正常中老年人词语联想任务功能磁共振成像研究

目的 采用功能磁共振成像(fMRI)技术对正常中老年人进行研究,检测与词语联想功能相关脑区的激活特点.方法 采用GE 1.5 T磁共振扫描仪对23例(男12例,女11例)正常中老年人行组块设计的词语联想任务fMRI研究.采用SPM 2软件进行数据处理和统计分析,通过组分析获得平均脑激活图,观察脑激活区的部位和激活强度.结果 12例符合入组条件,激活脑区为运动前区(PMC)、双侧额下回后部(Broca区及Broca镜像区)、双侧辅助运动区(SMA)、左侧顶后皮层、双侧岛叶、双侧扣带回前部、双侧基底节、左侧丘脑以及右侧小脑半球.全脑以左侧PMC激活强度最大.激活强度左侧大于右侧的脑区为额下回后部、背侧PMC及SMA;右侧大于左侧的脑区为腹侧PMC、岛叶、扣带回前部、基底节.结论 中老年人参与运动性语言表达的脑区,由包括Broca区在内的多个脑区组成复杂的神经网络,且相关脑区存在偏侧化现象,以左侧大脑半球和右侧小脑半球激活为主.     

健康成年人反复唾液吞咽测试期间的近红外脑功能成像

背景：吞咽是一种复杂的运动,吞咽的整个过程需要2个大脑半球皮质、脑干、特定的脑神经和咽部感受器之间的协同参与,而大脑皮质在吞咽过程中的作用及其对吞咽的影响仍然是一个待解决的问题。目的：使用功能性近红外光谱分析健康成年人反复唾液吞咽测试时大脑皮质的激活及偏侧化情况。方法：纳入27名健康成年人,其中男13名、女14名,年龄(20.41±1.66)岁,在功能性近红外光谱采集过程中进行反复唾液吞咽测试,分析该任务状态下的脑区激活情况,并计算激活脑区的偏侧化分布。结果与结论：(1)在反复唾液吞咽测试任务时,受试者双侧初级躯体感觉皮质、双侧初级运动皮质、双侧运动前区和辅助运动皮质区、双侧额下回三角部、双侧额极区及双侧背外侧前额叶均明显激活。半数以上受试者在反复唾液吞咽测试任务中存在大脑皮质半球的偏侧化,但大脑半球偏侧化存在较大变异性,且与受试者利手无明显关系。(2)将健康成年人作为受试者探究吞咽有关的激活区,能更准确地了解吞咽过程中的神经活动,对于进一步探究吞咽功能障碍具有重要意义。     

精神分裂症患者面孔知觉的功能磁共振成像

目的:探讨未服药的精神分裂症患者和健康对照者面孔知觉的脑区激活的差异。方法:本研究对10名未服药的精神分裂症患者(患者组)和10名年龄、教育程度和性别匹配的健康人(对照组)进行面孔知觉测试,应用功能磁共振成像(fMRI)技术,比较两组脑区激活区域的差异。结果:两组的面孔知觉任务平均反应时差异无显著性(1.32±0.29/1.28±0.18),但患者组的正确率低于对照组(47.9±24.4/71.3±14.9,t=2.62,P<0.05)。与对照组相比,患者组在面孔知觉时双侧梭状回、左丘脑部位激活降低。结论:精神分裂症患者双侧梭状回、左丘脑功能低下,是其面孔知觉功能受损的影像学证据。     

青少年肌阵挛癫痫发作间期EEG-fMRI的研究

采用同步脑电与功能磁共振(Simultaneous electroencephalography-correlated functional magnetic resonance imaging,EEG-fMRI)技术,研究青少年肌阵挛癫痫患者发作间期痫样放电时脑部血氧水平依赖(Blood oxygen level-dependent,BOLD)信号变化。结果发现:双侧大脑半球的激活及失活信号变化普遍对称且各自独立存在,信号由枕顶至额区逐渐减少。阳性激活区有:楔叶、岛叶、额中部内侧、小脑中线两侧及丘脑。阴性激活区有:双侧额前部、顶部及扣带后回。由此推断:以棘慢复合波为表现形式的同步的神经元活动可能反映了丘脑皮层BOLD信号的激活,而失活区域反映了异常放电时的脑功能的静息状态;这类激活在神经元的活动(EEG)与fMRI结果之间有很好的对应关系;EEG-fMRI是研究脑功能状态有效的方式。     

