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1.
Movement-associated cortical changes have been shown in several neurological conditions and were found to be associated to the extent of brain and cord damage. Devic's neuromyelitis optica (DNO) is characterized by a severe involvement of the cord and optic nerve, with sparing of the brain. To assess the actual role of cord pathology on the pattern of movement-associated cortical recruitment, we obtained functional magnetic resonance imaging (fMRI) from patients with DNO and investigated whether the extent of brain activation is correlated with the extent of cervical cord damage. We studied 10 right-handed DNO patients and 15 sex- and age-matched healthy controls. The MRI assessment consisted of the following: (a) fMRI during repetitive flexion extension of the last four fingers of the right and left hand, (b) brain and cervical cord conventional MRI, and (c) cervical cord magnetization transfer (MT) MRI. Compared to controls and for both tasks, DNO patients had an increased recruitment of several regions of the sensorimotor network (primary sensorimotor cortex, postcentral gyrus, middle frontal gyrus, rolandic operculum, secondary sensorimotor cortex, precuneus, and cerebellum) and of several other regions mainly in the temporal and occipital lobes, such as MT/V5, the fusiform gyrus, the cuneus, and the parahippocampal gyrus. For both tasks, strong correlations (r values ranging from -0.76 to -0.85) were found between relative activations of cortical sensorimotor areas and the severity of cervical cord damage. This study shows an abnormal pattern of movement-associated cortical activations in patients with DNO, which extends beyond the 'classical' sensorimotor network and also involves visual areas devoted to motion processing. The correlation found between fMRI changes and the extent of cord damage suggests that such functional cortical changes might have an adaptive role in limiting the clinical outcome of DNO structural pathology.  相似文献   

2.
Blood oxygenation level dependent contrast functional MRI (BOLD-fMRI) has been used to define the functional cortices of the brain in preoperative planning for tumor removal. However, some studies have demonstrated false-negative activations in such patients. We compared the evoked-cerebral blood oxygenation (CBO) changes measured by near-infrared spectroscopy (NIRS) and activation mapping of BOLD-fMRI in 12 patients with brain tumors who had no paresis of the upper extremities. On the nonlesion side, NIRS demonstrated a decrease in deoxyhemoglobin (Deoxy-Hb) with increases in oxyhemoglobin (Oxy-Hb) and total hemoglobin (Total-Hb) during a contralateral hand grasping task in the primary sensorimotor cortex (PSMC) of all patients. On the lesion side, NIRS revealed a decrease in Deoxy-Hb in five patients (Deoxy-decrease group), and an increase in Deoxy-Hb in seven patients (Deoxy-increase group); the Oxy-Hb and Total-Hb were increased during activation in both groups, indicating the occurrence of rCBF increases in response to neuronal activation. BOLD-fMRI demonstrated clear activation areas in the PSMC on the nonlesion side of all patients and on the lesion side of the Deoxy-decrease group. However, in the Deoxy-increase group, BOLD-fMRI revealed only a small activation area or no activation on the lesion side. Intraoperative brain mapping identified the PSMC on the lesion side that was not demonstrated by BOLD-fMRI. The false-negative activations might have been caused by the atypical evoked-CBO changes (i.e. increases in Deoxy-Hb) and the software employed to calculate the activation maps, which does not regard an increase of Deoxy-Hb (i.e., a decrease in BOLD-fMRI signal) as neuronal activation.  相似文献   

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目的:用血氧水平依赖性磁共振功能成像(BOLD-fMRI)技术研究KCl诱导猫脑模型的播散性皮层抑制(SCD)。方法:雌猫6只,双侧额窦开颅并充填琼脂糖凝胶,两侧上侧裂回上方开颅,以备分别注入KCl凝胶和生理盐水凝胶。在1.5T场强下分别行静息期、KCl刺激期及对侧生理盐水刺激期BOLD-fMRI采集。结果:KCl刺激区上侧裂回及邻近边缘回脑皮层可见脑功能激活区者5例,并播及到同侧边缘回后部,而对侧大脑半球均无脑激活区。感兴趣区时间-信号强度曲线显示注入KCl后,fMRI信号立即显著增高,并维持于高水平较长时间。结论:BOLD-fMRI能准确检测出SCD伴发的神经血管耦联现象—脑血流量的变化,是研究SCD的可靠方法。  相似文献   

