF movement were identified. EMG-guided fMRI analysis was shown to improve detection and reduce inter-session variance for active and ES tasks. A significantly greater number of voxels were activated during active and ES-induced ADF compared to passive ADF in contralateral primary motor (M1), primary sensory (SI), and secondary somatosensory (SII) areas, as well as in supplementary motor area (SMA) and cingulate motor areas (CMA); bilateral dorsal and ventral premotor areas and cerebellum VI. The contrast of active greater than ES-induced ADF showed increased activation in SMA, contralateral PMdr; bilateral PMvr, dorsolateral prefrontal cortex and CMA; and ipsilateral cerebellum IV. Active ADF generated greater activation in brain areas responsible for motor planning, execution and visuomotor co-ordination. ES-induced activation was greater in bilateral SII and insula than for active ADF, hypothesised to result from increased sensory integration, but also possibly due to a nociceptive component to ES.     

Significant differences in central imaging of histamine-induced itch between atopic dermatitis and healthy subjects

Background/aim: This is the first investigation of the central processing of itch in the brain in 8 subjects with atopic dermatitis (AD) in comparison to 6 healthy controls (HC), comparing histamine‐induced itch related activations in the frontal, prefrontal, parietal, cingulate cortex, thalamus, basal ganglia and cerebellum. Methods: We employed 1% histamine‐dihydrochlorid‐iontophoresis of the left hand, recorded H₂ ¹⁵O‐PET‐scans and perception of itch intensity on a numeric rating scale. Results: There was no significant difference in perceived itch intensity between AD and HC. Significant increase in rCBF was found in HC in the contralateral somatosensory and motor cortex, midcingulate gyrus, and ipsilateral prefrontal cortex; in AD: in the contralateral thalamus, somatosensory, motor and prefrontal cortex and cerebellum, in the ipsilateral precentral, prefrontal, orbitofrontal cortex, insula, pallidum and cerebellum. More brain sites were activated in AD than in HC. Activation in AD was significantly higher in the contralateral thalamus, ipsilateral caudate and pallidum. Conclusions: We interpret our findings as possible central correlates of changes in the motor system in subjects with chronic itch, with activation of the basal ganglia possibly correlating to the vicious itch‐scratch‐circle in subjects with chronic itching skin diseases. However, further neuroimaging studies in healthy subjects and also in different skin diseases are needed to understand the complex mechanisms of the processing of itch.     

Age-related networks of regional covariance in MRI gray matter: Reproducible multivariate patterns in healthy aging

Healthy aging is associated with brain volume reductions that involve the frontal cortex, but also affect other brain regions. We sought to identify an age-related network pattern of MRI gray matter using a multivariate statistical model of regional covariance, the Scaled Subprofile Model (SSM) with voxel based morphometry (VBM) in 29 healthy adults, 23-84 years of age (Group 1). In addition, we evaluated the reproducibility of the age-related gray matter pattern derived from a prior SSM VBM study of 26 healthy adults, 22-77 years of age (Group 2; Alexander et al., 2006) in relation to the current sample and tested the ability of the network analysis to extract an age-related pattern from both cohorts combined. The SSM VBM analysis of Group 1 identified a regional pattern of gray matter atrophy associated with healthy aging (R² = 0.64, p < 0.000001) that included extensive reductions in bilateral dorsolateral and medial frontal, anterior cingulate, insula/perisylvian, precuneus, parietotemporal, and caudate regions with areas of relative preservation in bilateral cerebellum, thalamus, putamen, mid cingulate, and temporal pole regions. The age-related SSM VBM gray matter pattern, previously reported for Group 2, was highly expressed in Group 1 (R² = 0.52, p < 0.00002). SSM analysis of the combined cohorts extracted a common age-related pattern of gray matter showing reductions involving bilateral medial frontal, insula/perisylvian, anterior cingulate and, to a lesser extent, bilateral dorsolateral prefrontal, lateral temporal, parietal, and caudate brain regions with relative preservation in bilateral cerebellum, temporal pole, and right thalamic regions. The results suggest that healthy aging is associated with a regionally distributed pattern of gray matter atrophy that has reproducible regional features. Whereas the network patterns of atrophy included parietal, temporal, and subcortical regions, involvement of the frontal brain regions showed the most consistently extensive and reliable reductions across samples. Network analysis with SSM VBM can help detect reproducible age-related MRI patterns, assisting efforts in the study of healthy and pathological aging.     

