应用功能磁共振研究学习对复杂加法的影响

目的:应用功能磁共振(fMRI)对复杂加法的脑功能区进行研究,并分析学习记忆对复杂加法的影响。材料和方法:20名年轻成人右利手正常志愿者参加实验,任务采用组块设计,应用AFNI软件进行数据分析和功能定位,并比较学习前后的脑区激活结构。结果:在未学习复杂计算任务中,两侧枕叶视区、两侧额中回、两侧额叶内侧前部及中部(辅助运动区)、两侧额下回、左侧中央前回、两侧楔前叶、两侧顶间沟周围脑区、两侧顶下小叶、小脑出现激活。学习后复杂加法任务所显示的激活区域有:两侧枕叶视区、两侧额中回、左侧额下回、左侧中央前回、两侧辅助运动区、两侧顶上小叶和顶下小叶、两侧楔前叶。比较学习前后的脑区激活结构,学习前右侧额下回、左侧扣带回后部、左侧顶间沟周围脑区、左侧颞中回激活明显强于学习后;而学习后两侧楔前叶、两侧缘上回及右侧角回的激活相对增强。结论:学习能对复杂加法计算时神经网络功能活动方式产生影响,主要反映在前额叶和顶叶等与工作记忆相关脑区激活的改变上。     

珠心算儿童在额顶叶激活的fMRI研究

目的应用功能磁共振成像(fMRI)研究接受过和未接受过珠心算训练的儿童在进行加法和乘法时额顶叶激活区的差别,初步分析珠心算在儿童脑开发中的作用。方法 分别对24名接受过3年珠心算训练和12名未接受珠心算训练的儿童在加、乘计算和数物对照判断实验时进行BOLD-fMRI,应用SPM2软件对原始图像进行数据处理,获取执行不同任务的脑功能图。结果训练组的正确率均明显高于未训练组,平均反应时均短于未训练组。珠心算组与未训练组在进行计算时额顶叶的激活区有明显的不同,珠心算组比未训练组在前额叶的激活脑区明显减少(P0.05),而且顶叶的激活主要在顶上小叶后部/楔前叶,未训练组主要在顶下小叶。结论珠心算涉及多个脑功能区,各功能区可能在整体配合下完成任务,增强了特定脑区对信息的加工能力,有效提高脑区的利用效率,在儿童脑开发中起了重要的作用。     

阻塞性睡眠呼吸暂停综合征患者静息态下海马功能连接的fMRI研究

目的 采用种子点功能连接方法,分析阻塞性睡眠呼吸暂停综合征(OSAS)患者静息态下海马与全脑功能连接的改变,探索OSAS患者认知功能下降的神经生理机制.方法 40例OSAS患者及40例正常对照组(NC)进行静息态下脑功能磁共振成像(fMRI)数据采集.以左、右侧海马为种子点进行全脑的功能连接,采用两样本t检验比较组间功能连接差异.结果 与NC组比较,OSAS患者左侧海马与双侧楔前叶、额中回、前扣带回、中央前回及右侧后扣带回功能连接减低,而与双侧小脑后叶功能连接增高.OSAS患者右侧海马与双侧额中回、后扣带回、边缘叶及右侧楔前叶功能连接减低,而与左侧顶下小叶及右侧小脑后叶功能连接增高.结论 OSAS患者海马与多个脑区存在功能连接异常,可能是OSAS患者认知功能下降的神经机制.     