5.
目的 探讨结合型局灶性脑皮层发育不良(FCDⅢ型)的MRI影像表现。方法 回顾性分析经临床、手术及病理证实的158例符合FCDⅢ型的MRI影像资料,总结FCDⅢ型的异常影像表现特点。结果 158例FCDⅢ型病灶中,有147例位于颞叶(比例约为93.0%),120例FCDⅢa型的FCD病灶均为前颞叶脑组织。113例FCDⅢ型中FCD病灶影像异常,阳性率约71.5%,其中FCDⅢa、FCDⅢb型、FCDⅢc型、FCDⅢd型影像阳性率分别为81.7%、47.8%、50%、11.1%。FCD病灶异常影像表现为病灶区灰白质分界稍模糊(83.2%),皮层T_2FLAIR序列信号轻度增高(69.9%),皮层轻度增厚(49.6%),皮层T2WI序列信号略有增高(20.4%),局部脑叶萎缩(14.2%)等影像特点。结论 FCDⅢ型中FCD病灶影像异常表现轻微,常为多个轻度异常影像相互存在,发生部位以颞叶为主,FCDⅢa型发病率最高,故发生于颞叶的海马硬化、肿瘤、血管畸形等病变时,需要排除存在FCDⅢ型可能,尤其是在发现海马硬化时,要注意对前颞叶轻微异常影像表现提高警惕,对提高癫痫外科术前及预后评估有重要意义。  相似文献   

6.
目的:应用血氧水平依赖的功能MRI(BOLD-fMRI),探索帕金森病(PD)患者静息态脑功能可能存在的异常。材料与方法对68例PD患者和36例健康志愿者进行静息态BOLD-fMRI检查。分析PD组与正常对照组标准化脑功能低频振荡幅度(mALFF)的差异。结果与正常对照组比较,PD组在双侧辅助运动区、中后扣带回、楔前叶、海马、海马旁回、外侧苍白球、背侧丘脑、小脑前叶以及右侧局部初级运动皮层、岛叶、尾状核、壳核、小脑后叶等广泛区域mALFF值显著减低(P〈0.05,AlphaSim校正),在双侧前额叶、顶叶及颞叶的广泛外侧皮层、左侧枕叶初级视觉皮层等区域mALFF值显著增高(P〈0.05,AlphaSim校正)。结论 PD患者静息态脑功能存在广泛异常,主要表现为PD患者在运动调节相关脑区、默认网络关键节点、边缘系统等部位神经元活动减弱,在前额叶、顶叶、颞叶的广泛外侧皮层以及初级视觉皮层等部位神经元活动增强。  相似文献   

7.
目的探讨原发性全面强直阵挛癫痫(generalized tonic-clonic seizure,G T C S)发作间期静息态下大脑和小脑之间功能连通性的改变特点。材料与方法对19例原发性GTCS患者(GTCS组)及22名年龄、性别、受教育程度、利手等相匹配的健康对照组志愿者(HC组)采集静息态功能磁共振数据,计算并比较两组被试全脑低频振幅(amplitude of low-frequency fluctuations,ALFF)值,分别以大脑(小脑)ALFF差异区为种子区计算其与小脑(大脑)所有体素之间静息态功能连接(resting state functional connectivity,rs FC)并进行组间比较,提取组间显著差异脑区ALFF/rs FC值与患者国立医院癫痫严重程度量表(national hospital seizure severity scale,NHS3)评分做相关分析。结果相对于正常对照组,GTCS组右侧楔前叶、左侧额中回ALFF值显著升高,而右侧海马、右侧小脑脚2区、左侧小脑4/5区ALFF值显著降低;以各大脑(小脑)ALFF差异区为种子区域,GTCS患者组左侧小脑8区、右侧小脑4/5区rs FC值显著升高(左侧额下回、右侧颞中回rs FC值显著降低);GTCS患者组NHS3评分与左侧小脑8区rs FC值之间呈显著正相关(r=0.48,P=0.036),与右侧颞中回rs FC值之间呈显著负相关(r=-0.34,P=0.042)。结论 GTCS发作间期存在大脑和小脑之间静息态功能连通性异常,这些功能连通性的异常可能与GTCS患者的发病机理和临床表现有关。  相似文献   