多系统萎缩患者轻度认知功能障碍的静息态低频振幅研究

目的采用静息态功能磁共振成像(resting state functional MRI,rs-fMRI)低频振幅(amplitude of low-frequency fluctuation,ALFF)方法探究多系统萎缩(multiple system atrophy,MSA)患者认知相关的自发脑活动改变。材料与方法对29例认知功能正常的MSA患者(MSA-normal cognition,MSA-NC)、33例伴轻度认知功能障碍的MSA患者(MSA-mild cognitive impairment,MSA-MCI)与33名健康对照者(healthy control,HC)进行rs-fMRI扫描。应用ALFF方法比较各组间自发脑活动改变,并对患者组间存在差异脑区的ALFF值与认知评分进行相关性分析。结果与HC相比,MSA-NC在左侧角回及右侧颞中回出现ALFF增强;与HC相比,MSA-MCI在双侧背外侧前额叶、内侧前额叶、前扣带回、中扣带回出现ALFF减低,而在双侧颞下回、角回、左侧枕中回、右侧颞中回、楔前叶及右侧小脑、小脑蚓出现ALFF增强。与MSA-NC相比,MSA-MCI在右侧额叶皮层出现ALFF减低,并与蒙特利尔认知评估量表(montreal cognitive assessment scale,MoCA)评分呈正相关(r=0.531,P<0.05);在右侧小脑出现ALFF增强,并与MoCA评分呈负相关(r=-0.499,P<0.05)。结论MSA特异的轻度认知功能障碍是由小脑与额叶皮层损伤共同介导,其中小脑起到代偿作用。     

正常人三种模式手指运动时脑激活区域的功能磁共振研究

目的　研究简单动作 (反复连续的手指对指动作 )、随意动作 (抓物体 )和假想动作三种运动模式时 ,脑功能区域的活动机制。方法　利用功能磁共振 (fMRI)影像技术分别摄取 1 0例正常人的利手和非利手在不同运动模式下的双侧脑激活区域 ,再进行机制分析。结果　随意动作时 ,脑同侧激活区的数目多于简单动作 (P <0 .0 5) ,而对侧无明显差异。在简单动作和随意动作中 ,无论利手或非利手 ,主要的激活区为对侧的初级感觉运动皮质 (SM1 ) ,但非利手也可激活同侧少量的SM1。另外 ,脑双侧辅助运动区 (SMA)、前运动区 (PMA) ,对侧顶上小叶 ,同侧小脑也有明显激活 ;偶见基底节激活。假想动作时主要激活额上回、额中回、顶上小叶 ,另见少量扣带回、小脑、脑干、中央旁小叶、基底节处激活。结论　利手的简单动作支配主要在对侧脑SM1 ,而双侧的SM1参与了非利手的简单动作。随意动作属于复杂动作 ,参与动作的区域多于简单动作 ,且双侧SMA均参与 ,可能与双手协调、记忆动作模式的选择、动作顺序的执行有关。假想动作时主要由SMA、PMA支配。该机制对脑卒中的运动训练具有指导意义     

正常人体针灸效应功能性磁共振成像的研究

目的评价针刺体表穴位对脑部相应区域的功能性磁共振成像(fMRI)表现。方法17例健康志愿者，在1，5TMRI仪上进行针刺足三里(S36)、阳陵泉(G34)的实时动态fMRI检查，观察并分析针刺效果明显者的脑部功能变化情况，判断针刺效果及其意义。结果17例志愿者中13例检查成功，可见躯体感觉运动区(SMC)、运动前区(PMC)、副运动区(SMA)激活明显，额叶前部、扣带回、尾状核头部、豆状核及丘脑、岛叶、岛盖皮质大多有大面积明显激活，小脑和桥脑也可见有激活，在左侧丘脑、SMA、SMC、PMC激活区附近有信号减低的现象，但激活的像素数不多；信号减低区包括两侧额叶内侧面皮质，双侧扣带回前部皮质，两侧海马区，右侧眶回、基底节、尾状核头部等。结论针刺对脑部相关穴位的治疗效应显著，可产生广泛而复杂的脑功能变化，fMRI可清楚显示针刺效应引起的脑部功能变化，是针刺机制及效应良好且直观的评价途径。     