特发性全身性癫痫分数低频振幅及局部一致性的静息态f MR I研究

目的：观察特发性全身性癫痫(IGE)患者静息状态下全脑功能改变情况。方法采用3.0T MR扫描仪对23例 IGE患者(IGE组)及23例健康志愿者(对照组)行全脑3D 结构相及静息态功能磁共振成像(RS-fMRI)扫描,进行全脑分数低频振幅(fALFF)及局部一致性(ReHo)功能分析,并对比 IGE组相比对照组 fALFF及 ReHo 改变的脑区,分析 IGE 组差异脑区与患者病程的相关性。结果与正常对照组相比,IGE组 fALFF升高的脑区位于双侧中央前回、左侧辅助运动区、左侧扣带回、左侧中央旁小叶、左侧距状裂周围皮层、左侧枕上回、左侧枕中回及右侧楔前叶;fALFF降低的脑区位于双侧颞下回、右侧海马旁回、右侧岛叶、右侧楔前叶及左侧顶下小叶(P<0.005)。ReHo 升高的脑区位于左侧距状裂周围皮层、左顶上小叶、左中央后回及右中央前回;ReHo降低的脑区位于右侧梭状回、左侧豆状核、右侧额下回、右内侧额上回、左侧枕中回、右侧岛叶及双侧顶下小叶(P<0.005)。IGE组 fALFF及 ReHo的差异脑区与患者病程均无相关性。结论 IGE患者脑内广泛的脑区功能异常改变可能是 IGE复杂临床表现的神经病理基础。联合应用 RS-fMRI的2种分析方法能较全面地评价静息状态下脑功能状态的改变情况,为 IGE 神经病理生理机制的研究提供可靠的功能神经解剖学依据。     

帕金森病静息态脑功能成像研究

目的研究静息态脑功能成像在帕金森病(parkinson's disease,PD)中的应用。方法帕金森病患者29例和健康对照组33例行磁共振检查,扫描序列包括常规MRI平扫及静息态fMRI成像,通过比较两组之间局部一致性和低频振幅的差异,寻找PD患者发生功能异常的脑区,探讨PD尤其是非运动症状的发生机制。结果 PD组ReHo减低的区域主要位于双侧额叶(包括前额叶、额上回、额中回)、胼胝体和扣带回、左中央前回、右侧角回、右侧颞极、丘脑和左侧脑干;PD组ReHo增高的区域主要位于双侧顶叶(包括中央前回和中央后回)左顶下小叶和右楔叶。PD组ALFF减低的区域主要位于左侧额叶、右侧颞叶、右侧中脑及大脑脚、右侧脑桥、右侧小脑、右侧丘脑、胼胝体、双侧顶上小叶;PD组ALFF增高的区域主要位于左侧中央前回和中央后回、左侧岛叶、左侧壳核和左侧丘脑。结论静息态fMRI的局部一致性(ReHo)和低频振幅(ALFF)的方法能够显示PD功能异常的脑区,有助于研究PD的发生机制。     

学龄儿童数字计算的fMRI研究

目的应用功能磁共振成像(fMRI)技术,研究学龄儿童在执行计算任务时的脑功能状态及激活模式。方法对12名儿童进行加、减、乘、除计算和数物对照判断实验。采用组块设计模式,静息组块与刺激组块交替出现,循环3次。设备为Siemens公司Trio3.0T磁共振扫描仪及头部正交线圈,采用EPI序列进行BOLD脑功能磁共振成像。应用SPM2软件进行数据处理和脑功能区定位。结果4种计算实验均可见双侧额中回、右侧顶下小叶、右侧舌回和双侧小脑半球激活。加、减、除法计算中还引起右侧顶上小叶激活。右侧梭状回激活见于加、乘和除法计算。结论fMRI可以对儿童计算方面的脑功能区进行定位。儿童计算过程的优势半球有别于成人,大脑的右侧半球在儿童的计算中可能发挥着主要作用。     

珠心算训练儿童枕叶激活状态的fMRI研究

目的应用功能磁共振成像(fMRI)探讨接受过珠心算训练的儿童与未接受过珠心算训练儿童(对照组)在执行不同计算任务时枕叶的激活状态,从而明确枕叶在珠心算中可能的作用机制。方法分别安排接受过3年珠心算训练的儿童(16名)和未经训练的对照组儿童(16名)执行加、减、乘、除运算任务及数物对照实验,同时进行fMRI检查,应用SPM2软件对原始图像进行数据处理,对相关脑区进行定位,重点研究枕叶的激活状态。结果珠心算训练组与未训练组儿童在计算过程中枕叶的激活有所不同,训练组儿童双侧枕叶均可见激活,主要为楔叶的激活,也可见舌回的激活,未训练组儿童主要为舌回激活。两组儿童不同运算枕叶激活范围差异具有统计学意义(P<0.01)。结论枕叶在珠心算中参与了视觉空间策略的处理过程,枕叶的激活状态可能与其神经机制有关。     

