基于fMRI的力量调节速度相关神经兴奋模式的初步研究

目的研究视觉引导的握力运动力量调节速度快慢所激活脑功能区的异同。方法15例正常受试者右手进行四种模式（由视觉反馈增益和力量变化速度两个因素组合而成）握力运动，同时进行BOLD fMRI扫描，比较四种模式脑激活的异同。结果四种模式握力运动均可激活初级躯体感觉运动区（SMC），双侧前运动区（PMC）、辅助运动区（SMA）、小脑、基底节（BG），对侧后顶叶（PPC），Brodmann 40等。其中，随着力量调节速度的提高，SMC激活强度、范围都提高，而BG恰好相反，SMA激活强度提高但范围缩小，小脑表现不明显。结论SMC对力量输出的快速调节作用明显；PPC，PMC参与了将视觉信息转化成力量输出这一过程；BG在快速运动时受到SMC、SMA的制约。     

缺血性脑卒中患者患手主动运动及被动运动时的功能性磁共振研究

目的观察缺血性脑卒中患者患手执行主动及被动运动时的脑激活模式,探讨主动运动和被动运动治疗脑卒中后手功能障碍的中枢机制。 方法对5例左侧大脑皮质下脑卒中患者患手执行主动及被动抓握-释放动作,执行动作期间采用血氧水平依赖性功能性磁共振（BOLD-fMRI）进行脑扫描,利用SPM5软件对上述患者试验数据进行分析,使用XJVIEW toolbox 8.11版软件得出入选患者在上述两种运动状态下的脑激活区分布图,并对其在不同运动状态下的脑激活模式特点进行分析比较。 结果入选患者患手在执行主动运动时其脑激活部位主要位于对侧感觉运动区(SMC)、运动前区(PMC)、双侧小脑及双侧辅助运动区(SMA),另外同侧SMC及PMC区也有轻度激活;激活脑区主要位于对侧大脑及小脑半球。患手执行被动运动时的脑激活部位主要位于双侧SMC、PMC区、双侧小脑、SMA区;激活脑区平均分布于两侧大脑及小脑半球。与患手主动运动比较,患手被动运动时的脑区激活范围较广泛,激活强度也较高。 结论患手执行主动运动和被动运动均可激活脑卒中患者运动相关脑区,提示对脑卒中患者进行主动运动及被动运动均可促进其脑功能重组。     

共济失调患者手运动时脑激活区域的定量分析

目的 利用血氧水平依赖性功能性磁共振成像(BOLD-fMRI)技术,探讨共济失调患者在主动与被动复杂对指运动模式下关键脑功能区激活体积和强度的变化.方法 选取共济失调患者16例作为病例组,另选10名健康志愿者作为正常组.入选者均进行主动与被动复杂对指运动,在这两种运动模式下进行BOLD-fMRl检查,记录相应脑运动功能区的激活体积和强度并进行定量分析.采用共济失调量表(ICARS)对共济失调患者的共济运动进行评分.结果 病例组患手主动运动时,同侧辅助运动区(SMA)激活体积大于正常组同侧手的测定结果,激活强度也高于正常组;同侧小脑的激活体积和激活强度则小于正常组,小脑激活区的出现率也低于正常组.病例组患手主动运动时,同侧小脑激活区的体积、激活强度与共济失调量表评分无相关性.结论 共济失调患者患侧小脑功能下降,而同侧SMA可以发挥代偿作用,临床共济失调量表的评分尚不能准确反映小脑功能情况.     

