卒中早期手指被动运动的脑功能磁共振成像研究

目的应用扩散张量成像及BOLD-fMRI技术观察卒中早期手指被动运动时大脑半球相关区域血氧水平的变化情况.方法采用1.5 T MR成像系统对6名早期卒中患者进行BOLD-fMRI及扩散张量成像,采用手指被动屈伸运动作为fMRI的刺激任务.结果在锥体束中断时,卒中早期健手运动时激活双侧SMC区,患手运动可激活对侧半球后顶叶皮层及同侧SMC区;锥体束较完整时健手运动时激活对侧SMC区,患手运动激活双侧SMC区、双侧后顶叶皮层.结论卒中早期可能发生运动功能通路的重构,但锥体束不同损伤情况下运动功能恢复可能存在不同的机制.DTI与fMRI联合应用将是监测和研究脑卒中后恢复的有用工具.     

Functional cortical changes in patients with multiple sclerosis and nonspecific findings on conventional magnetic resonance imaging scans of the brain

Recent functional magnetic resonance imaging (fMRI) work has suggested that cortical reorganisation might have an adaptive role in limiting the clinical impact of multiple sclerosis (MS) structural damage. In this study, we investigated whether, in patients with MS, the presence and extent of structural damage of the normal-appearing brain tissue are associated with the extent of the movement-associated pattern of cortical activations. Using fMRI and a general search method, we assessed the patterns of brain activations associated with simple motor tasks in 12 right-handed patients with clinically definite MS and nonspecific T2-weighted abnormalities on conventional MRI scans of the brain and compared them with those from 12 sex- and age-matched right- handed healthy controls. Also investigated were the extent to which the fMRI changes correlated with normal-appearing white matter and grey matter (GM) pathology, measured using diffusion tensor MRI. When performing the simple motor task with the dominant hand, MS patients had more significant activations of the ipsilateral supplementary motor area (SMA), the ipsilateral superior frontal sulcus, the contralateral superior temporal gyrus, and the thalamus than controls. On the contrary, healthy subjects showed more significant activations of the medial part of the contralateral parieto-occipital fissure and the ipsilateral primary sensorimotor cortex (SMC) than patients with MS. In patients with MS, the relative activation of the ipsilateral SMA was correlated with the peak height (r = -0.88, P < 0.001) and position (r = 0.87, P < 0.001) of the GM mean diffusivity histogram. This study shows that cortical reorganisation occurs over a rather distributed sensorimotor network even in patients with MS and nonspecific abnormalities on conventional brain MRI scans. This suggests that, in patients with MS, an increased recruitment of movement-associated cortical network can be elicited by the presence of normal-appearing tissue pathology, which is independent of macroscopic T2-weighted abnormalities.     

Evidence for axonal pathology and adaptive cortical reorganization in patients at presentation with clinically isolated syndromes suggestive of multiple sclerosis

Previous work has suggested that functional reorganization of cortical areas might have a role in limiting the clinical impact of axonal pathology in patients with established multiple sclerosis (MS). Since there is evidence for irreversible tissue damage even in patients with early MS, we assessed, using functional MRI (fMRI) and a general search method, the brain pattern of movement-associated cortical activations in patients at presentation with clinically isolated syndromes (CIS) suggestive of MS. To elucidate the role of cortical reorganization in these patients, we also investigated the extent to which the fMRI changes correlated with the extent of overall axonal injury of the brain. From 16 right-handed patients at presentation with CIS and 15 right-handed, age- and sex-matched healthy volunteers, we obtained: (1). fMRI (repetitive flexion-extension of the last four fingers of the right hand), (2). conventional MRI scans, and (3). a new, unlocalized proton MR spectroscopy ((1)HMRS) sequence to measure the concentration of N-acetylaspartate of the whole brain (WBNAA). Compared to controls, patients with CIS had more significant activations of the contralateral primary somatomotor cortex (SMC), secondary somatosensory cortex, and inferior frontal gyrus. They also had significant decreased WBNAA concentration. Relative activation of the contralateral primary SMC was strongly correlated with WBNAA levels (r = -0.78, P < 0.001). This study shows that axonal pathology and functional cortical changes over a rather distributed sensorimotor network occur in patients at presentation with CIS suggestive of MS and that these two aspects of the disease are strictly correlated. This suggests that the increased functional recruitment of the cortex in these patients might have an adaptive role in limiting the clinical impact of irreversible tissue damage.     

