Functional magnetic resonance imaging study of writer’s cramp

Background Writer＇s cramp is a type of task specific idiopathic focal dystonia and has an incompletely understood pathophysiology. The present study utilized functional magnetic resonance imaging （fMRI） to investigate what type of brain activity correlates with writer＇s cramp and its physiological mechanism.Methods Ten patients with writer＇s cramp were age and gender matched with ten nealthy control suojects in a block design. Subjectswere scanned by fMRI while performing three consecutive, visually instructive, tasks with MR Vision 2000： （1） suppositional writing, （2） writing with finger and （3） writing with a pencil. Data was analysed using AFNI software for groups of patients and controls.Results The patients with writer＇s cramp showed significant activations of contralateral basal ganglion （especially the putamen）, motor cortex （primary sensorimotor cortex, supplementary motor cortex, premotor cortex） and ipsilateral cerebellar hemisphere in writing with a pencil compared with controls; whereas there was no obvious difference between patients and controls during writing with finger. Furthermore, these differences exist in the stibtractive activated maps for ＂writing with a pencil＂ minus ＂writing with finger＂ of patients, when the activation of subcortical area and insula in controls disappeared.Conclusions Abnormal activations of contralateral basal ganglion, motor cortex and ipsilateral cerebellar hemisphere of the patients with writer＇s cramp suggest dysfunction of basal ganglion and subcortical-cortical loop might play a pathophysiological role in writer＇s cramp.     

Preoperative blood oxygen level-dependent functional magnetic resonance imaging in patients with gliomas involving the motor cortical areas

Background Blood oxygen level-dependent （BOLD） functional magnetic resonance imaging （fMRI） plays an important role in identifying functional cortical areas of the brain, especially in patients with gliomas. This study aimed to assess the value of fMRI in presurgical planning and functional outcome of patients with gliomas in the motor cortical areas. Methods Twenty-six patients with gliomas in the motor cortex were recruited in the study. Before operation, fMRI was performed in each patient to obtain the mapping of bilateral hands area on the primary sensorimotor cortex. This examination was performed on a 3.0T scanner with a bilateral hands movement paradigm. During microsurgery under awake anesthesia, the motor area was identified using direct electrical stimulation and compared with preoperative mapping. Finally the tumor was resected as much as possible with the motor cortex preserved in each patient. Karnofsky performance status （KPS） was evaluated in all patients before and after operation. Results Twenty-three patients showed a successful fMRI mapping. Among them, 19 were calssified to be grade Ⅲ; 4, grade Ⅱ; 3, grade Ⅰ. The operation time was about 7 hours in the 23 patients, 8.5 hours in the other 3. The pre-and postoperative KPS score was 82.3±8.6 and 94.2±8.1, respectively. Conclusions Preoperative fMRI of the hand motor area shows a high consistency with intraoperative cortical electronic stimulation. Combined use of the two methods shows a maximum benefit in surgical treatment.     

Laterality of brain areas associated with arithmetic calculations revealed by functional magnetic resonance imaging

Asymmetry of bilateral cerebral function, i.e. laterality, is an important phenomenon in many brain actions : arithmetic calculation may be one of these phenomena. In this study, first, laterality of brain areas associated with arithmetic calculations was revealed by functional magnetic resonance imaging (fMRI). Second, the relationship among laterality, handedness, and types of arithmetic task was assessed. Third, we postulate possible reasons for laterality. Methods Using a block-designed experiment, twenty-five right-handed and seven left-handed healthy volunteers carried out simple calculations, complex calculations and proximity judgments. T1 WI and GRE-EPI fMRI were performed with a GE 1.5T whole body MRI scanner. Statistical parametric mapping ( SPM99 ) was used to process data and localize functional areas. Numbers of activated voxels were recorded to calculate laterality index for evaluating the laterality of functional brain areas. Results For both groups, the activation of functional areas in the frontal lobe showed a tendency towards the nonpredominant hand side, but the functional areas in the inferior parietal lobule had left laterality. During simple and complex calculations, the laterality indices of the prefrontal cortex and premotor area were higher in the right-handed group than that in the left-handed group, whereas the laterality of the inferior parietal lobule had no such significant difference. In both groups, when the difficulty of the task increased, the laterality of the prefrontal cortex, premotor area, and inferior parietal lobule decreased, but the laterality of posterior part of the inferior frontal gyrus increased. Conclusions The laterality of the functional brain areas associated with arithmetic calculations can be detected with fMRI. The laterality of the functional areas was related to handedness and task difficulty.     

