中英文语言活动区功能磁共振成像研究

目的初步探讨母语为中文者,说中文(L1)及英文(L2)时激活的语言相关功能区并比较其异同。方法对22例正常志愿者———“晚双语(13～15岁开始学英语)中国人,于说中文及英文两种状态下分别进行血氧水平依赖性增强效应磁共振脑功能成像检查,研究哪些语言相关脑功能区被激活,并比较两种状态下的脑激活区。结果说中文及英文时分别激活了不完全相同的脑区。说中文时激活的主要脑区包括:两侧运动区,左右侧额下回,左右侧颞上回,左侧岛叶及左右侧小脑半球。说英文时激活的脑区包括:左侧额下回,左侧颞上回,左侧岛叶及左右侧小脑半球。比较显示中文任务可激活右侧颞上回,而英文任务未激活这些区域。结论中英文“晚双语”者,两种语言激活的脑区不完全相同。说中文时激活的脑区要比说英文时较广泛。这主要在右侧大脑半球的右额下回及右颞上回。     

Developmental changes in neural activation and psychophysiological interaction patterns of brain regions associated with interference control and time perception

Interference control and time perception are mediated by common neural networks, including the frontal and parietal lobes, the cerebellum and the basal ganglia. Previous studies have shown that while time perception develops early in life, interference control seems to follow a protracted course of maturation into late adolescence. Thus, the current study examined developmental changes in neural activation and functional interaction between brain regions during a combined time discrimination and interference control task using fMRI. Thirty-four participants, aged 8-15 years, were scanned while performing a spatial stimulus response compatibility (SRC) task and a time discrimination (TD) task using identical stimuli. We found shared neural activation in a fronto-parieto-cerebellar network as well as task-specific patterns of psychophysiological interaction with positive coupling between the right inferior frontal gyrus (IFG), the superior parietal lobes bilaterally, the contralateral IFG and the thalamus during interference control and positive interactions between the right IFG and bilateral cerebellar activity and the thalamus during time discrimination. Developmental changes in task performance and brain activation patterns were only observed during the SRC task, with increased neural activity in the left inferior parietal gyrus and positive coupling between fronto-parietal brain regions that was only observed in the adolescents group. These results suggest that although both cognitive tasks rely on a shared neural network, distinct developmental curves of brain activation and connectivity could be observed associated with differential maturation patterns underlying cognitive development.     

不出声与出声图片命名任务神经激活机制差异的功能磁共振成像

目的 采用功能磁共振成像(fMRI)技术观察执行不出声和出声图片命名任务时大脑活动的差异.方法 在10名健康志愿者(24～27岁)分别进行不出声和出声图片命名时,同时采集其脑部的fMRI数据,通过分析处理获得执行不同任务时的头动结果及脑功能区统计激活图.结果 不出声任务的平均头动和最大头动低于出声任务,但差异无统计学意义(P=0.23).不出声图片命名的神经激活网络包括双侧枕回及小脑、双侧辅助运动区、中央后回、双侧额下回和前扣带回.出声图片命名时除在上述不出声时的激活区有更强激活外,还激活了双侧中央前回(BA4)、双侧后上颞回、左侧前上颞回、双侧丘脑及基底节区、左侧岛叶.结论 不出声和出声图片命名的神经处理网络及环节互不相同,两种任务不能相互替代.     