The level of spinal cord involvement influences the pattern of movement-associated cortical recruitment in patients with isolated myelitis

Using fMRI, an increased recruitment of the ipsilateral primary sensorimotor cortex (SMC), supplementary motor area, and middle frontal gyrus has been detected in patients with cervical cord myelitis of possible demyelinating origin. The aim of this study was to evaluate, using fMRI, whether the level of cord involvement influences cortical reorganization by comparing patients with isolated myelitis of the cervical and the dorsal portions of the cord, and to investigate whether the extent of cortical reorganization is associated with the extent of cervical cord pathology measured using magnetization transfer (MT) MRI. We studied 24 right-handed patients (14 with a previous involvement of the cervical cord and 10 with an involvement of the dorsal cord) in a chronic and clinically stable phase following an isolated myelitis of possible demyelinating origin and 15 sex- and age-matched healthy controls. During a single session, we obtained fMRI during repetitive flexion-extension of the last four fingers of the right and left hands and cervical cord MT MRI. Average cord MTR was lower in patients with cervical (P < 0.0001) and dorsal (P = 0.0001) myelitis than in controls. Compared to controls and for both tasks, patients with myelitis had an increased recruitment of the ipsilateral primary SMC, which was independent of the level of cord involvement. On the contrary, patients with cervical myelitis had a more widespread recruitment of frontal and parietal regions, whereas those with dorsal myelitis had a more widespread recruitment of temporal and cerebellar regions. Strong correlations (r values ranging from -0.72 to -0.88) were found between relative activations of cortical areas and the severity of cervical cord damage. Patients with isolated myelitis have different patterns of movement-associated cortical activations according to the level of cord involvement. This "level-dependent" functional reorganization of the cortex is likely to have an adaptive role in limiting the clinical outcome of cord damage and should be considered when designing rehabilitation strategies for these patients.     

An fMRI study of the motor system in patients with neuropsychiatric systemic lupus erythematosus

Functional cortical changes have been demonstrated in patients with several neurological conditions, including stroke, tumors and MS. The correlation found between the extent of fMRI activations and the extent and severity of brain structural damage suggests an adaptive role of these functional changes. In this study, we assess, using fMRI, the brain pattern of movement-associated cortical activations in neuropsychiatric systemic lupus erythematosus (NPSLE) patients and investigate whether the extent of cortical reorganization is associated with the extent of brain pathology, measured on dual-echo and diffusion tensor (DT) MR images. From 14 right-handed NPSLE patients and 14 matched controls, we obtained: (a) fMRI during the performance of repetitive flexion-extension of the last four fingers of the right hand; (b) dual-echo and (c) pulsed-gradient spin-echo echo-planar sequence to calculate DT MRI maps of the normal-appearing white (NAWM) and gray (NAGM) matter. Brain T2-visible abnormalities were detected in 11 NPSLE patients. Compared with controls, NPSLE patients had significantly higher NAWM fractional anisotropy histogram peak height (P = 0.005), and more significant activations of the contralateral primary sensorimotor cortex, putamen and dentate nucleus. They also had more significant activations of several regions located in the frontal and parietal lobes as well as of MT/V5 and the middle occipital gyrus, bilaterally. Strong correlations (r values ranging from 0.79 to 0.87) were found between relative activations of sensorimotor areas and the extent and severity of brain damage. Movement-associated functional cortical changes do occur in patients with NPSLE and might contribute to the maintenance of their normal functional capacities.     

A functional MRI study of movement-associated cortical changes in patients with Devic's neuromyelitis optica

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.     

A functional magnetic resonance imaging study of patients with secondary progressive multiple sclerosis