共济失调患者手运动时脑激活区域的定量分析

目的 利用血氧水平依赖性功能性磁共振成像(BOLD-fMRI)技术,探讨共济失调患者在主动与被动复杂对指运动模式下关键脑功能区激活体积和强度的变化.方法 选取共济失调患者16例作为病例组,另选10名健康志愿者作为正常组.入选者均进行主动与被动复杂对指运动,在这两种运动模式下进行BOLD-fMRl检查,记录相应脑运动功能区的激活体积和强度并进行定量分析.采用共济失调量表(ICARS)对共济失调患者的共济运动进行评分.结果 病例组患手主动运动时,同侧辅助运动区(SMA)激活体积大于正常组同侧手的测定结果,激活强度也高于正常组;同侧小脑的激活体积和激活强度则小于正常组,小脑激活区的出现率也低于正常组.病例组患手主动运动时,同侧小脑激活区的体积、激活强度与共济失调量表评分无相关性.结论 共济失调患者患侧小脑功能下降,而同侧SMA可以发挥代偿作用,临床共济失调量表的评分尚不能准确反映小脑功能情况.     

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.     

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     

正常人手指简单运动时脑功能区被激活的SPECT脑血流研究

目的运用单光子发射断层扫描仪(SPECT)对比观察不同年龄组正常人执行手指简单运动时脑内不同感兴趣区(ROI)的血流量变化,以期探讨运动功能区的作用。方法健康的志愿者18例,按照年龄划分为青年组和中老年组。每一受试对象分别安静和执行手指简单运动状态下进行99mTcECDSPECT扫描脑血流量测定。结果两组间的运动频率无明显差异,但中老年组的错误率显著高于青年组。运动激活后各脑叶的局部血流量无明显变化,而对侧初级运动区(M1)、同侧小脑、双侧辅助运动区(SMA)血流量显著变化。两组间相比,中老年组的对侧M1、同侧小脑的血流量增加低于年轻组,而双侧SMA则大于青年组(P<0.05)。结论手指的简单运动主要激活对侧M1、同侧小脑、双侧SMA;中老年组的SMA激活比青年组明显,显示中、老年人通过自身代偿机制调动更多的SMA参与运动的启动与执行。     

健康成年人手部主动及被动运动时大脑功能区的功能性磁共振成像研究

目的 利用血氧水平依赖性功能性磁共振成像技术探讨健康成年人手部主动、被动对掌运动时的脑激活区的特点,为运动疗法治疗脑卒中提供理论依据.方法 9名健康成年人参加实验.以右手主动及被动对掌运动作为刺激模式,采用区块设计,利用SPM5软件进行数据处理.测量位于对侧感觉运动区及运动前区的脑激活区的中点,并统计各脑区出现激活的频数.结果 主动及被动手对掌运动时主要激活的脑区包括:对侧感觉运动皮质(SMC)区、对侧运动前皮质(PMC)区、双侧辅助运动区(SMA)及同侧小脑,其中对侧SMC区的激活频率最高;被动运动时所激活的对侧SMC和PMC区的几何中心较主动运动时偏后.结论 主动和被动对掌运动均可引起运动相关脑区激活,两种运动模式所激活脑区在分布上无明显差别,但被动运动所激活的对侧SMC和PMC区几何中心较主动运动偏后.

Abstract：

Objective To assess differences in brain activation between active and passive movement of the right hand using blood oxygen level-dependent functional magnetic resonance imaging (BOLD-fMRI). Methods Nine healthy adult right handed volunteers were studied. fMRI was performed with active and passive finger-to-finger movement. Results Right hand active and passive movement produced significant activation in the contralateral sensorimotor cortex ( SMC ), the contralateral premotor cortex ( PMC ), bilaterally in the supplementary motor area (SMA) and in the ipsilateral cerebellum. The activated brain areas were centered on the contralateral SMC and PMC and located more forward during active movement than during passive movement. The contralateral SMC was the most strongly and the most frequently activated brain area. The contralateral posterior parietal cortex (PPC) was less relevant to the hand movements. Unlike active movement, passivemovement activated more areas in the posterior central gyrus than in the anterior central gyrus. Conclusions Both active and passive movement significantly activate the brain areas which are responsible for hand movement, but there are some differences in the locations of the cortex areas activated and in the incidence activation except in the contralateral SMC.     

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。     

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.     

Bimanual versus unimanual coordination: what makes the difference?