肝性脊髓病患者自发脑活动局部一致性的变化

目的 探讨肝性脊髓病(HM)患者静息态下局部一致性(ReHo)的差异.方法 对22例HM患者及25例人口学特征匹配的健康对照组(HC)进行静息态功能磁共振成像(rs-fMRI)扫描,用处理软件获得ReHo数据,比较HM患者与正常人在静息状态下大脑ReHo的差异.结果 与HC相比,HM患者ReHo值降低的脑区有左侧颞中回、右侧梭状回、右侧楔前叶和左侧海马旁回,ReHo值升高的脑区有双侧扣带回、双侧中央旁小叶、双侧额中回、右侧中央前回、双侧岛叶、右侧额上回和左侧额下回.结论HM患者的若干脑区存在ReHo升高或降低,提示HM的病理生理机制并非只存在单一脑区的功能异常,而涉及多个大脑功能网络,是一种大脑功能失连接的表现.     

国人汉字书写神经基础的脑功能成像

目的:利用功能磁共振成像技术(fMRI),研究正常国人汉字书写功能的神经基础.材料和方法:采用GE公司Signa1.5T磁共振成像系统,对10名健康右利手母语为汉语的志愿者进行默读、复杂对指运动、抄写三个任务期间的功能活动进行了全脑扫描.数据经过空间平滑、头动矫正、卷积分析等处理,获得抄写减去默读、抄写减去对指之后脑功能激活图,统计出两者间共同的激活区.结果:主要共同激活区位于额顶叶皮质,包括左侧额中回,双侧顶上小叶,双侧顶下小叶,两侧额内侧回,左侧中央前、后回.结论:汉字的书写是双脑协同的过程,右侧大脑半球对汉字的书写尤其重要;书写功能涉及较多的皮质及皮质下结构,利用功能磁共振成像可以揭示这些结构在书写过程中的作用.     

珠心算加法练习对儿童心算影响的fMRI研究

目的 观察经过珠心算训练后的儿童计算时脑功能区激活的特点,研究珠心算训练对儿童心算的影响.方法 对12名经过3年珠心算训练的儿童以及与其年龄、性别等匹配的12名未接受过珠心算训练的儿童在加法计算时进行功能磁共振成像,同时记录其相关的行为学数据.应用SPM2软件对原始数据进行分析处理,对脑功能区进行定位.结果 珠心算组与对照组儿童的运算正确率分别为:(95.00±7.16)%、(74.26±16.07)%,反应时间分别为:(597.91±124.05)ms、(770.07±148.54)ms,其差异具有统计学意义(t=-4.084,P＜0.01;t=3.082,P＜0.01).脑功能成像显示对照组儿童激活的脑区较珠心算组的明显增多,主要位于额顶叶,珠心算组激活脑区较少,且范围较小,主要位于顶叶及枕叶.结论 珠心算练习可能会增强某些脑区对信息的加工能力,可有效提高脑区的利用效率.     

Effects of long-term practice and task complexity on brain activities when performing abacus-based mental calculations: a PET study

Purpose  The aim of this study was to examine the neural bases for the exceptional mental calculation ability possessed by Chinese abacus experts through PET imaging. Methods  We compared the different regional cerebral blood flow (rCBF) patterns using ¹⁵O-water PET in 10 abacus experts and 12 non-experts while they were performing each of the following three tasks: covert reading, simple addition, and complex contiguous addition. All data collected were analyzed using SPM2 and MNI templates. Results  For non-experts during the tasks of simple addition, the observed activation of brain regions were associated with coordination of language (inferior frontal network) and visuospatial processing (left parietal/frontal network). Similar activation patterns but with a larger visuospatial processing involvement were observed during complex contiguous addition tasks, suggesting the recruitment of more visuospatial memory for solving the complex problems. For abacus experts, however, the brain activation patterns showed slight differences when they were performing simple and complex addition tasks, both of which involve visuospatial processing (bilateral parietal/frontal network). These findings supported the notion that the experts were completing all the calculation process on a virtual mental abacus and relying on this same computational strategy in both simple and complex tasks, which required almost no increasing brain workload for solving the latter. Conclusion  In conclusion, after intensive training and practice, the neural pathways in an abacus expert have been connected more effectively for performing the number encoding and retrieval that are required in abacus tasks, resulting in exceptional mental computational ability.     