不同频率rTMS对脑卒中后中-重度运动性失语患者语言功能恢复的影响及机制

目的 探讨不同频率重复经颅磁刺激（rTMS）对恢复期脑卒中后中-重度运动性失语患者语言功能恢复的影响及机制。方法 纳入恢复期脑卒中后中-重度运动性失语患者30例,将其分为对照组、低频组（1 Hz rTMS）和高频组（10 Hz rTMS）各10例,3组均进行常规语言训练;低频、高频组予右侧额下回三角部相应频率rTMS治疗后再进行常规语言训练。采用中文版西方失语症成套检验（WAB）及任务态功能磁共振成像（fMRI）检测治疗前后语言水平差异以及脑区激活、激活体素指数（AVI）变化。结果 治疗后,3组患者的听理解、复述、失语商（AQ）值较治疗前改善（P均< 0.05）,且低频、高频组的自发言语、命名得分也较治疗前改善（P均< 0.05）;与对照组比较,低频组复述、命名、AQ值改善更明显（P均< 0.05）,高频组自发言语、听理解、命名、AQ值改善更明显（P均< 0.05）;与低频组比较,高频组自发言语、听理解改善更明显（P均< 0.05）。治疗后,3组患者AVI结果提示语言偏侧化半球均由治疗前的右侧转为左侧;fMRI结果显示双侧大脑半球均存在激活升高、降低的语言相关感兴趣区（ROI）、非感兴趣区,但以左侧大脑半球参与语言感知、语义理解和表达的ROI激活升高为主;低频组左侧大脑半球AVI增加（P < 0.05）,右侧额下回三角部受抑制后未出现左侧额下回三角部激活升高;高频组治疗后双侧大脑半球AVI均升高（P均< 0.05）,双侧额下回三角部等语言相关ROI激活升高。结论 低频、高频rTMS均有利于改善脑卒中后中-重度运动性失语患者语言功能,高频rTMS的效果优于低频rTMS。低频rTMS通过增加高效语言功能区的激活,优化失语患者语言功能重组模式;高频rTMS增强了右侧大脑半球的代偿作用,同时在促进左侧大脑半球激活重组中发挥了作用。     

Overt and imagined singing of an Italian aria

Activation maps of 16 professional classical singers were evaluated during overt singing and imagined singing of an Italian aria utilizing a sparse sampling functional magnetic imaging (fMRI) technique. Overt singing involved bilateral primary and secondary sensorimotor and auditory cortices but also areas associated with speech and language production. Activation magnitude within the gyri of Heschl (A1) was comparable in both hemispheres. Subcortical motor areas (cerebellum, thalamus, medulla and basal ganglia) were active too. Areas associated with emotional processing showed slight (anterior cingulate cortex, anterior insula) activation. Cerebral activation sites during imagined singing were centered on fronto-parietal areas and involved primary and secondary sensorimotor areas in both hemispheres. Areas processing emotions showed intense activation (ACC and bilateral insula, hippocampus and anterior temporal poles, bilateral amygdala). Imagery showed no significant activation in A1. Overt minus imagined singing revealed increased activation in cortical (bilateral primary motor; M1) and subcortical (right cerebellar hemisphere, medulla) motor as well as in sensory areas (primary somatosensory cortex, bilateral A1). Imagined minus overt singing showed enhanced activity in the medial Brodmann's area 6, the ventrolateral and medial prefrontal cortex (PFC), the anterior cingulate cortex and the inferior parietal lobe. Additionally, Wernicke's area and Brocca's area and their homologues were increasingly active during imagery. We conclude that imagined and overt singing involves partly different brain systems in professional singers with more prefrontal and limbic activation and a larger network of higher order associative functions during imagery.     

The effect of stimulus-response compatibility on cortical motor activation

Stimulus-response compatibility (SRC) is a general term describing the relationship between a triggering stimulus and its associated motor response. The relationship between stimulus and response can be manipulated at the level of the set of stimulus and response characteristics (set-level) or at the level of the mapping between the individual elements of the stimulus and response sets (element-level). We used functional magnetic resonance imaging (fMRI) to investigate the effects of SRC on functional activation in cortical motor areas. Using behavioral tasks to separately evaluate set- and element-level compatibility, and their interaction, we measured the volume of functional activation in 11 cortical motor areas, in the anterior frontal cortex, and in the superior temporal lobe. Element-level compatibility effects were associated with significant activation in the pre-supplementary motor area (preSMA), the dorsal (PMd) and ventral (PMv) premotor areas, and the parietal areas (inferior, superior, intraparietal sulcus, precuneus). The activation was lateralized to the right hemisphere for most of the areas. Set-level compatibility effects resulted in significant activation in the inferior frontal gyri, anterior cingulate and cingulate motor areas, the PMd, PMv, preSMA, the parietal areas (inferior, superior, intraparietal sulcus, precuneus), and in the superior temporal lobe. Activation in the majority of these areas was lateralized to the left hemisphere. Finally, there was an interaction between set and element-level compatibility in the middle and superior frontal gyri, in an area co-extensive with the dorsolateral prefrontal cortex, suggesting that this area provided the neural substrate for common processing stages, such as working memory and attention, which are engaged when both levels of SRC are manipulated at once.     