慢性创伤后应激障碍患者的脑功能磁共振研究

目的:探讨慢性创伤后应激障碍(post-traumatic stress disorder,PTSD)患者脑功能激活特征。方法:对17例矿难相关的慢性PTSD患者和14例经历相同矿难未患病的对照进行脑功能磁共振成像。使用Matlab6.5和SPM2软件对功能磁共振数据进行处理。结果:与对照组相比,患者组左海马旁回激活增强;右楔前叶激活降低。与中性图片相比,患者组面对负性图片时右海马旁回、右梭状回、右枕下回、双侧枕中回的激活增强;左顶下小叶、左顶上小叶、右中央后回、左楔叶、背外侧前额叶的激活降低。对照组面对负性图片时,右楔前叶激活增强;右岛叶激活降低。结论:这些脑区改变可能反映了PTSD患者症状包括对创伤情绪和记忆加工不足的复杂的生物学机制。     

脑梗死运动性失语患者语言任务fMRI功能连接初步研究

目的 对脑梗死运动性失语患者进行词语联想任务下的功能连接研究,探讨语言任务相关脑区在运动性失语后的功能连接变化形式及神经机制.方法 采用1.5 T磁共振扫描仪对10例脑梗死后运动性失语患者[均为男性,年龄43～77岁,平均(56.7±8.6岁)]及10名正常志愿者[均为男性,年龄46～74岁,平均(56.2±9.0)岁]行词语联想任务下的功能磁共振成像(fMRI)数据采集,应用SPM2,AFNI、Matlab软件进行预处理和统计分析,并根据正常人激活结果选择左侧额下回后部激活区作为功能连接的种子点,[中心区蒙特利尔神经研究所(MNI)坐标为“-51、9、21”],与全脑其他所有体素的时间序列做相关分析.采用单样本t检验和两样本t检验进行组内和组间分析,统计阈值设定为voxel＞ 30,P＜0.001(未校正).结果 对照组与种子点正相关的脑区主要包括左侧额下回、额中回、岛叶,左侧楔前叶、顶下小叶,左侧颞中回,左侧基底节,左侧丘脑,右侧额下回、额中回、岛叶,右侧颞下回、颞上回,双侧辅助运动区(SMA),右侧顶下小叶.患者组与种子点正相关的脑区主要包括左侧额下回后部、左岛叶,左侧中央后回,左侧顶下小叶.对照组与种子点的相关性大于患者组的脑区包括右侧颞中回、颞上回,右侧额下回,SMA.患者组与种子点的相关性大于对照组的脑区为左侧外侧裂周围区,包括左侧岛叶、左侧额下回.结论 .左侧额下回后部与右侧半球失去功能连接是运动性失语发生的一种神经机制.左侧外侧裂周围区对失语早期语言功能的维持有重要作用.     

无意识愤怒面孔加工的脑区激活似然估计(ALE)元分析

目的:了解无意识愤怒面孔加工的主要激活脑区及无意识情绪面孔加工的神经机制。方法:检索PubMed、Web of Science等数据库,要求:①使用愤怒面孔的无意识情绪加工fMRI研究;②采用Talairach和MNI坐标系统报告激活脑区。对符合要求的17篇文献使用GingerALE2.0软件计算脑区激活似然估计(ALE)值,得到脑区分布。结果:无意识愤怒面孔加工激活了双侧杏仁核,尤其是右侧。此外,左侧岛叶也有激活。结论:ALE元分析可以对fMRI研究结果进行整合分析,揭示了杏仁核在无意识情绪面孔加工中起到了重要作用。     

健康人大脑和小脑空间记忆认知功能的fMRI研究

本研究应用功能磁共振成像(functional magnetic resonance imaging,fMRI)技术,检测了健康人大脑和小脑参与空间记忆的认知过程。通过对10名右利手健康志愿者进行一项短时空间记忆任务作业的同时进行脑功能磁共振扫描,实验采用组块设计,任务与对照任务交替进行,数据采用SPM99软件进行数据分析和脑功能区定位。结果显示:当统计阈值设定为P<0.0001时,大脑皮层和右侧小脑一起被显著激活;大脑皮层所激活的脑区有双侧顶叶的楔前叶、顶上小叶、缘上回(BA7/40,BA:Brodma-nn Area),双侧前额上、中、下回(BA6/9/47),双侧枕叶和枕颞交界处(BA18/19/37),右侧海马回;左侧中脑黑质及被盖部也被激活。上述结果提示:小脑和大脑皮层一起参与了空间记忆的认知过程。     

精神分裂症患者异常脑网络的fMRI研究

目的:比较正常组和精神分裂症患者组执行工作记忆任务时的脑激活差别,探讨精神分裂症患者执行功能障碍的脑机制.方法:对16例正常对照和16例精神分裂症患者进行数字3-back工作记忆任务的fMRI检查和数据分析处理.结果:患者组出现两个激活方向相反的脑区网络,与正常组相比激活降低脑区为双侧DLPFC、VLPFC、LPMA、PPC、PFC嘴侧部和额极及左侧SMA;激活增加脑区为MPFC、双侧颞叶和双侧扣带回.结论:精神分裂症患者执行功能损害有相应的病理生理学基础,是多个脑区功能受损、脑网络连接障碍而非单一脑区受损,前额叶与海马/颞叶-边缘皮层间功能连接破坏可能是其中的一个原因.     