Cortical language activation in aphasia: a functional MRI study

Background Functional neuroimaging has been used in neurolinguistic research on normal subjects and on patients with brain damage. This study was designed to investigate the differences of the neural basis underlying language processing between normal subjects and aphasics. Methods Functional magnetic resonance imaging (fMRI) was used to map the language network in 6 normal subjects and 3 patients with aphasia who were in the stage of recovery from acute stroke. The participants performed a word generation task during multi-slice functional scanning for the measurement of signal change associated with regional neural activity induced by the task. Results In normal subjects, a distributed language network was activated. Activations were present in the frontal, temporal, parietal and occipital regions. In the patient group, however, no activation was detected in the left inferior frontal gyrus whether the patient had a lesion in the left frontal lobe or not. Two patients showed activations in some right hemisphere regions where no activation appeared in normal subjects. Conclusions fMRI with word generation task is feasible for evaluating language function in aphasic patients. Remote effect of focal lesion and functional redistribution or reorganisation can be found in aphasic patients.     

Cortical Thinning Pattern of Bulbar-and Spinal-onset Amyotrophic Lateral Sclerosis: a Surface-based Morphometry Study

Objective The precise cortical thinning pattern has not been elucidated for onset subtypes of amyotrophic lateral sclerosis (ALS). The current study aimed to investigate the altered cortical thickness signatures of the bulbar-onset and spinal-onset ALS using surface-based morphometry, and the correlation between the cortical thickness of positive brain regions and clinical variables of the patients. Methods MR structural images were obtained from 65 ALS patients (15 bulbar-onset, 50 spinal-onset) and 65 normal controls (NCs) on a 3.0T MRI system. The structural images were segmented into gray matter and white matter based on DARTEL method and the central cortical surfaces were reconstructed using projection-based thickness method. The surface-based morphometry was performed to identify the alteration of cortical thickness in overall ALS patients, bulbar-onset ALS patients and spinal-onset ALS patients comparing to the NCs. The correlation analysis was applied between the clinical variables and the mean cortical thickness of the abnormal brain regions with age and sex as covariates. Results The cortex thinning of ALS patients was located in the left precentral gyrus, left postcentral gyrus, right gyrus rectus and right medial precentral gyrus. The bulbar-onset ALS (ALS-bulbar) presented motor cortex thinning of left precentral gyrus and right supplementary motor cortex, and the spinal-onset ALS (ALS-spinal) suffered from extra-motor cortex thinning of left posterior insula and right gyrus rectus. In ALS patients, the thickness of right gyrus rectus was negatively correlated to disease duration (r=-0.311, P=0.013), the thickness of right precentral gyrus was positively correlated to the score of ALS functional rating score-revise (ALSFRS-R) (r=0.271, P=0.032). The thickness of motor cortices in ALS-bulbar were not correlated to disease duration and ALSFRS-R score; the thickness of extra-motor cortices in ALS-spinal were negatively correlated to the disease duration (left insula, r=-0.409, P=0.004; right gyrus rectus, r=-0.351, P=0.014). Conclusion The findings suggested that bilateral motor cortex thinning presented in bulbar-onset ALS and extra-motor cortex thinning presented in spinal-onset ALS. The motor cortex thinning may be the intrinsic pathophysiological change that associated to the disease disability, and extra-motor cortex thinning may be secondary pathophysiological change that associated to disease duration.     