Central activation by histamine-induced itch: analogies to pain processing: a correlational analysis of O-15 H2O positron emission tomography studies

The aim of this study was to identify the functional cerebral network involved in the central processing of itch and to detect analogies and differences to previously identified cerebral activation patterns triggered by painful noxious stimuli. Repeated positron emission tomography regional cerebral blood flow (rCBF) measurements using O15-labeled water were performed in six healthy right-handed male subjects (mean age 32 +/- 2 years). Each subject underwent 12 sequential rCBF measurements. In all subjects a standardized skin prick test was performed on the right forearm 2 min before each rCBF measurement. For activation, histamine was applied in nine tests in logarithmically increasing concentrations from 0.03 to 8%. Three tests were performed with isotonic saline solution serving as a control condition. Itch intensity and unpleasantness were registered with a visual analogue scale during each test. Subtraction analysis between activation and control conditions as well as correlation analysis with covariates were performed. Itch induced a significant activation in the predominantly contralateral somatosensory cortex and in the ipsilateral and contralateral motor areas (supplementary motor area (SMA), premotor cortex, primary motor cortex). Additional significant activations were found in the prefrontal cortex and the cingulate gyrus, but not in subcortical structures nor in the secondary somatosensory cortex. In correlation analyses, several cortical areas showed a graded increase in rCBF with the logarithm of the histamine concentration (bilateral sensorimotor areas and cingulate cortex; contralateral insula, superior temporal cortex and prefrontal cortex) and with itch unpleasantness (contralateral sensorimotor cortex, prefrontal cortex and posterior insula; ipsilateral SMA). Induction of itch results in the activation of a distributed cerebral network. Itch and pain seem to share common pathways (a medial and a lateral processing pathway and a strong projection to the motor system). In contrast to pain activation studies, no subcortical (i.e. thalamic) activations were detected and correlation analyses suggest differences in subjective processing of the two sensations.     

Alterations in pain processing circuitries in episodic migraine

BackgroundThe precise underlying mechanisms of migraine remain unknown. Although we have previously shown acute orofacial pain evoked changes within the brainstem of individuals with migraine, we do not know if these brainstem alterations are driven by changes in higher cortical regions. The aim of this investigation is to extend our previous investigation to determine if higher brain centers display altered activation patterns and connectivity in migraineurs during acute orofacial noxious stimuli.MethodsFunctional magnetic resonance imaging was performed in 29 healthy controls and 25 migraineurs during the interictal and immediately (within 24-h) prior to migraine phases. We assessed activation of higher cortical areas during noxious orofacial heat stimulation using a thermode device and assessed whole scan and pain-related changes in connectivity.ResultsDespite similar overall pain intensity ratings between all three groups, migraineurs in the group immediately prior to migraine displayed greater activation of the ipsilateral nucleus accumbens, the contralateral ventrolateral prefrontal cortex and two clusters in the dorsolateral prefrontal cortex (dlPFC). Reduced whole scan dlPFC [Z + 44] connectivity with cortical/subcortical and brainstem regions involved in pain modulation such as the putamen and primary motor cortex was demonstrated in migraineurs. Pain-related changes in connectivity of the dlPFC and the hypothalamus immediately prior to migraine was also found to be reduced with brainstem pain modulatory areas such as the rostral ventromedial medulla and dorsolateral pons.ConclusionsThese data reveal that the modulation of brainstem pain modulatory areas by higher cortical regions may be aberrant during pain and these alterations in this descending pain modulatory pathway manifests exclusively prior to the development of a migraine attack.     