女性重性抑郁症患者识别动态面部表情的神经基础的fMRI研究

目的:利用事件相关设计的功能磁共振成像技术探讨汉族女性抑郁症患者明确和不明确识别动态面部表情的神经基础.方法:以15例女性重性抑郁症患者为病例组(抑郁组),与之相匹配的健康者为对照组,利用配对t检验比较两组在明确和不明确识别动态面部表情时激活脑区的差异,设对比有差异(P＜0.001,未校正)的体素范围(K值)≥10为具有显著性差异.结果:(1)与对照组相比,抑郁组在明确识别动态喜悦表情时右枕中回、右顶下小叶、左中央后回、右中央前回、右楔前叶活动增高,而右顶上小叶、左顶上小叶等区域活动降低;抑郁组在不明确识别动态喜悦表情时右顶下小叶活动增高,而右楔叶、右中央后回、左顶上小叶等区域活动降低.(2)与对照组相比,抑郁组在明确识别动态悲伤表情时右枕中回、左中央后回、左楔前叶活动增高,而左额中回活动降低;抑郁组在不明确识别动态悲伤表情时左梭状回、右中央前回、右楔前叶、左颞上回、左缘上回、边缘叶(两侧海马旁回、左后扣带回)、皮质下区以及中脑等区域活动增高,而右中央后回、颞叶等区域活动降低.结论:抑郁症患者和正常对照在识别喜悦情绪时,与情绪产生的相关脑区活动无明显差异,脑区激活的主要差异表现为明确状态下感知面部运动能力降低,而在不明确状态时却增强;而患者在识别悲伤表情时都表现为情绪产生相关脑区活动增强,而情绪调节相关脑区活动减弱,这种异常在无意识状态下(不明确条件下)更为明显.     

Cerebral areas processing swallowing and tongue movement are overlapping but distinct: a functional magnetic resonance imaging study

Although multiple regions of the cerebral cortex have been implicated in swallowing, the functional contributions of each brain area remain unclear. The present study sought to clarify the roles of these cortical foci in swallowing by comparing brain activation associated with voluntary saliva swallowing and voluntary tongue elevation. Fourteen healthy right-handed subjects were examined with single-event-related functional magnetic resonance imaging (fMRI) while laryngeal movements associated with swallowing and tongue movement were simultaneously recorded. Both swallowing and tongue elevation activated 1) the left lateral pericentral and anterior parietal cortex, and 2) the anterior cingulate cortex (ACC) and adjacent supplementary motor area (SMA), suggesting that these brain regions mediate processes shared by swallowing and tongue movement. Tongue elevation activated a larger total volume of cortex than swallowing, with significantly greater activation within the ACC, SMA, right precentral and postcentral gyri, premotor cortex, right putamen, and thalamus. Although a contrast analysis failed to identify activation foci specific to swallowing, superimposed activation maps suggested that the most lateral extent of the left pericentral and anterior parietal cortex, rostral ACC, precuneus, and right parietal operculum/insula were preferentially activated by swallowing. This finding suggests that these brain areas may mediate processes specific to swallowing. Approximately 60% of the subjects showed a strong functional lateralization of the postcentral gyrus toward the left hemisphere for swallowing, whereas 40% showed a similar activation bias for the tongue elevation task. This finding supports the view that the oral sensorimotor cortices within the left and right hemispheres are functionally nonequivalent.     

The neural basis of motor sequencing: an fMRI study of healthy subjects

The present study used functional MRI to clarify the brain regions activated during a series of motor sequencing tasks in healthy volunteers. Ten subjects were scanned while performing three soft signs tasks ranging from simple (PT: palm tapping), moderate (PS: pronation/supination) to complex movements (FEP: fist-edge-palm). The FEP task induced significant activations within the cortical networks including bilateral sensorimotor, SMA, left parietal, and right cerebellum, but no activation in the prefrontal area. Moreover, the percentage signal changes within the left sensorimotor, left thalamus and right cerebellum showed an increase in activation with task complexity. The present findings challenge the traditional belief that FEP was a task for frontal lobe function but suggest that successful performance of more complex neurological soft sign tasks like FEP requires the participation of more brain areas than simple motor sequencing and coordination task like PS and PT. These also provide the empirical data on the neural basis of neurological soft signs for further study in other clinical group like schizophrenia in the near future.     