8.
Cortical functional changes, with the potential to limit the functional consequences of tissue injury, have been shown in patients with multiple sclerosis (MS). In this study, we assessed the influence of MS-related tissue damage of the brain portion of the left pyramidal tract on the corresponding movement-associated patterns of cortical recruitment in a large sample of MS patients when performing a simple motor task with their fully normal functioning right upper limbs. We investigated 76 right-handed patients with definite MS. In each subject, functional magnetic resonance imaging (fMRI) was acquired during the performance of a simple motor task with the dominant, right upper limb. During the same session, dual-echo, magnetization transfer (MT) and diffusion tensor (DT) MRI sequences were also obtained to quantify the extent and the severity of pyramidal tract damage. Lesions along the left pyramidal tract were identified in 43 patients. Compared to patients without pyramidal tract lesions, patients with such lesions had more significant activations of the contralateral primary sensorimotor cortex (SMC), secondary sensorimotor cortex (SII), inferior central sulcus, and cingulate motor area (CMA). They also showed more significant activations of several regions of the ipsilateral hemisphere, including the primary SMC and the precuneus. In these patients, T2 lesion load of left pyramidal tract was correlated with the extent of activation of the contralateral primary SMC (r2 = 0.25, P < 0.0001), whereas no correlations were found between the extent of fMRI activations and the severity of intrinsic lesion damage, as well as with left pyramidal tract normal-appearing white matter damage. This study shows that, in patients with MS, following injury of the motor pathways, there is an increased recruitment of a widespread sensorimotor network, which is likely to contribute to limit the appearance of overt clinical deficits.  相似文献   

9.
It has been confirmed that some kinds of what are called memory strategies dramatically improve the performance of memory recall. However, there has been no direct research to examine changes in brain activity associated with the use of the method of loci within individuals. In the present study, using fMRI, we compared brain activations before and after instruction in the method of loci during both the encoding and recall phases. The resulting behavioral data showed that the use of the method of loci significantly increased scores for memory recall. The imaging data showed that encoding after instruction in the method of loci, relative to encoding before it, was associated with signal increases in the right inferior frontal gyrus, bilateral middle frontal gyrus, left fusiform gyrus, and bilateral lingual gyrus/posterior cingulate gyrus. Comparison of recall after instruction in the method of loci with that before it showed significant activation in the left parahippocampal gyrus/retrosplenial cortex/cingulate gyrus/lingual gyrus, left precuneus, left fusiform gyrus, and right lingual gyrus/cingulate gyrus. The present study demonstrated the changes in brain activation pattern associated with the use of the method of loci; left fusiform and lingual activity was associated with both the encoding and recall phases, bilateral prefrontal activity with the encoding phase, and activity of the posterior part of the parahippocampal gyrus, retrosplenial cortex, and precuneus with the recall phase. These findings suggest that brain networks mediating episodic encoding and retrieval vary with how individuals encode the same stimuli.  相似文献   