儿童额顶叶工作记忆任务的功能性磁共振成像研究

目的:联合应用血氧水平依赖(BOLD)-fMRI和扩散张量成像(DTI)两种功能磁共振成像技术,研究正常儿童工作记忆任务中额顶叶皮层激活强度与额顶叶各部位白质纤维束扩散特性之间的关系.方法:搜集健康志愿者12例,男女各6例,平均年龄11.4岁.以步进式视觉累加实验(PVSAT)作为刺激模式,对所有儿童进行BOLDfMR...     

脑功能MRI在青少年非自杀性自伤中的研究进展

非自杀性自伤（NSSI）是指没有自杀意图且以自伤行为为主的精神障碍,脑功能MRI（fMRI）可揭示NSSI病人的异常脑活动特征。静息态fMRI的不同功能连接模式对NSSI的诊断和疗效评估具有重要价值,基于不同任务状态的fMRI的异常脑激活可评估NSSI病人的脑功能改变。就不同分析方法（基于种子点、独立成分分析和图论的分析方法）的静息态fMRI连接模式和不同任务状态（情绪、社交和奖赏任务）下fMRI的脑活动在NSSI中的研究进展予以综述。     

Memory lateralization with 2 functional MR imaging tasks in patients with lesions in the temporal lobe

BACKGROUND: Previous studies to determine memory lateralization with functional MR imaging (fMRI) have used encoding or recall tasks. The convergence between the results of both tasks, however, is unknown. OBJECTIVE: The objective of this study was to investigate hemispheric asymmetries of temporal lobe activity (parahippocampus and fusiform gyri) in patients with temporal lesions by using both kinds of fMRI tasks. METHODS: By using blood oxygenation level-dependent fMRI, hemispheric asymmetries of 25 consecutive patients admitted for presurgical evaluation of memory and 12 healthy control participants were studied. Activation was induced by using the picture-encoding task (processing of complex scenes) and the hometown-walking task (requiring mental navigation through one's hometown by using landmarks given by participants themselves). RESULTS: Results in the control group showed that both tasks activated the parahippocampus similarly. The picture-encoding task, however, yielded greater posterior activations in the parahippocampus than did the hometown-walking task. As observed in other studies, more than half the patients showed contralesional representation of memory in each task. It is important to note that estimated memory lateralization from each task was different in 30% of patients, and several cases showed clear discrepancies between both tasks. CONCLUSION: Although previous studies showed that both tasks were useful for evaluating memory lateralization, the present study suggested that the administration of both tasks is necessary for presurgical evaluation of memory lateralization in patients with lesions in the temporal lobe. Therefore, both encoding and recall processes should at least be considered in the evaluation of memory.     

Functional MR imaging study of language-related differences in bilingual cerebellar activation

BACKGROUND AND PURPOSE: Reports in the monolingual literature suggest that the cerebellum has an important role in language processing. The purpose of this study was to determine whether bilingual cerebellar functional MR imaging (fMRI) activation differs during the performance of comparable tasks in subjects' primary and secondary languages. METHODS: Eight bilingual, right-handed individuals underwent echo-planar fMRI at 1.5 T. They performed semantic (noun-verb association) and phonological (rhyming) tasks in Spanish (primary language) and English (secondary language). Individual and group functional datasets were analyzed using Statistical Parametric Mapping software (SPM99; P <.001 with a 10-voxel spatial extent threshold) and overlaid on T1-weighted anatomic images normalized to a standard (Montreal Neurologic Institute) space. Analysis of variance was performed on laterality indices derived from voxel counts in cerebellar regions of interest (ROIs). Subtraction of group-averaged normalized results from the combined Spanish tasks from the combined English tasks was also performed within SPM99 (P <.001 activation threshold). RESULTS: Significantly greater lateralilty indices were noted in the English tasks than in the Spanish tasks (mean Spanish LI, 0.3286; mean English LI, 0.5141 [P =.0143]). Overall, more robust activation was seen in the English tasks than in the Spanish tasks. Areas of significantly greater activation existed in the English tasks as compared with the Spanish tasks; these areas were more prominent in the left cerebellar hemisphere. CONCLUSION: Although both English and Spanish language tasks demonstrate left cerebellar dominance, English tasks demonstrate greater left hemispheric lateralization.     

Recovery from mild head injury in sports: evidence from serial functional magnetic resonance imaging studies in male athletes.