Differentiation between external and internal cuing: an fMRI study comparing tracing with drawing

Externally cued movement is thought to preferentially involve cerebellar and premotor circuits whereas internally generated movement recruits basal ganglia, pre-supplementary motor cortex (pre-SMA) and dorsolateral prefrontal cortex (DLPFC). Tracing and drawing are exemplar externally and internally guided actions and Parkinson's patients and cerebellar patients show deficits in tracking and drawing, respectively. In this study we aimed to examine this external/internal distinction in healthy subjects using functional imaging. Ten healthy subjects performed tracing and drawing of simple geometric shapes using pencil and paper while in a 3-T fMRI scanner. Results indicated that compared to tracing, drawing generated greater activation in the right cerebellar crus I, bilateral pre-SMA, right dorsal premotor cortex and right frontal eye field. Tracing did not recruit any additional activation compared to drawing except in striate and extrastriate visual areas. Therefore, drawing recruited areas more frequently associated with cognitively challenging tasks, attention and memory, but basal ganglia and cerebellar activity did not differentiate tracing from drawing in the hypothesised manner. As our paradigm was of a simple, repetitive and static design, these results suggest that the task familiarity and the temporal nature of visual feedback in tracking tasks, compared to tracing, may be important contributing factors towards the degree of cerebellar involvement. Future studies comparing dynamic with static external cues and visual feedback may clarify the role of the cerebellum and basal ganglia in the visual guidance of drawing actions.     

Cortical systems associated with covert music rehearsal

Musical representation and overt music production are necessarily complex cognitive phenomena. While overt musical performance may be observed and studied, the act of performance itself necessarily skews results toward the importance of primary sensorimotor and auditory cortices. However, imagined musical performance (IMP) represents a complex behavioral task involving components suited to exploring the physiological underpinnings of musical cognition in music performance without the sensorimotor and auditory confounds of overt performance. We mapped the blood oxygenation level-dependent fMRI activation response associated with IMP in experienced musicians independent of the piece imagined. IMP consistently activated supplementary motor and premotor areas, right superior parietal lobule, right inferior frontal gyrus, bilateral mid-frontal gyri, and bilateral lateral cerebellum in contrast with rest, in a manner distinct from fingertapping versus rest and passive listening to the same piece versus rest. These data implicate an associative network independent of primary sensorimotor and auditory activity, likely representing the cortical elements most intimately linked to music production.     

Cerebellar contributions to episodic memory encoding as revealed by fMRI

Event-related functional Magnetic Resonance Imaging (fMRI) allows for the comparison of hemodynamic responses evoked by items that are remembered in a subsequent memory task vs. items that are forgotten. In this way, brain regions that assumingly contribute to successful memory encoding have been identified, including the left inferior prefrontal cortex (LIPC) and the medial temporal lobe. Although a cerebellar involvement in verbal working memory is well-established, a contribution of the cerebellum to episodic long-term encoding has only sporadically been described, and mechanisms underlying cerebellar memory effects are unclear. We conducted a typical incidental verbal memory fMRI experiment with three different encoding tasks varying the depth of semantic processing. Slice positioning allowed for the coverage of the entire cerebellum. We observed a significant subsequent memory effect within the superior and posterior right cerebellar hemisphere that was task independent. Additionally, we found a different area within the superior right cerebellum displaying a memory effect specifically for semantically processed words and a bilateral cerebellar activation specifically associated with encoding success only for a non-semantic task. Our results suggest that besides its known role in verbal working memory, the cerebellum contributes to episodic long-term encoding and should therefore be considered in future fMRI studies dealing with episodic memory.     