10.
目的:研究抑郁患者自我注意的大脑皮层功能变化,探讨自我注意是否与抑郁情绪相关。方法:选取8名抑郁患者和9名健康志愿者进行fMRI。采用BOLD组块设计,受试者接受与自我注意相关的3种任务刺激,原始数据经SPM8脑功能MR软件包处理,获得受试者的脑激活图,并进行对照研究,分析抑郁患者和健康志愿者脑激活空间分布的差异。结果:三种靶刺激条件下,抑郁患者比正常志愿者均存在较多激活脑区。抑郁患者在“我”靶刺激条件下脑区激活显著多于“*”和“他”靶刺激条件。结论:抑郁患者可能存在自我注意偏向,抑郁情绪可能与自我注意相关。  相似文献   

11.
电针周围性面瘫患者穴位的功能磁共振成像研究   总被引:3,自引:0,他引:3  
目的 探讨功能磁共振成像(fMRI)研究电针周围性面瘫患者不同穴位时脑功能区变化.方法 将18例左侧周围性面瘫患者随机分为3组,分别电针左侧地仓穴(6例)、左侧合谷穴(6例)、左侧后溪穴(6例),同时行全脑fMRI 扫描.以SPM 软件进行图像后处理,t检验(P<0.05)分析得出电针不同穴位的脑功能图像. 结果电针左侧地仓穴、左侧合谷穴信号降低区:双侧额中回,左扣带回;信号升高区:右侧中央前回,双侧中央后回,左侧颞上回,右侧脑岛.电针左侧后溪信号降低区:双侧额下回,左侧豆状核,右侧颞中回,右侧小脑扁桃体;信号升高区:右侧尾状核头,右侧扣带回,脑干,小脑蚓,右侧海马回. 结论 电针周围性面瘫患者合谷穴和地仓穴可引起大脑相应的功能区激活,而电针后溪穴未见和前两者有相似的激活区域,推测穴位与大脑的联系与其所属的经脉有密切联系.  相似文献   

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慢性酒精依赖是一种严重危害患者心理和身体健康的成瘾性疾病,表现为对酒精的过度渴望以及不可控制性摄入。近年MR已广泛用于物质成瘾性研究,尤其对慢性酒精依赖的研究取得了显著进展,对酒精依赖的早期预防、诊断、治疗以及预后评估具有重要意义。本文就慢性酒精依赖患者脑的结构及功能MRI研究进展作一综述。  相似文献   

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The reproducibility of three different aspects of fMRI activations-namely binary activation maps, effect size and spatial distribution of local maxima-was evaluated for an auditory sentence comprehension task with high attention demand on a group of 17 subjects that were scanned on five different occasions. While in the scanner subjects were asked to listen to a series of six short everyday sentences from the CUNY sentence test. Comprehension and attention to the stimuli were monitored after each listen condition epoch by having subjects answer a series of multiple-choice questions. Statistical maps of activation for the listen condition were computed at three different levels: overall results for all imaging sessions, group-level/single-session results for each of the five imaging occasions, and single-subject/single-session results computed for each subject and each scanning occasion independently. The experimental task recruited a distributed bilateral network with processing nodes located in the lateral temporal cortex, inferior frontal cortex, medial BA6, medial occipital cortex and subcortical structures such as the putamen and the thalamus. Reproducibility of these activations at the group level was high (83.95% of the imaged volume was consistently classified as active/inactive across all five imaging sessions), indicating that sites of neuronal activity associated with auditory comprehension can reliably be detected with fMRI in healthy subjects, across repeated measures after group averaging. At the single-subject level reproducibility ranged from moderate to high, although no significant differences were found on behavioral measures across subjects or sessions. This result suggests that contextual differences-i.e., those specific to each imaging session, can modulate our ability to detect fMRI activations associated with speech comprehension in individual subjects.  相似文献   