OBJECTIVE: To examine functional brain activation patterns before and after postconcussive symptoms (PCS) resolution. DESIGN: Prospective serial study with male athletes using functional magnetic resonance imaging (fMRI). SETTING: Hospital laboratory and imaging facility. PARTICIPANTS: 9 symptomatic concussed athletes who experienced persisting PCS at least 1 month postinjury and 6 healthy athletes. INTERVENTIONS: All athletes filled out a PCS checklist and underwent an fMRI session during which they performed a working-memory task. MAIN OUTCOME MEASUREMENTS: Behavioral outcomes were response speed and accuracy on the working memory tasks performed during the fMRI session. Functional imaging outcomes were blood oxygen level-dependent fMRI activation patterns associated with a working memory task. RESULTS:: There was no difference in behavioral performance between the groups. Despite normal structural MRI findings, all symptomatic concussed athletes initially showed atypical brain activation patterns in the dorsolateral prefrontal cortex (DLPC). Compared to the initial postinjury evaluation, those athletes at follow-up with PCS resolved showed significant increases in activation in the left DLPC. Concussed athletes whose PCS status remained unchanged at follow-up continued to show atypical activation in DLPC. Healthy athletes showed remarkably clear and consistent brain activations in DLPC initially as well as in follow-up, highlighting the test-retest reliability of fMRI. CONCLUSIONS: The results demonstrate the feasibility of using fMRI to detect an underlying pathology in symptomatic concussed athletes with normal structural imaging results and its potential to document recovery. Such information may be of considerable value for clinical judgment and patient management.     

Implementations of clinical functional magnetic resonance imaging using character-based paradigms for the prediction of Chinese language dominance

PURPOSE: Recently, functional MRI (fMRI) using word generation (WG) tasks has been shown to be effective for mapping the Chinese language-related brain areas. In clinical applications, however, patients' performance cannot be easily monitored during WG tasks. In this study, we evaluated the feasibility of a word choice (WC) paradigm in the clinical setting and compared the results with those from WG tasks. METHOD: Intrasubject comparisons of fMRI with both WG and WC paradigms were performed on six normal human subjects and two tumor patients. Subject responses in the WC paradigm, based on semantic judgments, were recorded. Activation strength, extent, and laterality were evaluated and compared. RESULTS: Our results showed that fMRI with the WC paradigm evoked weaker neuronal activation than that with the WG paradigm in Chinese language-related brain areas. It was sufficient to reveal language laterality for clinical use, however. In addition, it resulted in less nonlanguage-specific brain activation. CONCLUSION: Results from the patient data demonstrated strong evidence for the necessity of incorporating response monitoring during fMRI studies, which suggested that fMRI with the WC paradigm is more appropriate to be implemented for the prediction of Chinese language dominance in clinical environments.     

Mapping functionally related regions of brain with functional connectivity MR imaging

BACKGROUND AND PURPOSE: In subjects who are performing no prescribed cognitive task, functional connectivity mapped with MR imaging (fcMRI) shows regions with synchronous fluctuations of cerebral blood flow. When specific tasks are performed, functional MR imaging (fMRI) can map locations in which regional cerebral blood flow increases synchronously with the performance of the task. We tested the hypothesis that fcMRI maps, based on the synchrony of low-frequency blood flow fluctuations, identify brain regions that show activation on fMRI maps of sensorimotor, visual, language, and auditory tasks. METHODS: In four volunteers, task-activation fMRI and functional connectivity (resting-state) fcMRI data were acquired. A small region of interest (in an area that showed maximal task activation) was chosen, and the correlation coefficient of the corresponding resting-state signal with the signal of all other voxels in the resting data set was calculated. The correlation coefficient was decomposed into frequency components and its distribution determined for each fcMRI map. The fcMRI maps were compared with the fMRI maps. RESULTS: For each task, fcMRI maps based on one to four seed voxel(s) produced clusters of voxels in regions of eloquent cortex. For each fMRI map a closely corresponding fcMRI map was obtained. The frequencies that predominated in the cross-correlation coefficients for the functionally related regions were below 0.1 Hz. CONCLUSION: Functionally related brain regions can be identified by means of their synchronous slow fluctuations in signal intensity. Such blood flow synchrony can be detected in sensorimotor areas, expressive and receptive language regions, and the visual cortex by fcMRI. Regions identified by the slow synchronous fluctuations are similar to those activated by motor, language, or visual tasks.