Using fMRI, we investigated the neuronal structures controlling bimanual coordination applying a visuomotor coordination task. Recent studies suggest the existence of a widespread network for the neuronal control of bimanual coordination including primary sensorimotor cortices (M1/S1), lateral and medial premotor cortices (PMC, SMA), cingulate motor area (CMA), and cerebellum (CB). In the present study, subjects performed bimanual and unimanual tasks requiring the coordination of two fingers at a time to navigate a cursor on a computer screen. Thus, in contrast to previous studies, we are using appropriate unimanual control (UNI) tasks. By using this new motor task, we identified a similar activation network for uni- and bimanual movements. Subjects exhibited bilateral activations in PMC, SMA, posterior-parietal cortex (PPC), occipital, and inferiotemporal cortex, as well as in the contralateral M1/S1 and ipsilateral CB. We did not find any additional activation when comparing bimanual with unimanual conditions. The lack of significant activation in the comparison "bimanual > unimanual" gives reason to suggest that this network is not limited to the control of bimanual motor actions, but responsible for unimanually coordinated movements as well. Interestingly, we found stronger activations for unimanual as compared to bimanual coordination. We hypothesize that task difficulty (degrees of freedom to control, e.g., number of limbs) is more important in determining which network components are activated and to what extent, compared to the factor of bimanuality. It even seemed to be less demanding for the motor system to control the cursor bimanually compared to the unimanual performance with two adjacent fingers.     

A simultaneous EEG-fMRI study of painful electric stimulation

Together with a detailed behavioral analysis, simultaneous measurement of functional magnetic resonance imaging (fMRI) and electroencephalography (EEG) permits a better elucidation of cortical pain processing. We applied painful electrical stimulation to 6 healthy subjects and acquired fMRI simultaneously with an EEG measurement. The subjects rated various stimulus properties and the individual affective state. Stimulus-correlated BOLD effects were found in the primary and secondary somatosensory areas (SI and SII), the operculum, the insula, the supplementary motor area (SMA proper), the cerebellum, and posterior parts of the anterior cingulate gyrus (ACC). Perceived pain intensity was positively correlated with activation in these areas. Higher unpleasantness rating was associated with suppression of activity in areas known to be involved in stimulus categorization and representation (ventral premotor cortex, PCC, parietal operculum, insula) and enhanced activation in areas initiating, propagating, and executing motor reactions (ACC, SMA proper, cerebellum, primary motor cortex). Concordant dipole localizations in SI and ACC were modeled. Using the dipole strength in SI, the network was restricted to SI. The BOLD signal change in ACC was positively correlated to the individual dipole strength of the source in ACC thus revealing a close relationship of BOLD signal and possibly underlying neuronal electrical activity in SI and the ACC. The BOLD signal change decreased in SI over time. Dipole strength of the ACC source decreased over the experiment and increased during the stimulation block suggesting sensitization and habituation effects in these areas.     

Role of hyperactive cerebellum and motor cortex in Parkinson's disease

Previous neuroimaging studies have found hyperactivation in the cerebellum and motor cortex and hypoactivation in the basal ganglia in patients with Parkinson's disease (PD) but the relationship between the two has not been established. This study examined whether cerebellar and motor cortex hyperactivation is a compensatory mechanism for hypoactivation in the basal ganglia or is a pathophysiological response that is related to the signs of the disease. Using a BOLD contrast fMRI paradigm PD patients and healthy controls performed automatic and cognitively controlled thumb pressing movements. Regions of interest analysis quantified the BOLD activation in motor areas, and correlations between the hyperactive and hypoactive regions were performed, along with correlations between the severity of upper limb rigidity and BOLD activation. There were three main findings. First, the putamen, supplementary motor area (SMA) and pre-SMA were hypoactive in PD patients. The left and right cerebellum and the contralateral motor cortex were hyperactive in PD patients. Second, PD patients had a significant negative correlation between the BOLD activation in the ipsilateral cerebellum and the contralateral putamen. The correlation between the putamen and motor cortex was not significant. Third, the BOLD activation in the motor cortex was positively correlated with the severity of upper limb rigidity, but the BOLD activation in the cerebellum was not correlated with rigidity. Further, the activation in the motor cortex was not correlated with upper extremity bradykinesia. These findings provide new evidence supporting the hypothesis that hyperactivation in the ipsilateral cerebellum is a compensatory mechanism for the defective basal ganglia. Our findings also provide the first evidence from neuroimaging that hyperactivation in the contralateral primary motor cortex is not a compensatory response but is directly related to upper limb rigidity.     