Gray Matter Volume Changes over the Whole Brain in the Bulbar-and Spinal-onset Amyotrophic Lateral Sclerosis:a Voxel-based Morphometry Study

Objective To investigate cerebral structural signatures of the bulbar- and spinal-onset amyotrophic lateral sclerosis (ALS) using voxel-based morphometry on magnetic resonance imaging. Methods The MR structural images of the brain were obtained from 65 ALS patients (15 bulbar-onset, 50 spinal-onset) and 65 normal controls (NC) on a 3.0T MRI system. Gray matter (GM) volume changes were investigated by voxel-based morphometry, and the distribution of the brain regions with volume changes was compared between ALS and normal controls, as well as between bulbar-onset and spinal-onset ALS based on Neuromorphometrics atlas. Results On voxel-level the decreased volume of brain regions in ALS patients was located in the right precentral gyrus (rPrcGy) and right middle frontal gyrus compared with that in NC. The bulbar-onset ALS presented extra-motor cortex atrophy (fronto-temporal pattern), including left medial orbital gyrus, left inferior temporal gyrus and right middle temporal gyrus; the spinal-onset ALS suffered from motor cortex atrophy (rPrcGy dominance) and extra-motor cortex atrophy (fronto-temporal and extra-fronto-temporal pattern) compared with NC. The spinal-onset ALS featured by GM volume loss of left postcentral gyrus and bulbar-onset ALS featured by GM volume loss of left middle temporal gyrus compared with each other. Conclusions The asymmetric GM atrophy of the motor cortex and extra-motor cortex represents the common MRI structural signatures of spinal-onset ALS, and sole extra-motor cortex atrophy represents the structural signatures of bulbar-onset ALS. The present study also demonstrated that the pattern of GM damage is likely to distribute wider in spinal-onset ALS than in bulbar-onset ALS.     

Mapping cortical areas associated with Chinese word processing using functional magnetic resonance imaging

Objective To identify the cortical areas engaged during Chinese word processing using functional magnetic resonance imaging.(fMRI)and to examine the reliability and reproducibility of fMRI for localizaiton of functional areas in the human brain.Methods FMRI data were collected on 8 young,right-handed,native Chinese speakers during performance of Chinese synonym and homophone judgment tasks on two different clinical MRI systems(1.5T GE Signa Horizon and 1.5 T Siemens Vision).A Cross correlation analysis was used to statistically generate the activation map.Results Broca‘s area,Wernicke‘s area,bilateral extrastriate,and ventral temporal cortex were significantly activated during both the synonym and homophone activities.There was essentially no difference between results acquired on two different MRI systems.Conclusions FMRI can be used for localizing cortical areas critical to Chinese language processing in the human brain.The results are reliable and well reproducible across different clinical MRI systems.     

Fractionated resection on low grade gliomas involving Broca’s area and insights to brain plasticity

Background Resent advances on functional mapping have enabled us to conduct surgery on gliomas within the eloquent area. The objective of the article is to discuss the feasibility of a planned fractionated strategy of resection on low-grade gliomas （LGGs） involving Broca＇s area. We report the first surgical series of planned fractionated resections on LGGs within Broca＇s area, focusing on language functional reshaping.
Methods Four patients were treated with fractionated operations for LGGs involving Broca＇s area. All cases underwent conventional magnetic resonance （MR） scanning, language functional MR and diffusion tensor imaging （DTI） before operation. The resections were then performed on patients under awake anesthesia using intraoperative electrical stimulation （IES） for functional mapping. Pre- and post-operative neuro-psychological examinations were evaluated.
Results Total resections were achieved in all cases as confirmed by the postoperative control MR. After transient language worsening, all patients recovered to normal 3-6 months later. Language functional MR scannings have shown language functional cortical and subcortical pathway reorganization （in the perilesion or contra-lateral hemisphere） after the operation. All patients returned to a normal socioprofessional life.
Conclusions By utilizing the dynamic interaction between brain plasticity and fractionated resections, we can totally remove the tumor involving Broca＇s structure without inducing permanent postoperative deficits and even improve the quality of life.     