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     

Differential components of sentence comprehension: beyond single word reading and memory

A number of studies have used functional neuroimaging to examine the neural mechanisms of sentence comprehension; however, few fMRI studies have examined activation patterns associated with sentence comprehension after accounting for activation attributable to single-word-level tasks important for sentence comprehension. To investigate the patterns of activation associated with sentence comprehension after controlling for single word reading and maintaining single words in memory, 20 unimpaired adult readers completed a block design paradigm which included sentence comprehension, single word reading, and short-term memory (for words) tasks. Results indicated that, regardless of the aspect of sentence comprehension being controlled for, activation was observed in bilateral temporal lobes (left > right) as well as bilateral occipital lobes and middle frontal gyri. Additional findings showed that bilateral superior parietal lobe activation was greatest for short-term memory for words, while left anterior inferior frontal gyri activation (centered around Brodmann's area 47) was greatest for single word reading. Results suggest that temporal cortex (left > right) is a core region important for sentence comprehension beyond the short-term memory and semantic requirements inherent in processing sentences.     

Event-related functional MRI investigation of vocal pitch variation

Voice production involves precise, coordinated movements of the intrinsic and extrinsic laryngeal musculature. A component of normal voice production is the modification of pitch. The underlying neural networks associated with these complex processes remains poorly characterized. However, several investigators are currently utilizing neuroimaging techniques to more clearly delineate these networks associated with phonation. The current study sought to identify the central cortical mechanism(s) associated with pitch variation during voice production using event-related functional MRI (fMRI). A single-trial design was employed consisting of three voice production tasks (low, comfortable, and high pitch) to contrast brain activity during the generation of varying frequencies. For whole brain analysis, volumes of activation within regions activated during each task were measured. Bilateral activations were shown in the cerebellum, superior temporal gyrus, insula, precentral gyrus, postcentral gyrus, inferior parietal lobe, and post-cingulate gyrus. In the left hemisphere, activations in the medial and middle frontal gyri were also observed. Regions active during high pitch production when compared to comfortable pitch were evident in the bilateral cerebellum, left inferior frontal gyrus, left cingulate gyrus, and left posterior cingulate. During low pitch generation, activations were present in the inferior frontal gyrus, insula, putamen, and cingulate gyrus in the left hemisphere. The inferior frontal gyrus in the right hemisphere produced greater activity than the area of the left hemisphere during high and low pitch generation. These results suggest that a single-trial design is sensitive enough to begin to delineate a widespread network of activations in both hemispheres associated with vocal pitch variation.     

功能磁共振观察额叶癫痫患者静息态局域一致性

目的 探讨静息状态下额叶癫痫(FLE)患者局域一致性(ReHo)的变化特点.方法 对46例常规结构MRI阴性FLE患者及性别年龄无差异的正常对照组行静息态fMRI,比较 ReHo改变脑区,观察ReHo改变脑区与FLE病程长短的相关性.结果 相比正常对照组,FLE患者ReHo值升高的脑区包括前、中扣带回,双侧岛叶、丘脑及右侧基底核区,ReHo降低脑区包括左侧额上回,左侧颞中、下回及小脑.相关性分析结果显示,FLE患者前、中扣带回,额上回ReHo值与病程长短呈正相关,双侧辅助运动区、右侧枕叶ReHo值与病程呈负相关.结论 FLE患者静息态下脑功能异常,扣带回、岛叶、丘脑及基底核区等区域存在ReHo改变.     