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。     

2型糖尿病患者下丘脑功能连接的静息态功能磁共振研究

目的利用静息态功能磁共振技术探索2型糖尿病(T2DM)患者下丘脑与其他脑区功能连接的改变,明确T2DM是否损伤下丘脑的相关功能连接。材料与方法本研究共纳入59名T2DM患者及49名对照组志愿者,通过德国西门子MR仪采集T1WI、T2WI、T2压水序列、高分辨率3D T1WI结构像和静息态功能数据,计算下丘脑与全脑体素的功能连接值并进行组间比较,然后提取组间存在显著差异脑区的功能连接平均值并对其与临床数据进行相关性分析。结果 T2DM患者左、右侧下丘脑与右侧桥脑、左背外侧前额叶、眶额皮层、左顶下小叶、右侧枕中回间的功能连接强度均低于正常组(P0.05)。除此之外,左侧下丘脑与左侧梭状回、右侧颞下回、左侧楔前叶间的功能连接强度显著减低,左侧下丘脑与左侧岛叶间的功能连接强度显著增高(P0.05);右侧下丘脑与左侧舌回、右侧中央前回/右侧中央后回间的功能连接强度显著减低(P0.05)。相关性分析结果显示左侧下丘脑-左背外侧前额叶间功能连接强度的减低与糖化血红蛋白值存在负相关性(r=–0.24,P=0.04)。结论 T2DM损害了下丘脑与多个脑区的功能连接,其中同侧下丘脑与背外侧前额叶间功能连接减低与糖尿病严重程度相关。静息态功能磁共振能够反映2型糖尿病的严重程度。     

fMRI评价正常老年人腕关节被动运动下脑激活区

目的 用功能磁共振技术观察正常老年人双侧腕关节被动运动时脑区激活情况.方法 对30例正常的右利手老年受试者分别进行双侧腕关节被动运动的功能MR扫描,采用SPM2软件进行数据分析和脑功能区定位.结果 利手(右手)运动主要激活对侧感觉运动皮质、运动前区,双侧辅助运动区、后顶叶及同侧小脑;非利手运动时除激活上述脑区外,还激活了同侧运动感觉区和对侧小脑,且对侧运动前区、双侧辅助运动区和同侧小脑的激活体积明显大于利手腕关节运动.结论 被动运动依赖于大脑皮质和小脑等许多与运动相关的脑功能区的参与;与利手腕关节运动相比,非利手腕关节运动更依赖于对侧PMC、双侧SMA和同侧小脑等运动区.     

应用静息态功能磁共振成像分数低频振幅技术观察脑梗死患者大脑基线功能的变化

目的 应用静息态功能磁共振成像分数低频振幅(fALFF)技术,探讨脑梗死患者大脑基线功能的变化。方法 采用fALFF算法观察右侧皮层下脑梗死患者脑血氧水平依赖信号的变化。收集10例脑梗死患者的亚急性期和慢性期静息态功能磁共振成像数据,并选择10名年龄、性别匹配的健康志愿者作为对照组,计算受试者的fALFF值,观察患者在不同时期fALFF相对正常人升高和降低的区域。结果 与对照组相比,脑梗死的亚急性期患侧楔前叶、扣带回前部及双侧前额皮质内侧的fALFF降低,双侧上纵束区域的fALFF显著降低;边缘叶fALFF信号紊乱而健侧杏仁核fALFF升高;双侧额下回、直回、颞上回、颞中回、颞下回、梭状回和患侧颞横回fALFF升高;慢性期双侧楔前叶fALFF升高。结论 fALFF功能磁共振成像技术可对脑梗死的脑功能损伤和预后提供有价值的信息。     

完全性脊髓损伤亚急性期脑运动控制功能变化的功能磁共振研究

目的 探讨完全性脊髓损伤患者脑运动控制功能的变化情况。方法 2017年1月至2019年1月,病程3~6个月完全性脊髓损伤患者11例与健康人12例,在试图/实际运动、意象运动(MI)任务下行功能磁共振成像(fMRI)扫描,观察不同运动任务引发激活效应的空间分布和信号强度。结果 患者试图运动时的脑激活区域显著多于健康人实际运动时的激活区域,包括双侧初级感觉/运动皮质(S1/M1)、辅助运动区(SMA)、外侧苍白球(PA)、小脑、左侧丘脑和壳核等。健康人意象运动的比较,患者激活簇主要存在于右M1、SMA、背侧运动前区(PMd)、左SMA、岛叶和基底核。患者试图运动比意象运动在左M1、双SMA、扣带回运动区和右小脑诱发更多的兴奋。结论 亚急性期完全性脊髓损伤患者执行运动任务时,M1、SMA的兴奋模式基本正常,顶叶和小脑等感觉运动整合区域激活增加,提示发生适应性重组。     

Temporal dynamics of basal ganglia response and connectivity during verbal working memory

