运动准备和运动执行活动空间分布的功能磁共振成像研究

目的：利用功能磁共振成像技术(fMRI)，研究大脑皮质运动系统运动准备和执行活动的空间分布。方法：采用组块设计，分别对受试者执行实际运动和想象运动时的脑活动进行fMRI扫描，并运用多重回归分析和一般线性检验相结合的方法对运动准备和执行成分的空间分布进行分析。结果：大脑皮质运动系统各运动相关区均不是单一功能区，而是同时参与运动准备和执行两种成分；这两种成分各脑区的分布也不是均一的或者杂乱无章的，而是呈特征性梯度分布：其中辅助运动区(SMA)和运动前区(PMC)自前至后、后顶叶皮质(PPC)自后至前，其参与运动准备的程度越来越低，参与运动执行的程度越来越高。结论：组成大脑皮质运动系统的各随意运动脑区都不是孤立的功能单元，而是一个个同时包含运动执行和准备成分、并具有一定层次的功能子系统；大脑皮质运动系统实际上就是由这些功能上紧密相连的并行加工的子系统组成。     

磁共振观察运动准备与执行的脑功能分布

目的 探索运动指令与运动执行的脑功能区空间分布.方法 被试者为15名健康大学生,根据屏幕上出现的指令,分别进行运动准备和手指对指运动,磁共振采集数据,以最大峰值作为聚类依据,自编聚类程序,对作业活动脑区进行聚类统计处理.结果 在M1区出现大面积的运动激活,且有少量运动准备活动出现;发现SMA、PPC等辅助运动区有较大面积运动准备激活,也有少量运动执行活动的脑激活.在运动脑区,两种功能活动的空间分布清晰.结论 M1、SMA、PPC等脑区并非单一脑功能区,而是多功能混合脑区.     

人脑运动皮层功能磁共振成像研究

目的采用功能用磁共振成像（fMRI）回波平面（EPI）技术,研究人脑运动皮质血氧水平依赖（BOLD）的功能磁共振成像。方法27名正常健康志愿者,右手挤压橡皮圈,在运动和静止两种对比条件下,采集运动皮层的回波平面图像（BOLD-fMRI）。分析运动状态和非运动状态信号对比的脑功能图像。结果fMRI图像显示运动刺激下脑功能活动激活区主要位于对侧感觉运动皮质区、辅助运动区等。结论fMRI可用于研究活体人脑各功能区的活动,fMRI可对运动刺激下的人脑运动皮质进行初步定位。     

脑卒中后运动功能康复的功能磁共振成像研究进展

脑卒中后约有3／4以上患者遗留不同程度的运动功能障碍,重度致残者约占10％以上。近年研究表明,脑组织具有可塑性,在脑卒中发生后进行大脑运动功能重组,经过早期、系统的康复治疗,可以提高患者的生活能力,早日重返社会。     

脑缺血性卒中患者运动功能康复的功能性磁共振成像研究

目的利用功能性磁共振成像（fMRI）技术研究急性期缺血性脑卒中患者（以下简称急性期患者）运动相关皮质的激活情况，并探讨脑卒中后脑功能重组特点及其与肢体运动功能恢复的关系。方法采用GEI．5T双梯度16通道磁共振成像系统，对9例急性期患者和9例健康志愿者行Bold—fMRI检查。fMRI检查以被动对指运动（以下简称运动）为刺激任务，所有数据采用SPM2软件包进行离线后处理。比较健康志愿者与急性期患者fMRI结果的异同点，计算脑激活区体积和单侧化指数（LI），考察急性期患者患手运动LI值与患手运动功能的关系。结果健康志愿者单手运动激活对侧感觉运动皮质（SMC）、双侧辅助运动区（SMA）。急性期患者患手运动时同侧半球脑激话增多，健手运动的fMRI结果与健康志愿者基本一致。LI值也进一步确定，急性期患者患手运动时同侧半球脑激活增多。统计学分析表明，急性期患者患手运动的LI值与患手运动功能呈正相关。结论fMRI检查能客观地反映急性期患者运动相关皮质改变，提示存在脑功能代偿与重组。急性期患者患手运动LI值与患手运动功能呈正相关，提示fMRI是研究缺血性脑卒中后肢体运动功能康复与脑功能重组之间关系的一种有效工具。     

磁共振脑功能成像

磁共振功能成像 (funtional magnetic resonance imaging, fMRI)是一种崭新的成像方法,近年来被广泛地用于脑功能研究,特别是大脑功能区的划分,它突破了既往从解剖学、生理学、病理生理学角度对脑实施研究的状态,开辟了脑功能研究的新领域 [1]。 1 MR脑功能成像原理 MR脑功能成像并不能直接检测神经元活动,而是通过 MR信号反映脑血氧饱和度及血流量的变化,从而间接反映神经元的能量消耗,在一定程度上反映神经元活动情况,达到脑功能成像的目的。神经元活动增强时,脑功能区皮层流过的血流量增加,而细胞耗氧增加量并不明显,二…     

脑活动功能磁共振成像研究进展

本文介绍了人脑活动功能磁共振成像(fMRI)的生物物理基础研究的现状和关键技术的进展,综述了这些技术在人脑功能研究和临床疾病诊疗中的应用和发展前景.     