The neural correlates and functional integration of cognitive control in a Stroop task

It is well known that performance on a given trial of a cognitive task is affected by the nature of previous trials. For example, conflict effects on interference tasks, such as the Stroop task, are reduced subsequent to high-conflict trials relative to low-conflict trials. This interaction effect between previous and current trial types is called "conflict adaptation" and thought to be due to processing adjustments in cognitive control. The current study aimed to identify the neural substrates of cognitive control during conflict adaptation by isolating neural correlates of reduced conflict from those of increased cognitive control. We expected cognitive control to be implemented by prefrontal cortex through context-specific modulation of posterior regions involved in sensory and motor aspects of task performance. We collected event-related fMRI data on a color-word naming Stroop task and found distinct fronto-parietal networks of current trial conflict detection and conflict adaptation through cognitive control. Conflict adaptation was associated with increased activity in left middle frontal gyrus (GFm) and superior frontal gyrus (GFs), consistent with increased cognitive control, and with decreased activity in bilateral prefrontal and parietal cortices, consistent with reduced response conflict. Psychophysiological interaction analysis (PPI) revealed that cognitive control activation in GFs and GFm was accompanied by increased functional integration with bilateral inferior frontal, right temporal and parietal areas, and the anterior cerebellum. These data suggest that cognitive control is implemented by medial and lateral prefrontal cortices that bias processes in regions that have been implicated in high-level perceptual and motor processes.     

99mTc-ECD SPECT SPM分析健康成人控尿状态下局部脑血流变化

目的 应用99mTc-双半胱乙酯(ECD)SPECT脑血流断层显像研究健康成人静息状态和控尿状态下脑血流的差异,定位控尿相关的大脑功能区.方法 对16名健康志愿者在静息状态下(排空膀胱)行SPECT脑血流断层显像后,注射呋塞米,在膀胱充盈状态应用同等条件再次显像,前后两次采集数据相减,获得控尿状态图像.采用统计参数图(SPM)软件进行分析.结果 在控尿状态下,右侧顶叶、双侧额上回、右侧额下回和右侧颞上回、左侧屏状核的脑血流明显增高.结论 正常生理状态下,大脑控尿与右侧顶叶、双侧额上回、右侧额下回、右侧颞上回和左侧屏状核密切相关.联合应用SPECT脑功能显像及SPM分析软件可以更方便、快捷地定位大脑功能区.     

汉字与英文字形辨认的脑功能磁共振成像初步研究

目的:探讨功能磁共振成像(fMRI)技术研究人脑汉字与英文字形辨认方面的价值。材料与方法:12例(男5例,女7例)母语为汉语且裸眼视力正常的大学生参加实验。设备为GE Signa 1.5T MR仪,采用EPI序列,BOLD法行脑功能磁共振扫描。实验任务分别将汉字与英文(真字、假字、非字)投射到屏幕上,受试者通过头线圈反光镜观看屏幕并辨认。数据分析使用SPM 99升级软件,经过数据采集、预处理和建立模型显示结果。结果:汉字真字刺激在左额叶、中央前回(BA6)及枕叶(BA18)显著激活;左顶叶、中央后回(BA3)、右额下回(BA9)及双侧颞叶少量激活。英文真字刺激时左额中回、中央前回、左额下回显著激活;左颞梭状回(BA37)、右枕语言回(BA18)及左顶叶(BA40)也有激活。汉字和英文假字与非字只引起少量激活(P>0.05)。汉字与英文刺激左大脑半球的激活体积明显大于右半球;除枕叶外,英文在额、颞及顶叶引起的激活体积均大于汉字。结论:fMRI是研究人脑汉字和英文语言加工理想的无创性影像学方法,其脑加工优势半球均为左半球;母语为汉语者,其英文脑处理过程需更多的脑活动来参与和完成。     

Cerebrocerebellar networks during articulatory rehearsal and verbal working memory tasks

Converging evidence has implicated the cerebellum in verbal working memory. The current fMRI study sought to further characterize cerebrocerebellar participation in this cognitive process by revealing regions of activation common to a verbal working task and an articulatory control task, as well as regions that are uniquely activated by working memory. Consistent with our model's predictions, load-dependent activations were observed in Broca's area (BA 44/6) and the superior cerebellar hemisphere (VI/CrusI) for both working memory and motoric rehearsal. In contrast, activations unique to verbal working memory were found in the inferior parietal lobule (BA 40) and the right inferior cerebellum hemisphere (VIIB). These findings provide evidence for two cerebrocerebellar networks for verbal working memory: a frontal/superior cerebellar articulatory control system and a parietal/inferior cerebellar phonological storage system.     