Research on the neural basis of working memory (WM) has generally focused on neocortical regions; comparatively little is known about the role of subcortical structures. There is growing evidence that the basal ganglia are involved in WM, but their contribution to different component processes of WM is poorly understood. We examined the temporal dynamics of basal ganglia response and connectivity during the encoding, maintenance and response phases of a Sternberg WM task. During the encoding and maintenance phases, WM-load-dependent activation was observed in the left anterior caudate, anterior putamen and globus pallidus; activation in the right anterior caudate was observed only during the maintenance phase. During the response phase, the basal ganglia were equally active in both the high-load and low-load WM conditions. Caudate and putamen activations were primarily localized to the (rostral) associative parts of the basal ganglia, consistent with the putative role of these regions in cognitive processing. Effective connectivity analyses revealed increased WM-load-dependent interaction of the left anterior caudate with the left posterior parietal cortex during all three phases of the task; with the visual association cortex, including the fusiform gyrus and inferior temporal gyrus, only during the encoding phase; with the ventrolateral prefrontal cortex during the encoding and maintenance phases; with the pre-supplementary motor area during the maintenance and response phases; and with the dorsolateral prefrontal and anterior cingulate cortices only during the response phase. Taken together with known neuroanatomy of the basal ganglia, these results suggest that the anterior caudate helps to link signals in distinct functional networks during different phases of the WM task. Our study offers new insight into the integrative and adaptive role of the basal ganglia in higher cognitive function.     

首发精神分裂症患者威斯康星卡片分类测验中的脑功能障碍研究

目的:探讨首发未服药精神分裂症患者进行威斯康星卡片分类测验(WCST)操作时的脑功能状态特点。方法:20名健康受试者(对照组)和20名首发未服药精神分裂症患者(患者组)操作WCST和颜色卡片分类测验(CCST)时进行脑功能磁共振成像(fMRI),比较2组激活脑区的激活体积。结果:对照组WCST和CCST功能图像相减获得的脑活动功能图像显示,激活主要分布在双侧前额叶,尤其是背外侧部以及顶叶后下部皮质和前扣带回。患者组WCST操作成绩较对照组差,有显著性差异(P<0.01)。与对照组相比,患者组的左侧前额叶背外侧部、左前扣带回皮质激活低下,左顶叶后下部皮质激活增加(P<0.01或0.05)。结论:双侧前额叶,尤其是背外侧部,以及顶叶后下部皮质和前扣带回皮质参与WCST操作的高级认知过程。精神分裂症患者在未治疗前就存在执行功能缺陷,其前额叶和扣带回功能低下,可能与患者执行功能障碍相关;后顶叶皮质功能亢进,可能对前额叶功能低下有补偿作用。     

经典三叉神经痛患者脑局部自发活动的静息态功能MRI

目的 观察经典三叉神经痛（CTN）患者静息状态下脑局部自发活动的改变。方法 对27例CTN患者（CTN组）和27名健康对照者（对照组）行静息态脑功能MRI数据采集,采用局部一致性（ReHo）数据分析方法获得CTN组ReHo差异脑区,并对组间差异脑区ReHo值分别与患者视觉模拟评分（VAS）和病程行相关性分析。结果 与对照组比较（P<0.05,高斯随机场校正）,CTN患者双侧初级感觉运动皮层,右侧辅助运动区、颞下皮层和小脑,左侧丘脑、边缘叶/海马旁回和颞上/中皮层ReHo值增高;双侧前额皮层/眶额皮层和脑岛,右侧额内侧皮层和颞上皮层,左侧前扣带回、缘上回和小脑ReHo值减低。右额内侧皮层ReHo值与病程呈负相关（r=-0.45,P=0.03）;左侧初级感觉运动皮层ReHo值与VAS评分（r=0.46,P=0.02）呈正相关。结论 CTN患者存在疼痛相关功能脑区自发功能活动一致性的异常,有助于对CTN发生机制的理解。     

A role of the basal ganglia and midbrain nuclei for initiation of motor sequences