Preoperative 3T high field blood oxygen level dependent functional magnetic resonance imaging for glioma involving sensory cortical areas

Background Localization of sensory cortical areas during the operation is essential to preserve the sensory function. Intraoperative direct electrostimulation under awake anesthesia is the golden standard but time-consuming. We applied 3T high field blood oxygen level-dependent （BOLD） functional magnetic resonance imaging （fMRI） to identify the relationship between glioma and cortical sensory areas preoperatively and to guide intraoperative direct electrostimulation for quick and precise localization. Methods Five glioma patients with sensory cortex involvement by or next to the lesion had preoperative BOLD fMRI to determine the spatial relationship of cortical sensory areas to the tumours. Bilateral hand opposite movement was performed by these patients for fMRI. Precentral and postcentral gyri were identified by electrical stimulation during the operation. Karnofsky Performance Status scores of the patients＇ pre- and postoperative and the role of BOLD fMRI were evaluated. Results The cortical sensory areas were all activated in five glioma patients involving postcentral gyrus areas by BOLD fMRI with bilateral hand opposite movement. The detected activation areas corresponded with the results from cortical electrical stimulation. Conclusions The relationship between cortical sensory areas and tumour can be accurately shown by BOLD fMRI before operation. And the information used to make the tumour resection could obtain good clinical results.     

Cerebral activation during unilateral clenching in patients with temporomandibular joint synovitis and biting pain: an functional magnetic resonance imaging study

Background  Functional magnetic resonance is a non-invasive method that can examine brain activity and has been widely used in various fields including jaw movement and pain processing. Temporomandibular disorder (TMD) is one of the most frequent facial pain problems. The objective of this study was to investigate the brain activities using functional magnetic resonance imaging (fMRI) during unilateral maximal voluntary clenching tasks in the TMD synovitis patients with biting pain.

Methods  Fourteen TMD synovitis patients with unilateral biting pain and 14 controls were included in the study. Contralateral biting pain was defined as right molar clenching causing left temporomandibular joint (TMJ) pain. Ipsilateral biting pain was defined as right molar clenching causing right TMJ pain. Symptom Check List-90 (SCL-90) was administered to the patients and controls. Independent sample t-test was used to compare the SCL-90 subscales between the two groups. Unilateral clenching tasks were performed by the patients and controls. Imaging data were analyzed using SPM99.

Results  Patients were divided into contralateral TMD biting pain group (n=8) and ipsilateral TMD biting pain group (n=6). The SCL-90 subscales were significantly different between the two groups for somatization, depression, anxiety, phobic anxiety, and paranoid ideation. Group analysis of the controls demonstrated brain activations in the inferior frontal gyrus, precentral gyrus, middle frontal gyrus, superior temporal gyrus, and insular. The areas of activation were different between right and left clenching task. In TMJ synovitis patients with contralateral or ipsilateral biting pain, the group analysis showed activations in the inferior frontal gyrus, superior temporal gyrus, medium frontal gyrus, precentral gyrus, and anterior cingulate cortex.

Conclusions  The inferior frontal gyrus and precentral gyrus play essential roles during the unilateral clenching task. Activation of anterior cingulate cortex in the synovitis patients with biting pain was associated with higher levels of psychological distress.

     

睡眠剥夺后类比推理认知功能改变的功能性磁共振成像初步分析(英文)

目的研究睡眠剥夺后类比推理认知功能改变在功能性磁共振成像上的表现。方法对30例健康志愿者(男性18例,女性12例,平均年龄40岁)进行2次类比推理功能磁共振成像扫描,分别于正常睡眠情况下和睡眠剥夺24小时后,扫描顺序是制衡的。数据处理由统计参数图及功能性神经影像分析软件完成。结果 24小时的睡眠剥夺没有显著性地改变人脑类比推理活动,包括双前额叶及顶叶区的活动。结论睡眠剥夺后人脑类比推理可能存在代偿机制。     