Continuous ASL perfusion fMRI investigation of higher cognition: quantification of tonic CBF changes during sustained attention and working memory tasks

Arterial spin labeling (ASL) perfusion fMRI is an emerging method in clinical neuroimaging. Its non-invasiveness, absence of low frequency noise, and ability to quantify the absolute level of cerebral blood flow (CBF) make the method ideal for longitudinal designs or low frequency paradigms. Despite the usefulness in the study of cognitive dysfunctions in clinical populations, perfusion activation studies to date have been conducted for simple sensorimotor paradigms or with single-slice acquisition, mainly due to technical challenges. Using our recently developed amplitude-modulated continuous ASL (CASL) perfusion fMRI protocol, we assessed the feasibility of a higher level cognitive activation study in twelve healthy subjects. Taking advantage of the ASL noise properties, we were able to study tonic CBF changes during uninterrupted 6-min continuous performance of working memory and sustained attention tasks. For the visual sustained attention task, regional CBF increases (6-12 ml/100 g/min) were detected in the right middle frontal gyrus, the bilateral occipital gyri, and the anterior cingulate/medial frontal gyri. During the 2-back working memory task, significantly increased activations (7-11 ml/100 g/min) were found in the left inferior frontal/precentral gyri, the left inferior parietal lobule, the anterior cingulate/medial frontal gyri, and the left occipital gyrus. Locations of activated and deactivated areas largely concur with previous PET and BOLD fMRI studies utilizing similar paradigms. These results demonstrate that CASL perfusion fMRI can be successfully utilized for the investigation of the tonic CBF changes associated with high level cognitive operations. Increased applications of the method to the investigation of cognitively impaired populations are expected to follow.     

The somatosensory representation of the human clitoris: An fMRI study

We studied the central representation of pudendal afferents arising from the clitoral nerves in 15 healthy adult female subjects using electrical dorsal clitoral nerve stimulation and fMRI. As a control body region, we electrically stimulated the right hallux in eight subjects. In a block design experiment, we applied bilateral clitoral stimulation and unilateral (right) hallux stimulation. Activation maps were calculated for the contrasts ‘electrical dorsal clitoral nerve stimulation versus rest’ and ‘electrical hallux stimulation versus rest’.A random-effect group analysis for the clitoral stimulation showed significant activations bilateral in the superior and inferior frontal gyri, insulae and putamen and in the postcentral, precentral and inferior parietal gyri (including the primary and secondary somatosensory cortices). No activation was found on the mesial surface of the postcentral gyrus. For the hallux, activations occurred in a similar neuronal network but the activation in the primary somatosensory cortex was localized in the inter-hemispheric fissure.The results of this study demonstrate that the central representation of pudendal afferents arising from the clitoral nerves and sensory inputs from the hallux can be studied and distinguished from each other by fMRI. From the somatotopic order described in the somatosensory homunculus one would expect for electrical clitoral nerve stimulation activation of the mesial wall of the postcentral gyrus. In contrast, we found activations on the lateral surface of the postcentral gyrus.     

静息态fMRI评估酒精注射急性期恒河猴脑功能改变

目的 采用静息态fMRI基于分数低频振荡幅度（fALFF）算法评价酒精急性期恒河猴脑功能改变。方法 分别对7只雄性健康恒河猴于给予酒精前（对照组）及10 min后（酒精组）行静息态fMRI扫描,采用fALFF算法获得两组fALFF值存在差异的脑区。结果 静息态下,酒精组fALFF值低于对照组的脑区为右枕叶、右侧颞中回、左侧中央后回、右侧楔叶/距状沟、右侧额上回、后扣带回及小脑、丘脑（P<0.01）;酒精组fALFF值高于对照组的脑区包括双侧额上回、双侧颞下回、右侧中央前回、楔前叶、后扣带回、左侧海马、双侧岛叶及脑干、小脑、右侧基底核（P均<0.01）。结论 酒精急性期恒河猴脑功能的改变具有全脑效应。