Although several functional magnetic resonance imaging (fMRI) studies have shown adaptive cortical changes in patients with early multiple sclerosis (MS), the presence of brain plasticity and its role in limiting the functional consequences of brain tissue damage in patients with secondary progressive (SP) MS have not been fully investigated yet. In this study, we assessed the movement-associated brain pattern of cortical activations in patients with SPMS and investigated whether the extent of cortical brain activations is correlated with the extent of brain structural changes. From 13 right-handed SPMS patients and 15 sex- and age-matched healthy volunteers, we obtained: (a) brain dual-echo scans; (b) brain mean diffusivity and fractional anisotropy maps of the normal-appearing white (NAWM) and gray matter (NAGM); (c) fMRI during the performance of simple motor tasks [flexion-extension of the last four fingers of the right hand (task 1) and flexion-extension of the right foot (task 2)]. Compared to healthy volunteers, during task 1 performance, SPMS patients showed more significant activations of the ipsilateral inferior frontal gyrus, middle frontal gyrus, bilaterally, and contralateral intraparietal sulcus. During task 2 performance, SPMS patients had more significant activations of the contralateral primary sensorimotor cortex and thalamus and of the ipsilateral upper bank of sylvian fessure. For both tasks, strong correlations (r values ranging from -0.83 to 0.88) were found between relative activations of cortical areas of the motor network and the severity of structural changes of the NAWM and NAGM. This study demonstrates that cortical plasticity does occur in patients with SPMS and that it might have a role in limiting the clinical impact of MS-related damage. It also suggests that, in these patients, functional abilities are sustained by increased recruitment of highly specialized cortical areas.     

Functional magnetic resonance imaging correlates of fatigue in multiple sclerosis

Although fatigue is a common and troublesome symptom of multiple sclerosis (MS), its pathogenesis is poorly understood. In this study, we used functional magnetic resonance imaging (fMRI) to test whether a different pattern of movement-associated cortical and subcortical activations might contribute to the development of fatigue in patients with MS. We obtained fMRI during the execution of a simple motor task with completely normally functioning hands from 15 MS patients with fatigue (F), 14 MS patients without fatigue (NF), and 15 sex- and age-matched healthy volunteers. F and NF MS patients were also matched for major clinical and MRI variables. FMRI data were analyzed using statistical parametric mapping. In all patients, severity of fatigue was rated using the Fatigue Severity Scale (FSS). Compared to healthy subjects, MS patients showed more significant activations of the contralateral primary somatomotor cortex, the contralateral ascending limb of the Sylvian fissure, the contralateral intraparietal sulcus (IPS), the contralateral supplementary motor area, and the ipsilateral and contralateral cingulate motor area (CMA). Compared to F MS patients, NF patients showed more significant activations of the ipsilateral cerebellar hemisphere, the ipsilateral rolandic operculum, the ipsilateral precuneus, the contralateral thalamus, and the contralateral middle frontal gyrus. In contrast, F MS patients had a more significant activation of the contralateral CMA. Significant inverse correlations were found between FSS scores and relative activations of the contralateral IPS (r = -0.63), ipsilateral rolandic operculum (r = -0.61), and thalamus (r = -0.62). This study provides additional evidence that fatigue in MS is related to impaired interactions between functionally related cortical and subcortical areas. It also suggests that fMRI might be a valuable tool to monitor the efficacy of treatment aimed at reducing MS-related fatigue.     

计算机辅助上肢训练对脑卒中患者与正常人脑可塑性影响的功能磁共振成像对比研究

摘要 目的：探讨计算机辅助训练上肢对脑卒中患者与正常人脑可塑性的可能作用。 方法：对5名正常志愿者（对照组）及5例脑卒中上肢偏瘫患者（实验组）进行6周的计算机辅助训练,每周训练5次,在训练前、训练后分别在受试者屈伸左右腕关节时进行功能磁共振成像（fMRI）扫描,并对实验组进行Fulg-Meyer上肢功能评定（FMA）,改良Barthel指数（MBI）量表评定。 结果：实验组与对照组相比,治疗前,运动左侧腕关节时,激活脑区主要在左额中央前回（同侧的感觉运动皮质区）;治疗后,运动左侧腕关节时,实验组与对照组相比,激活脑区在同侧感觉运动皮质区,但激活强度及体素均较治疗前有明显的降低。治疗前,运动右腕关节时,两者的激活脑区的部位相似,均在对侧的SMC区及同侧的小脑,但激活强度和体素较对照组小;治疗后,运动右腕关节时,两组之间无显著差异。 结论：计算机辅助训练可诱导出大脑皮质功能区的重组与代偿,使其趋向正常化。     

Two different reorganization patterns after rehabilitative therapy: an exploratory study with fMRI and TMS