维持手肌张力功能磁共振成像研究

目的:运用fMRI技术观察右利手志愿者在单手握拳维持一定肌张力情况下脑功能区的激活情况。方法:对13名志愿者分别进行左右手持续握拳维持肌张力下的fMRI实验。采用SPM99对fMRI数据进行后处理及功能区定位。结果:右手握拳维持肌张力激活左侧初级运动皮层区(primarymotorcortex,M1)、初级体感觉皮层(primarysenso-rycortex,S1)及右侧小脑半球。左手握拳维持肌张力激活右侧M1及S1,右侧辅助运动区(supplementarymotorarea,SMA)和左侧小脑半球。结论:握拳维持一定静态肌张力状态下的脑部激活情况与动态弹指运动相似,但初级感觉皮层也明显激活,运动前区无激活。各功能区协同作用,参与对肌张力的维持。     

运动准备和执行的事件相关功能磁共振研究

目的:应用事件相关功能磁共振成像技术研究参与运动准备和执行的脑区的激活特点.方法:应用事件相关功能磁共振成像技术记录12名右利手健康受试者在序列手指运动过程中运动准备与运动执行大脑皮层的功能活动.采用美国威斯康辛医学院AFNI软件包进行每个像素的血氧变化分析,作出与运动准备和运动执行有关的脑激活图.结果:与运动准备有关的激活主要集中在双侧运动前区(PMC)前部,双侧后顶叶(PPC)后部;与执行有关的激活区主要集中在对侧初级运动区(M1),双侧辅助运动区(SMA)本部;而双侧辅助运动区前部、双侧运动前区后部在运动准备与执行过程中均有激活.结论:人脑内与运动相关的脑区功能并非单一.     

脑卒中后运动神经网络重组的横向功能磁共振研究

目的利用功能磁共振成像研究运动功能不同程度恢复卒中患者被动运动任务时大脑的激活差异。方法对20例卒中患者分别行双侧腕关节被动运动的功能MRI扫描,采用SPM2软件进行数据分析和脑功能区定位。结果不同恢复程度的卒中患者患肢腕关节被动运动激活脑区不同:恢复较好者,以对侧感觉运动区(SMC)、同侧小脑、双侧辅助运动区(SMA)激活显著;恢复不好者,远隔部位激活较显著。患者健肢激活脑区及面积均未见明显差异。结论对侧SMC及SMA对运动功能恢复起至关重要的作用;健侧大脑半球的代偿作用对患肢运动功能的恢复影响较大。     

参与随意运动脑区的一侧化分布

目的:系统研究右利手被试者执行右手手指序列运动时,全脑运动有关区域的一侧化特点.方法:利用事件相关功能磁共振成像(fMRI)技术,结合右手手指的序列运动任务,研究8名右利手被试者脑区激活的一侧化特点.使用AFNI软件的反卷积程序生成激活图,计算一侧化指数并进行统计检验.结果:所有运动脑区,包括先前认为只与运动准备有关的区域,都参加了执行过程.从激活图上看,大脑各运动区激活呈左侧化,小脑激活呈右侧化特点.进一步的统计检验发现,大脑的初级运动区(M1)、辅助运动区(SMA)、后顶叶(PPC)激活呈左侧化趋势,运动前区(PMC)、扣带回、基底神经节(BG)一侧化不明显,小脑呈右侧化.结论:虽然运动脑区激活的一侧化特点在个体间表现细微的差别,但仍可见一侧化趋势.以往研究只在个别区域观察到一侧化激活特点,可能与任务难度和实验设计方式等有关.     