The mesial premotor cortex is crucial for planning sequential procedures and movement initiation. With event-related (ER) functional magnetic resonance imaging (fMRI) it has been possible to separate mesial premotor activation before, during, and after self-initiated movements and, thereby, to distinguish advance planning from execution. The mesial premotor cortex is part of distributed cortico-basal ganglia-thalamo-cortical networks but, to date, the subcortical contributions to self-initiated movements are far less well understood. Using ER fMRI at 3T in 12 right-handed male volunteers, we studied the subcortical activation preceding an automated four-digit finger sequence that was either self-initiated or triggered externally by a visual cue. Beyond typical cortical activation increases in fronto-parietal regions, both initiation modes induced consistent subcortical activation in basal ganglia, midbrain (substantia nigra), and ipsilateral cerebellum. The planning phase of the internally initiated condition, when contrasted with the externally triggered condition, was associated with enhanced activity in frontal regions (mesial premotor cortex/rostral cingulate zone, dorsolateral prefrontal cortex), parietal regions (precuneus, inferior parietal cortex, encroaching onto V5/MT), insula, contralateral anterior putamen and midbrain (bilateral red nucleus/subthalamic nucleus). These data demonstrate the impact of initiation mode on planning-related activity in the ventral basal ganglia and interconnected midbrain nuclei, thereby stressing the crucial role of distributed cortico-basal ganglia-thalamo-cortical networks for self-initiated automated motor repertoires. Involvement of the substantia nigra during planning, as shown here, indicates dopaminergic gating of motor sequences.     

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。     

慢性梗阻性肺部病变患者脑皮质MRI形态学初步研究

目的研究应用基于体素的形态学分析(VBM)方法,观察慢性梗阻性肺部病变(COPD)患者的大脑皮质变化。材料与方法搜集在住院中的COPD患者(患者组)25例和年龄、性别、文化背景等相似的志愿者(对照组)25例进行肺功能、精神状态检查及血气分析。二组均行3D T1WI检查,采用VBM、FSL分析软件(簇体积减少70体素)。应用一般线性模型进行统计学分析,计算两组的全脑灰质总体积,基于体素比较两组全脑灰质各个体素体积的差异。结果COPD患者日常生活活动性、简易精神状态测试、视觉重建及数字记忆测试预测值明显低于正常人。患者额叶的双侧眶回、双侧额下回三角区(Broca区),以及双额内側回、右侧前岛回及深部核团等局部灰质体积较正常对照组减少(P值均0.01)。以统计学t值最大的体素在MNI中的坐标值分析,萎缩最明显的Brodmann脑区主要有47脑区(额上叶皮层)、双侧的13脑区(岛叶皮层)、22脑区(颞上回),及双侧的32脑区(前上扣带回皮层)、24脑区(前下扣带回皮质)。结论COPD患者的多个脑区可出现皮层体积的减少。损伤区域主要涉及前额叶皮质,以及双额内側回、右侧前岛回。与阻塞性睡眠呼吸暂停、先天性中枢呼气不足综合征以及高海拔居民的脑损伤部位相一致。     

fMRI during natural sleep as a method to study brain function during early childhood

Many techniques to study early functional brain development lack the whole-brain spatial resolution that is available with fMRI. We utilized a relatively novel method in which fMRI data were collected from children during natural sleep. Stimulus-evoked responses to auditory and visual stimuli as well as stimulus-independent functional networks were examined in typically developing 2-4-year-old children. Reliable fMRI data were collected from 13 children during presentation of auditory stimuli (tones, vocal sounds, and nonvocal sounds) in a block design. Twelve children were presented with visual flashing lights at 2.5 Hz. When analyses combined all three types of auditory stimulus conditions as compared to rest, activation included bilateral superior temporal gyri/sulci (STG/S) and right cerebellum. Direct comparisons between conditions revealed significantly greater responses to nonvocal sounds and tones than to vocal sounds in a number of brain regions including superior temporal gyrus/sulcus, medial frontal cortex and right lateral cerebellum. The response to visual stimuli was localized to occipital cortex. Furthermore, stimulus-independent functional connectivity MRI analyses (fcMRI) revealed functional connectivity between STG and other temporal regions (including contralateral STG) and medial and lateral prefrontal regions. Functional connectivity with an occipital seed was localized to occipital and parietal cortex. In sum, 2-4 year olds showed a differential fMRI response both between stimulus modalities and between stimuli in the auditory modality. Furthermore, superior temporal regions showed functional connectivity with numerous higher-order regions during sleep. We conclude that the use of sleep fMRI may be a valuable tool for examining functional brain organization in young children.