14.
Zhang JX  Leung HC  Johnson MK 《NeuroImage》2003,20(3):1531-1539
To investigate the involvement of frontal cortex in accessing and evaluating information in working memory, we used a variant of a Sternberg paradigm and compared brain activations between positive and negative responses (known to differentially tax access/evaluation processes). Participants remembered two trigrams in each trial and were then cued to discard one of them and maintain the other one as the target set. After a delay, a probe letter was presented and participants made decisions about whether or not it was in the target set. Several frontal areas--anterior cingulate (BA32), middle frontal gyrus (bilateral BA9, right BA10, and right BA46), and left inferior frontal gyrus (BA44/45)--showed increased activity when participants made correct negative responses relative to when they made correct positive responses. No areas activated significantly more for the positive responses than for the negative responses. It is suggested that the multiple frontal areas involved in the test phase of this task may reflect several component processes that underlie more general frontal functions.  相似文献   

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目的:对1例脑卒中上肢偏瘫患者进行强制性使用运动疗法治疗,同时连续进行动态功能性磁共振成像观察,以探讨大脑功能重组与功能恢复之间的相关性。方法:对患者进行2周的强制性使用运动疗法治疗,使用夹板限制健侧上肢活动2周,每天保持6小时的患侧上肢训练。在治疗前1天、治疗后当天、治疗后2周分别在患者对指运动时进行功能磁共振扫描。结果:与治疗前基线相比,患者上肢Carroll评分提高29.1%,金子翼评分提高18.4%,3个月后随访,Carroll上肢功能评分提高30.6%,金子翼上肢功能评分提高26.2%。对健手限制2周后,其运动功能没有下降。在治疗前,患手运动时使用功能磁共振扫描可以发现对侧中央前后回、对侧额叶前部、同侧大脑皮层中央前回激活;健手运动时,以对侧中央前后回兴奋为主。经过强制性使用治疗后,患手运动时同侧和对侧大脑皮层广泛的激活,健手运动时,大脑对侧中央前后回的兴奋区域明显变小;治疗结束2周后,患侧上肢运动时,患手运动时其同侧和对侧大脑皮层广泛的激活的现象明显降低,激活区集中在对侧的中央前后回,在健手运动时,又重新恢复对侧中央前后回兴奋区域。结论:强制性使用运动疗法可明显提高脑卒中患者上肢运动功能,使用功能性磁共振证明这种变化与大脑可塑性改变相关联,同时限制健侧肢体活动不会影响其运动功能,大脑激活区域的变化为一过性改变。  相似文献   

16.
PurposeMigraine is often accompanied with chronic tinnitus that will affect the cerebral blood flow (CBF) and exacerbate the tinnitus distress. However, the potential relationship between migraine and tinnitus remains unclear. This study will investigate whether aberrant CBF patterns exist in migraine patients with tinnitus and examine the influence of migraine on CBF alterations in chronic tinnitus.Materials and methods Participants included chronic tinnitus patients (n = 45) and non-tinnitus controls (n = 50), matched for age, sex, education, and hearing thresholds. CBF images were collected and analyzed using arterial spin labeling (ASL) perfusion functional magnetic resonance imaging (fMRI). Regions with major CBF differences between tinnitus patients and non-tinnitus controls were first detected. The effects of migraine on tinnitus for CBF alterations were further examined. Correlation analyses illustrated the association between CBF values and tinnitus severity as well as between CBF and severity of migraine.ResultsCompared with non-tinnitus controls, chronic tinnitus patients without migraine exhibited decreased CBF, primarily in right superior temporal gyrus (STG), bilateral middle frontal gyrus (MFG), and left superior frontal gyrus (SFG); decreased CBF in these regions was correlated with tinnitus distress. There was a significant effect of migraine on tinnitus for CBF in right STG and MFG. Moreover, the severity of migraine correlated negatively with CBF in tinnitus patients.ConclusionsChronic tinnitus patients exhibited reduced CBF in the auditory and prefrontal cortex. Migraine may facilitate a CBF decrease in the setting of tinnitus, which may underlie the neuropathological mechanisms of chronic tinnitus comorbid with migraine.  相似文献   