实时功能磁共振成像技术对运动皮层的定位探讨

目的：探讨运动皮层实时脑功能的成像技术和Functool,ICA和SPM的后处理技术。方法：15例正常志愿者进行23次对指运动实时脑功能扫描,经Functool,IAC和SPM软件后处理成像,并对3种软件的成像进行分析。结果：Functool处理后,23次实时脑功能成像显示了手指运动对侧初级皮层运动区/感觉区（M1/S1）、辅助运动区（SMA）明显激活,同侧激活区较小或者未见激活区。双侧小脑皮质有明显激活,同侧较大。5次运动前区双侧有激活,4次对侧有较小激活区。12次ICA,SPM所获图像与相应的Functool图像一致。结论：实时脑功能成像能对全脑进行实时扫描,Functool,ICA和SPM后处理能够较好地显示相应的脑运动皮层激活区。     

运动准备和执行的全脑功能磁共振研究

目的研究各运动相关脑结构在运动准备和执行过程中作用。方法采用事件相关功能磁共振成像技术对12名右利手健康受试者在延时序列手指运动过程中全脑的功能活动进行记录,作出与运动准备和运动执行有关的脑激活图以及时间信号强度反应曲线。结果与运动准备有关的激活主要集中在双侧运动前区（PMC）前部,双后顶叶（PPC）,双侧辅助运动区（SMA）前部;与执行有关的激活区主要集中在对侧初级运动区（M1）,双侧辅助运动区（SMA）体部,小脑皮层在运动准备及执行过程中均有激活。而从基于单像素分析的时间信号强度反应曲线表明上述区域在运动准备及执行过程中均有不同程度的激活,但在不同的脑区有不同的分布特点。结论人脑运动相关区域不同程度地参与了运动准备与运动执行,但靠近初级运动皮层的初级运动区以参与运动的执行为主,而属远离初级运动区的次级运动皮层则更多参与了运动的准备过程。     

小脑语言功能的fMRI初步评价

目的利用磁共振功能成像（fMRI）技术初步探讨小脑的语义辨别功能。方法共9名受试者参加实验，fMRI刺激模式为Block Design，刺激材料通过听觉呈现，基线静息期要求受试者被动听机器扫描时的声音，以此作为控制任务。共进行两次实验，实验1任务期要求受试者仔细听无意义假词词组。实验2任务期要求听真词词组，并对词性（具体词还是抽象词）做出心理判断。结果所有受试者均完成了实验要求，且头动范围小于一个像素大小。fMRI实验1激活的脑区包括：双侧颞上回（包括Brodmann第22区、42区）、双侧额下回、双侧运动区及左侧角回。fMRI实验2激活的脑区包括：双侧颞上回（包括Brodmann第22区、42区）、双侧额下回、双侧运动区及左侧角回、右侧小脑半球。在左侧额下回激活的强度和范围上，实验2明显〉实验1。结论f胀I对小脑语言功能研究具有很大的价值，通过9例正常人研究发现小脑的激活与词语语义辨别有关。     

高血压患者临床前认知损害的功能磁共振评价

目的利用磁共振功能成像（fMRI）技术,研究无心脑肾并发症以及认知障碍的中重度高血压患者是否存在认知相关的脑功能异常。方法50名受试者参加试验。中重度原发性高血压患者25例,正常对照25名,按性别、年龄及文化程度匹配。fMRI刺激模式为Block Design,刺激材料通过听觉呈现。实验1任务要求受试者仔细听无意义假词词组。实验2要求听真词词组,并对词性（具体词还是抽象词）做心理判断。fMRI数据处理用SPM99软件,获得基于单个像素分析的检验激活图及负激活图。结果简易智能状态检查,高血压组29．3±1．1、对照组29．6±0．5,两组分值差异无统计学意义（P=0．5223）。焦虑状态量表分值,患者组（47±5）高于对照组（42±5）（P=0．0356）。fMRI实验1：患者组与对照组相比,激活与负激活脑区部位基本相同,但是患者组有关脑区的活动强度强于正常对照组。fMRI实验2两组受试者激活与负激活脑区也相同,激活脑区包括两侧颞上回、额下回脑区;左侧角回;两侧额上回、运动前区;两侧辅助运动区及小脑半球等。负激活脑区包括前额叶中内侧、后带回后部／楔前叶、两侧顶下小叶及枕叶区域等。但患者组激活的强度与范围均大于对照组。结论无心脑肾并发症以及行为认知障碍的中重度高血压患者,可能已经存在某些脑功能异常,fMRI技术有可能早期检测到这些改变。