顶叶区病变手指运动的脑功能磁共振成像

磁共振功能成像(functionalmagneticresonanceimaging,fMRI)是通过一定的刺激使大脑皮层各功能区在磁共振设备上成像的方法,它结合了功能、影像和解剖三方面的因素,是一种在活体人脑定位各功能区的有效方法。它已经被用于认知科学、心理学、药物滥用等多个研究领域[1～3]。尤其是对神经肿瘤学方面的应用已越来越受到重视[4,5]。本文对2001年6月～2003年3月在我院手术治疗的15例顶叶区病变患者的脑功能磁共振成像图像进行回顾性报道。1　资料与方法11　一般资料在15例顶叶区病变患者中,男性12例,女性3例,年龄最小为46岁,最大58岁,平均年龄5…     

神经肌肉电刺激诱发健康年轻人手部运动时脑功能性磁共振成像研究

目的观察神经肌肉电刺激（NMES）诱发健康年轻人手部运动时的脑功能性磁共振成像（fMRI）,探讨NMES对中枢神经系统的影响。 方法6位健康志愿者参与本项研究,其中男5例,女1例,年龄（25.17±3.43）岁,在NMES的作用下引出手部腕背伸和拇外展动作,刺激电流的参数为：频率30 Hz,脉宽0.2 ms,双向方波,通电∶断电＝2 s∶2 s,波升∶波降＝1∶1,电流强度以受试者可耐受的最大强度为准。通过fMRI技术获得脑功能变化图像,利用统计参数图2（SPM2）软件进行图像分析,得出激活脑区的定位信息。 结果NMES诱发健康人的手部运动时,主要激活对侧及同侧运动皮质和躯体感觉皮质。 结论健康人NMES诱发手部运动可以引起大脑运动皮质及躯体感觉皮质的兴奋性改变反应。     

Brain activity during automatic semantic priming revealed by event-related functional magnetic resonance imaging

Semantic priming occurs when a subject is faster in recognising a target word when it is preceded by a related word compared to an unrelated word. The effect is attributed to automatic or controlled processing mechanisms elicited by short or long interstimulus intervals (ISIs) between primes and targets. We employed event-related functional magnetic resonance imaging (fMRI) to investigate blood oxygen level dependent (BOLD) responses associated with automatic semantic priming using an experimental design identical to that used in standard behavioural priming tasks. Prime-target semantic strength was manipulated by using lexical ambiguity primes (e.g., bank) and target words related to dominant or subordinate meaning of the ambiguity. Subjects made speeded lexical decisions (word/nonword) on dominant related, subordinate related, and unrelated word pairs presented randomly with a short ISI. The major finding was a pattern of reduced activity in middle temporal and inferior prefrontal regions for dominant versus unrelated and subordinate versus unrelated comparisons, respectively. These findings are consistent with both a dual process model of semantic priming and recent repetition priming data that suggest that reductions in BOLD responses represent neural priming associated with automatic semantic activation and implicate the left middle temporal cortex and inferior prefrontal cortex in more automatic aspects of semantic processing.     

Acute opioid effects on human brain as revealed by functional magnetic resonance imaging

Functional magnetic resonance imaging has been widely used to study brain activation induced either by specific sensory stimulation or motor or cognitive task performance. We demonstrate that functional magnetic resonance imaging can provide information of brain regions involved in opioid-induced central nervous system effects. The reproducibility of the responses in the predefined regions of interest was confirmed by repeated boluses of ultra-short acting mu-opioid receptor agonist remifentanil and saline. We report spatially and temporally detailed information after remifentanil administration. Areas rich in mu-opioid receptors showed strong activations, whereas primary somatosensory cortex that has the lowest density of mu-opioid receptors showed negligible activation. The cingulate, orbitofrontal, posterior parietal and insular cortices, and amygdala showed activation, which was temporally closely related to most subjective sensations that were strongest at 80 to 90 s after drug administration. These areas belong to a circuitry that modulates the affective experience of sensory stimuli.     

应用功能性磁共振成像技术探讨针刺三阴交穴对脑功能的调节作用

目的观察手捻针刺三阴交穴对脑组织功能性磁共振成像（fMRI）的影响，分析针刺三阴交穴对大脑不同区域功能的调节作用，从现代科学角度对针刺三阴交穴的可能作用机理进行初步探讨。方法应用磁共振成像系统，对8名健康右利手志愿者接受针刺右侧三阴交穴期间的功能活动进行全脑扫描，获得针刺三阴交穴的脑功能激活图。8名自愿者的数据经过空间平滑、头动矫正等处理后进行平均化，通过反卷积计算每个体素的信号改变，定义P〈0．001为差异具有统计学意义。结果针刺右侧三阴交穴可激活左右额内侧回、右额中回、左额下回、双侧中央旁小叶、左右中央前回、左右中央后回、左侧顶下小叶、双侧楔前叶、右颞中回、右扣带回、右扣带后回、双侧颞上回、双侧颞横回、双侧岛叶和双侧丘脑。结论针刺三阴交穴可激活额、顶、颞叶皮质以及扣带回、楔前叶、岛叶、丘脑，可能是其治疗泌尿、生殖、消化系统疾病和下肢神经痛、瘫痪，以及改善精神和睡眠状态的作用机制。针刺三阴交穴能引起双侧特定脑皮质的反应，进一步证实穴位与脑皮质相应代表区之间存在相关性。     