We used two complementary methods to investigate cortical reorganization in chronic stroke patients during treatment with a defined motor rehabilitation program. BOLD ("blood oxygenation level dependent") sensitive functional magnetic resonance imaging (fMRI) and intracortical inhibition (ICI) and facilitation (ICF) measured with transcranial magnetic stimulation (TMS) via paired pulse stimulation were used to investigate cortical reorganization before and after "constraint-induced movement therapy" (CI). The motor hand function improved in all subjects after CI. BOLD signal intensity changes within affected primary sensorimotor cortex (SMC) before and after CI showed a close correlation with ICI (r = 0.93) and ICF (r = 0.76) difference before and after therapy. Difference in number of voxels and ICI difference before and after CI also showed a close correlation (r = 0.92) in the affected SMC over the time period of training. A single subject analysis revealed that patients with intact hand area of M1 ("the hand knob") and its descending motor fibers (these patients revealed normal motor evoked potentials [MEP] from the affected hand) showed decreasing ipsilesional SMC activation which was paralleled by an increase in intracortical excitability. This pattern putatively reflects increasing synaptic efficiency. When M1 or its descending pyramidal tract was lesioned (MEP from the affected hand was pathologic) ipsilesional SMC activation increased, accompanied by decreased intracortical excitability. We suggest that an increase in synaptic efficiency is not possible here, which leads to reorganization with extension, shift and recruitment of additional cortical areas of the sensorimotor network. The inverse dynamic process between both complementary methods (activation in fMRI and intracortical excitability determined by TMS) over the time period of CI illustrates the value of combining methods for understanding brain reorganization.     

功能性核磁共振成像在计算机辅助的上肢功能训练治疗脑梗死上肢偏瘫中的应用研究

目的:探讨计算机辅助训练上肢对脑可塑性的可能作用。方法:脑卒中上肢偏瘫患者10例,均进行计算机辅助训练,治疗前后采用偏瘫上肢功能测试-香港版(FTHUE-HK),Fulg-Meyer上肢评定(FMA)及改良Barthel指数量表(MBI)评定上肢运动功能,及患者屈伸腕关节时进行功能核磁共振扫描(fMRI)。结果:治疗6周后,10例患侧的上肢功能评定FTHUE-HK、FMA及MBI评分均较治疗前后患侧上肢功能评定变化明显提高(P0.05)。fMRI扫描示:患者健侧手运动脑功能激活区主要位于对侧初级运动皮质区(SMC)及同侧小脑,患者健手在康复训练后脑激活区增多,包括对侧SMC区及同侧小脑、部分边缘系统;患者治疗前患侧手运动激活区分布广泛,而对侧SMC激活减少,同侧SMC激活增多,另主要还见辅助运动区激活增多;治疗后可见双侧SMC及辅助运动区激活,对侧SMC激活较治疗前增多,另主要还见对侧顶上小叶激活增多。结论:计算机训练可以有效改善脑卒中患者上肢运动功能,诱发大脑皮质功能重塑是其机制的重要组成部分。     

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。     

Multi-task functional MRI in multiple sclerosis patients without clinical disability

While the majority of individuals with multiple sclerosis (MS) develop significant clinical disability, a subset experiences a disease course with minimal impairment even in the presence of significant apparent tissue damage on magnetic resonance imaging (MRI). Functional magnetic resonance imaging (fMRI) in MS patients with low disability suggests that increased use of the cognitive control system may limit the clinical manifestation of the disease. The current fMRI studies tested the hypothesis that nondisabled MS patients show increased recruitment of cognitive control regions while performing sensory, motor and cognitive tasks. Twenty two patients with relapsing-remitting MS and an Expanded Disability Status Scale (EDSS) score of ≤ 1.5 and 23 matched healthy controls were recruited. Subjects underwent fMRI while observing flashing checkerboards, performing right or left hand movements, or executing the 2-back working memory task. Compared to control subjects, patients demonstrated increased activation of the right dorsolateral prefrontal cortex and anterior cingulate cortex during the performance of the working memory task. This pattern of functional recruitment also was observed during the performance of non-dominant hand movements. These results support the mounting evidence of increased functional recruitment of cognitive control regions in the working memory system of MS patients with low disability and provide new evidence for the role of increased cognitive control recruitment in the motor system.     