17.
Background: Central pain (CP) is a common symptom in MS. Multiple theories are present about the mechanism of CP. Previous studies suggested that lesion of the spinothalamic tract is a necessary condition for development of CP. No previous study has in detail evaluated the association between the specific site of demyelinations and the presence of CP in MS. Objective: The study aimed to evaluate the location of plaques in MS patients with CP including a group of MS patients without pain as a reference group. Methods: All patients underwent a bedside sensory examination and MRI of the brain and spinal cord. MR imaging was acquired on an 1.5 Tesla MR equipment. A trained neuroradiologist, blinded to pain status, evaluated the MRI. Results: Thirteen MS patients with CP and 10 MS patients without pain were included. Allodynia and/or dysesthesia were more frequent in pain patients (11/13 vs. 1/10, P <0.01). No difference was found in the number of patients with plaques in spinothalamic tract, dorsal column‐medial lemniscus, dorsolateral funiculus, grey substance, thalamus or capsula interna. A non‐significantly lower number of pain patients had lesions in thalamo‐cortical pathways (8/13 vs. 10/10, P =0.027). Conclusions: No association between CP and site of demyelinations was found, although a trend toward a higher prevalence of intact thalamo‐cortical pathways was seen in pain patients. CP was associated with allodynia, suggesting central hyperexcitability.  相似文献   

18.
Functional MRI (fMRI) has not previously been used systematically to investigate brain function in preterm infants. We here describe statistically robust and reproducible fMRI results in this challenging subject group using a programmable somatosensory stimulus synchronized with MR image acquisition which induced well-localized positive blood oxygen level dependent (BOLD) responses contralateral to the side of the stimulation in: 11 preterm infants (median post menstrual age 33 weeks and 4 days, range 29 + 1 to 35 + 3); 6 control infants born at term gestational age; and 18 infants born preterm (median gestational age at birth 30 weeks and 5 days, range 25 + 4 to 36 + 0) but studied at term corrected gestational age. Bilateral signals were identified in 8 of the ex-preterm infants at term age. Anatomical confirmation of appropriate activations was provided with diffusion tensor imaging (DTI) based tractography which identified connecting pathways from the regions of activation through the ipsilateral corticospinal tracts and posterior limb of the internal capsule. These results demonstrate that it is possible to reliably identify positive BOLD signals in the infant brain and that fMRI techniques can also be applied in the study of preterm infants.  相似文献   

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目的:观察正常人单眼水平半视野刺激下视觉皮层的激活形式;探讨fMRI用于评价颞侧偏盲患者初级视觉皮层激活形式的可能性。资料与方法:对13例颞侧偏盲的垂体大腺瘤患者和15名正常志愿者进行组块设计的fMRI实验,所有受试者分别接受左眼颞侧、左眼鼻侧、右眼颞侧和右眼鼻侧视野刺激,刺激内容为水平单侧40°黑白翻转棋盘格,对照内容为黑色屏幕中心的白色“+”。采用1.5T MR扫描仪采集数据,采用SPM 2软件进行后处理,获得对照组各种刺激下的平均激活图,分析患者组视野缺损与初级视觉皮层激活形式之间的对应关系。结果:在排除了扫描过程中头动及噪声影响后,患者组和对照组最终各入组10例。对照组单眼颞侧视野刺激时表现为对侧视觉皮层激活,鼻侧视野刺激时表现为同侧初级视觉皮层激活为主。患者组在接受颞侧视野刺激时双侧视觉皮层均未见激活,而给予鼻侧视野刺激时均表现为同侧视觉皮层激活。结论:正常情况下视野与初级视觉皮层之间存在对应关系,颞侧偏盲患者表现为以对侧初级视觉皮层激活下降为主,fMRI是反映视交叉异常对视觉皮层影响的有效方法。  相似文献   

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