听觉脑功能磁共振成像

听觉脑功能磁共振成像是磁共振功能成像(functionalmagneticresonanceimaging,fMRI)的一种,fMRI是一种安全的影像学检查手段,在完全无创的条件下对人脑进行功能分析,一次成像可同时获得解剖与功能影像,而且对人体无辐射损伤。尽管fMRI技术和方法还在不断发展和完善,但其可靠性和实用性是不容置疑的。它对听觉障碍患者的术前诊断、手术计划的制定、术后患者康复程度的评估,将会发挥越来越重要的作用。     

Item analysis in functional magnetic resonance imaging

Behavioral and neuroimaging studies of cognition frequently test hypotheses regarding mental processing of different stimulus categories (e.g. verbs, faces, animals, scenes, etc.). The conclusions of such studies hinge upon the generalizability of their findings from the specific stimuli used in the experiment to the category as a whole. This type of generalizability is explicitly tested in behavioral studies, using "item analysis". However, generalizability to stimulus categories has up until now been assumed in neuroimaging studies, without employing item analysis for statistical validation. Here we apply item analysis to a functional magnetic resonance imaging study of nouns and verbs, demonstrating its theoretical importance and feasibility. In the subject-wise analysis, a left prefrontal and a left posterior-temporal region of interest showed putative grammatical class effects. An item-wise analysis revealed, however, that only the left posterior-temporal effect was generalizable to the stimulus categories of nouns and verbs. Taken together, the findings of the subject- and item-wise analyses suggest that grammatical-class effects in the left prefrontal cortex depend on the particular word stimuli used, rather than reflecting categorical differences between nouns and verbs. This empirical example illustrates that item analysis not only is sufficiently powered to detect task relevant changes in BOLD signal but also can make theoretically important distinctions between findings that generalize to the item populations, and those that do not.     

Interhemispheric neuroplasticity following limb deafferentation detected by resting-state functional connectivity magnetic resonance imaging (fcMRI) and functional magnetic resonance imaging (fMRI)

Functional connectivity magnetic resonance imaging (fcMRI) studies in rat brain show brain reorganization following peripheral nerve injury. Subacute neuroplasticity was observed 2 weeks following transection of the four major nerves of the brachial plexus. Direct stimulation of the intact radial nerve reveals a functional magnetic resonance imaging (fMRI) activation pattern in the forelimb regions of the sensory and motor cortices that is significantly different from that observed in normal rats. Results of this fMRI experiment were used to determine seed voxel regions for fcMRI analysis. Intrahemispheric connectivities in the sensorimotor forelimb representations in both hemispheres are largely unaffected by deafferentation, whereas substantial disruption of interhemispheric sensorimotor cortical connectivity occurs. In addition, significant intra- and interhemispheric changes in connectivities of thalamic nuclei were found. These are the central findings of the study. They could not have been obtained from fMRI studies alone—both fMRI and fcMRI are needed. The combination provides a general marker for brain plasticity. The rat visual system was studied in the same animals as a control. No neuroplastic changes in connectivities were found in the primary visual cortex upon forelimb deafferentation. Differences were noted in regions responsible for processing multisensory visual-motor information. This incidental discovery is considered to be significant. It may provide insight into phantom limb epiphenomena.     

功能磁共振在神经外科中的应用

功能磁共振(fMRI)是一种被广泛接受的成像手段,近年来已用于多种临床实践中,特别是在指导神经外科手术方面有了很大的进展.本文就fMRI基本原理和技术及其在有效性评估、指导神经外科手术和术后患者随访方面的作用予以综述.     

功能磁共振成像临床应用及进展

近几十年来,多种模态的功能磁共振技术飞速发展,为临床医学的发展产生了重要影响,也为精神影像学的发展提供了重要手段,极大的深化了人类对神经系统疾病和疾病的认知.本文就功能磁共振的成像及图像后处理技术,及其在反映疾病亚临床阶段的功能改变、实时活体的个体化脑功能定位、探索中枢神经系统药物机制等方面的临床应用和进展进行了述评,同时阐明其技术缺陷及未来发展方向.     

胎盘功能磁共振成像研究进展

胎盘是维持胎儿在子宫内发育的重要器官。MRI越来越多地用于胎儿及胎盘的解剖成像。随着影像技术的发展,功能MRI广泛应用于科研及临床,亦是评估胎盘功能重要的工具。本文对胎盘功能MRI的主要研究进展进行综述。