A functional MRI study of cortical activations associated with object manipulation in patients with MS

Previous functional magnetic resonance imaging (fMRI) studies of simple motor tasks have shown that in patients with multiple sclerosis (MS), there is an increased recruitment of several regions part of a complex sensorimotor network. These studies have suggested that this might be the case because patients tend to activate, when performing a simple motor task, regions that are usually activated in healthy subjects during the performance of more complex tasks due to the presence of subcortical structural damage. In this study, we tested this hypothesis by comparing the patterns of cortical activations during the performance of two tasks with different levels of complexity from 16 MS patients and 16 age- and sex-matched controls. The first task (simple) consisted of flexion-extension of the last four fingers of the right hand, and the second task (complex) consisted of object manipulation. During the simple task, MS patients had, when compared to controls, more significant activations of the supplementary motor area (SMA), secondary sensorimotor area, posterior lobe of the cerebellum, superior parietal gyrus (SPG), and inferior frontal gyrus (IFG). These three latter regions are part of a fronto-parietal circuit, whose activation occurs typically in the contralateral hemisphere of healthy subjects during object manipulation, as shown also by the present study. During the performance of the complex task, MS patients showed an increased bilateral recruitment of several areas of the fronto-parietal circuit associated with object manipulation, as well of several other areas, which were mainly in the frontal lobes. This study confirms that some of the regions that are activated by MS patients during the performance of simple motor tasks are part of more complex pathways, recruited by healthy subjects when more complex and difficult tasks have to be performed.     

动态功能性磁共振成像在强制性使用运动疗法治疗脑卒中上肢偏瘫中的应用研究

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。     

运动想象训练促进脑卒中患者上肢运动功能恢复的功能磁共振研究

摘要 目的：利用功能磁共振（fMRI）研究脑卒中患者运动想象训练后上肢功能重组潜在的脑重塑机制,为临床脑卒中患者的康复治疗提供一定的理论基础。 方法：选择9例脑卒中偏瘫患者,进行运动想象训练每周5次,每次约30min,共4周,并进行常规康复训练。应用Fugl-Meyer上肢运动功能量表（FMA-UL）分别在治疗前和治疗后4周评估患者的上肢运动功能。在4周康复干预前后对患者进行患手被动握拳任务下的fMRI检查,采用组块设计,利用SPM8软件进行数据处理,采用感兴趣区（ROI）的个体化分析,统计各ROI区的脑皮质激活情况,比较干预前后对侧感觉运动区（cSMC）的激活变化,分析脑卒中患者的脑重塑模式。 结果：4周运动想象干预后脑卒中患者的FM-UL评分从（22.44±11.59）分提高到（39.78±14.03）分（P=0.011）。比较干预前后两次fMRI检查脑皮质SMC区的激活情况,发现9例脑卒中患者的功能恢复呈现出两种不同的皮质重塑模式：一种模式为募集激活,即大部分患者第二次fMRI检查,患手被动任务下cSMC的激活增加（有6例患者）;另一种模式是集中激活,即小部分患者第二次fMRI检查,患手被动任务下cSMC的激活虽然是减少的,但其偏侧指数（LI-SMC）却是显著增加的（有3例患者）。 结论：运动想象训练可改善脑卒中患者的上肢运动功能,经过4周干预后脑卒中患者存在损伤同侧SMC区的募集激活和集中激活两种脑重塑模式,随着患者上肢功能的恢复,脑重塑机制逐渐倾向于损伤侧SMC的激活。     

Combined functional magnetic resonance imaging and transcranial magnetic stimulation evidence of ipsilateral motor pathway with congenital brain disorder: A case report

We present the case of 28-year-old man with schizencephaly who had mild left hemiparesis with mirror movement. Brain mapping using functional magnetic resonance imaging (fMRI) and transcranial magnetic stimulation (TMS) for both hand muscles was done to evaluate his neurologic state. Motor evoked potential (MEP) from both abductor pollicis brevis (APB) muscles was obtained simultaneously. fMRI showed that the left primary sensorimotor cortex became active when the right fingers performed the flexion-extension exercise. The left primary sensorimotor cortex, left prefrontal area, and both supplementary motor areas were activated with flexion-extension exercise of the left hand. Brain mapping for both APB muscles using TMS showed that no MEP was evoked in the right hemisphere, but a APB total of 5 sites were evoked in the left hemisphere simultaneously. The optimal scalp site for both APB muscles was present at the same site. The MEPs of both muscles which were evoked by stimulation of the optimal scalp site, showed similar latencies, amplitudes, and figures of potential. The similarities in both MEPs and the same optimal scalp site support the assumption that MEPs of both APB muscles are produced by the corticospinal tract originating from the same motor cortex. Our results showed that the ipsilateral motor pathway extended from the unaffected left hemisphere to both hand muscles. This finding may reflect functional reorganization of motor area in a patient with congenital brain disorder.     