Effective connectivity of brain networks during self-initiated movement in Parkinson's disease

Patients with Parkinson's disease (PD) have difficulty in performing self-initiated movements. The neural mechanism of this deficiency remains unclear. In the current study, we used functional MRI (fMRI) and psychophysiological interaction (PPI) methods to investigate the changes in effective connectivity of the brain networks during performance of self-initiated movement in PD patients. Effective connectivity is defined as the influence one neuronal system exerts over another. fMRIs were acquired in 18 PD patients and in 18 age- and sex-matched healthy controls, when performing a self-initiated right hand tapping task. We chose the left primary motor cortex (M1), rostral supplementary motor area (pre-SMA), left premotor cortex (PMC), left putamen, and right cerebellum as index areas for PPI analysis. During the performance of self-initiated movement, connectivity between the putamen and M1, PMC, SMA, and cerebellum was decreased in PD patients compared to controls. In contrast, connections between the M1, pre-SMA, PMC, parietal cortex, and cerebellum were increased in PD patients compared to controls. In addition, the M1, pre-SMA, PMC, and cerebellum also had less connectivity with the dorsal lateral prefrontal cortex in PD. In PD patients, the effective connectivity between the putamen and M1, PMC, SMA, and cerebellum negatively correlated with the Unified Parkinson's Disease Rating Scale (UPDRS) motor scores; whereas the connectivity between the M1, pre-SMA, PMC, and cerebellum positively correlated with the UPDRS motor scores. Our findings demonstrate that the pattern of interactions of brain networks is disrupted in PD during performance of self-initiated movements. The striatum-cortical and striatum-cerebellar connections are weakened. In contrast, the connections between cortico-cerebellar motor regions are strengthened and may compensate for basal ganglia dysfunction. These altered interregional connections are more deviant when the disorder is more severe, and, therefore, our results give further insight into the explanation for the difficulty in performing self-initiated movements in PD.     

Brain areas involved in interlimb coordination: a distributed network.

Whereas behavioral studies have made significant contributions toward the identification of the principles governing the coordination of limb movements, little is known about the role of higher brain areas that are involved in interlimb coordination. Functional magnetic resonance imaging (fMRI) was used to reveal the brain areas activated during the cyclical coordination of ipsilateral wrist and foot movements. Six normal subjects performed five different tasks that were presented in a random order, i.e., isolated flexion-extension movements of the right wrist (WRIST) and right foot (FOOT), cyclical coordination of wrist and foot according to the isodirectional (ISODIR) and nonisodirectional (NON-ISODIR) mode, and rest (REST). All movements were auditory paced at 66 beats/min. During the coordination of both limb segments, a distributed network was identified showing activation levels in the supplementary motor area (SMA), cingulate motor cortex (CMC), premotor cortex (PMC), primary sensorimotor cortex (M1/S1), and cerebellum that exceeded the sum of the activations observed during the isolated limb movements. In addition, coordination of the limb movements in different directions was associated with extra activation of the SMA as compared to movements in the same direction. It is therefore concluded that the SMA is substantially involved in the coordination of the nonhomologous limbs as part of a distributed motor network. Accordingly, the long-standing exclusive association that has been made between this medial frontal area and bimanual (homologous) coordination needs to be abandoned and extended towards other forms of interlimb coordination (nonhomologous).     