单侧皮层下缺血性脑卒中患者运动功能磁共振成像的纵向研究

目的分析单侧皮层下缺血性脑卒中患者患侧肢体运动时脑部激活区随时间的动态变化过程,以及与运动功能康复水平的关系。方法对6名健康志愿者与3例单侧皮层下缺血性脑卒中患者进行血氧水平依赖功能磁共振成像（BOLD-fMRI）,分别采取单侧手指和患侧手指顺序对指运动任务。采用统计参数图进行数据分析和脑功能区定位,计算不同感兴趣区内激活体素数目,并计算偏侧化指数（LI）。扫描结束后记录患者上肢Fugl-Meyer运动评分。对患者在发病后8个月内分别行两侧BOLD-fMRI检查,比较两次激活区域及LI的变化。结果脑卒中患者激活区较健康人广泛,3例患者在发病早期激活范围存在差异,但均表现为双侧感觉运动区（SMC）激活;在发病晚期,肢体同侧SMC激活减少,对侧SMC激活增多,相应的半球、SMC、M1区LI增高。结论单侧皮层下脑梗死患者随着病程时间延长,功能区逐渐向对侧SMC局限化。     

Functional magnetic resonance image finding of cortical activation by neuromuscular electrical stimulation on wrist extensor muscles

OBJECTIVE: To investigate the effects that neuromuscular electrical stimulation on the wrist extensor muscles have on the cerebral cortex. DESIGN: A functional magnetic resonance imaging study was performed on eight normal volunteers. The activation task was the maximum wrist extension by neuromuscular electrical stimulation, applied through a two-channel electrical stimulator. Monophasic square-wave pulses were used. The activation maps were generated by the threshold test maps. The level of primary motor cortex and primary sensory cortex activations was estimated. RESULTS: Among the eight subjects, seven showed significant activation on contralateral primary sensorimotor cortex by neuromuscular electrical stimulation on the wrist extensor muscles. In these seven subjects, additional bilateral or contralateral supplementary motor area activations were also observed. The number of activated pixels on the primary sensory cortex was slightly greater than that on the primary motor cortex. CONCLUSION: Neuromuscular electrical stimulation, when applied to the peripheral muscles, seems to have a direct effect on the cerebral cortex.     

Brain activation of lower extremity movement in chronically impaired stroke survivors

Lower extremity paresis poses significant disability to chronic stroke survivors. Unlike for the upper extremity, cortical adaptations in networks controlling the paretic leg have not been characterized after stroke. Here, the hypotheses are that brain activation associated with unilateral knee movement in chronic stroke survivors is abnormal, depends on lesion location, and is related to walking ability. Functional magnetic resonance imaging of unilateral knee movement was obtained in 31 patients 26.9 months (mean, IQ range: 11.3-68.1) after stroke and in 10 age-matched healthy controls. Strokes were stratified according to lesion location. Locomotor disability (30 ft walking speed) did not differ between patient groups (9 cortical, 12 subcortical, 10 brainstem lesions). Significant differences in brain activation as measured by voxel counts in 10 regions of interest were found between controls and patients with brainstem (P = 0.006) and cortical strokes (P = 0.002), and between subcortical and cortical patients (P = 0.026). Statistical parametric mapping of data per group revealed similar activation patterns in subcortical patients and controls with recruitment of contralateral primary motor cortex (M1), supplementary motor area (SMA), and bilateral somatosensory area 2 (S2). Cortical recruitment was reduced in brainstem and cortical stroke. Better walking was associated with lesser contralateral sensorimotor cortex activation in brainstem, but stronger recruitment of ipsilateral sensorimotor and bilateral somatosensory cortices in subcortical and cortical patients, respectively. A post hoc comparison of brainstem patients with and without mirror movements (50%) revealed lesser recruitment of ipsilateral cerebellum in the latter. Subcortical patients with mirror movements (58%) showed lesser bilateral sensorimotor cortex activation. No cortical patient had mirror movements. The data reveal adaptations in networks controlling unilateral paretic knee movement in chronic stroke survivors. These adaptations depend on lesion location and seem to have functional relevance for locomotion.