针刺对脑梗死后痉挛期患者脑功能重塑作用的功能磁共振成像研究

目的:观察健康人及脑梗死后左侧偏瘫患者执行左侧上肢运动及针刺左侧阳陵泉穴后的激活区分布特点,初步探讨脑梗死后痉挛期脑功能重塑的特点及针刺阳陵泉对其影响的机制。方法:观察8例健康人及5例脑梗死后左侧偏瘫患者。试验1:分别对正常组及偏瘫组进行左侧上肢运动。试验2:分别对正常组及偏瘫组针刺左侧阳陵泉穴。两个试验均采用组块设计模式,运用BOLD-f MRI技术及Brain Voyager软件分析方法显示激活情况。结果:正常组执行运动任务出现右侧初级感觉运动皮质及双侧小脑的明显激活;正常组针刺左侧阳陵泉穴出现左侧小脑、两侧中央后回和顶下小叶的激活;偏瘫组执行运动任务,双侧大脑皮质均有明显激活,包括双侧初级感觉运动皮质(SM1)、运动前区(PMC)和次级运动区(PPC)、双侧丘脑、小脑蚓部、双侧小脑、右侧岛叶、壳核,以及健侧苍白球;偏瘫组针刺左侧阳陵泉穴出现中脑、左侧大脑皮质的运动前区和次级运动区的激活。结论:脑梗死后痉挛期脑功能重塑的机制在于通过功能区的转移和次级功能区的功能代偿,而针刺阳陵泉穴主要作用于锥体外系,通过调节中枢神经递质的释放,缓解痉挛状态。     

Force related activations in rhythmic sequence production

Brain imaging studies have implicated the basal ganglia in the scaling of movement velocity. Basal ganglia activation has also been reported for movement timing. We investigated the neural correlates of scaling of force and time in the production of rhythmic motor sequences using functional magnetic resonance imaging (fMRI) of the human brain. Participants (N = 13) were imaged while squeezing a rigid force transducer in a near isometric manner between thumb and index finger, to reproduce four different rhythmic sequences. The responses were separated by either equal (600 ms) or alternating (400, 800 ms) intervals, and produced with either equal (12 N) or alternating (8, 16 N) forces pulses. Intervals and force levels were balanced across each condition. The primary motor cortex (M1), supplementary motor area (SMA), basal ganglia, thalamus, and cerebellum were activated during the production of sequences marked by equal interval and force. There was no reliable main effect of alternating interval. In contrast, greater activation of these regions was associated with the extra demands of responding with alternating force pulses. We interpret the data as identifying a significant role of the BG in the control of force. In addition, the results indicate the importance of monitoring force when studying brain activation associated with motor timing.     

CASL fMRI of subcortico-cortical perfusion changes during memory-guided finger sequences

Arterial spin labeling (ASL) perfusion functional magnetic resonance imaging (fMRI) is an attractive alternative to BOLD fMRI. Nevertheless, current ASL fMRI techniques are limited by several factors that hamper more routine applications in humans. One of these factors is restricted brain coverage so that whole-brain ASL fMRI studies have never been reported. The present study tested the ability of a multislice continuous ASL (CASL) fMRI approach using a small surface coil placed on the subject's neck to map changes in regional cerebral blood flow (rCBF) throughout the brain while healthy individuals (N = 15) performed memory-guided sequential finger movements at a mean rate of approximately 0.5 Hz. As predicted by results from a large number of studies, reliable task-related increases in flow were detected across subjects not only in primary and associative cortical areas but also in subcortical brain regions. When normalized to baseline, rCBF increased 31% in the hand representation area (HRA) of left primary motor cortex (M1), 13% in the left supplementary motor area proper (SMA), 10% in the left dorsolateral prefrontal cortex (DLPFC), 10-18% in the bilateral intraparietal sulci, 6% in the HRA of left putamen, 10% in the left thalamus, and 17% in the right anterior cerebellum. In addition to these increases, 6% and 4% decreases in rCBF were detected in the HRA of the right M1 and the bilateral posterior cingulate sulci, respectively. These results demonstrate that perfusion-based fMRI using CASL with a separate labeling coil can now be used to characterize task-related flow changes in most of the brain volume with adequate accuracy and sensitivity.