Identification of the cerebral loci processing human swallowing with H2(15)O PET activation

Lesional and electrophysiological data implicate a role for the cerebral cortex in the initiation and modulation of human swallowing, and yet its functional neuroanatomy remains undefined. We therefore conducted a functional study of the cerebral loci processing human volitional swallowing with 15O-labeled water positron emission tomography (PET) activation imaging. Regional cerebral activation was investigated in 8 healthy right handed male volunteers with a randomized 12-scan paradigm of rest and water swallows (5 ml/bolus, continuous infusion) at increasing frequencies of 0.1, 0.2, and 0.3 Hz, which were visually cued and monitored with submental electromyogram (EMG). Group and individual linear covariate analyses were performed with SPM96. In five of eight subjects, the cortical motor representation of pharynx was subsequently mapped with transcranial magnetic stimulation (TMS) in a posthoc manner to substantiate findings of hemispheric differences in sensorimotor cortex activation seen with PET. During swallowing, group PET analysis identified increased regional cerebral blood flow (rCBF) (P < 0.001) within bilateral caudolateral sensorimotor cortex [Brodmann's area (BA) 3, 4, and 6], right anterior insula (BA 16), right orbitofrontal and temporopolar cortex (BA 11 and 38), left mesial premotor cortex (BA 6 and 24), left temporopolar cortex and amygdala (BA 38 and 34), left superiomedial cerebellum, and dorsal brain stem. Decreased rCBF (P < 0.001) was also observed within bilateral posterior parietal cortex (BA 7), right anterior occipital cortex (BA 19), left superior frontal cortex (BA 8), right prefrontal cortex (BA 9), and bilateral superiomedial temporal cortex (BA 41 and 42). Individual PET analysis revealed asymmetric representation within sensorimotor cortex in six of eight subjects, four lateralizing to right hemisphere and two to left hemisphere. TMS mapping in the five subjects identified condordant interhemisphere asymmetries in the motor representation for pharynx, consistent with the PET findings. We conclude that volitional swallowing recruits multiple cerebral regions, in particular sensorimotor cortex, insula, temporopolar cortex, cerebellum, and brain stem, the sensorimotor cortex displaying strong degrees of interhemispheric asymmetry, further substantiated with TMS. Such findings may help explain the variable nature of swallowing disorders after stroke and other focal lesions to the cerebral cortex.     

Visual attention deficits in Alzheimer's disease: an fMRI study

Cognitive and neuroscience studies indicate that attentional operations are impaired in Alzheimer's disease (AD). Our goal was to define the anatomical areas of activation associated with visual attention processing and to define deficits or changes that may occur in AD patients compared with control group. Thirteen AD patients and 13 age- and education-matched normal controls were tested in two visual search tasks (one was a conjunction task, where feature binding is required. The other was a subset task, where group stimuli is needed without feature binding) using fMRI techniques. After stereotactical normalization, voxel-by-voxel t statistics was used to compare activated brain areas between patients and control subjects. Our findings suggest that both search tasks are controlled by partially overlapping cerebral networks, including parietal, frontal and occipital-temporal cortical regions and primary visual cortex. The AD patient group showed less activation in both parietal lobes and the left frontal regions, while increased activation was found in the right frontal lobes and the right occipito-temporal cortical regions with the conjunction task. In the subset task, decreased activation in AD patients was seen in the left parietal lobe and bilateral frontal lobes, while increased activation was seen in both medial temporal lobes. In addition, for the comparison between tasks, The difference is very small for AD patients. Control group showed a higher amplitude in the right prefrontal region, temporal cortical regions and parietal lobe. These results indicate that attention deficits in AD patients may be attributed to both binding problem and grouping inefficiency.     

Distributed cortical networks for focused auditory attention and distraction

We used behavioral measures and functional magnetic resonance imaging (fMRI) to study the effects of parametrically varied task-irrelevant pitch changes in attended sounds on loudness-discrimination performance and brain activity in cortical surface maps. Ten subjects discriminated tone loudness in sequences that also included infrequent task-irrelevant pitch changes. Consistent with results of previous studies, the task-irrelevant pitch changes impaired performance in the loudness discrimination task. Auditory stimulation, attention-enhanced processing of sounds and motor responding during the loudness discrimination task activated supratemporal (auditory cortex) and inferior parietal areas bilaterally and left-hemisphere (contralateral to the hand used for responding) motor areas. Large pitch changes were associated with right hemisphere supratemporal activations as well as widespread bilateral activations in the frontal lobe and along the intraparietal sulcus. Loudness discrimination and distracting pitch changes activated common areas in the right supratemporal gyrus, left medial frontal cortex, left precentral gyrus, and left inferior parietal cortex.     

Cerebral cortical processing of swallowing in older adults

While brain-imaging studies in young adults have implicated multiple cortical regions in swallowing, investigations in older subjects are lacking. This study examined the neural representations of voluntary saliva swallowing and water swallowing in older adults. Nine healthy females were examined with event-related functional magnetic resonance imaging (fMRI) while laryngeal swallow-related movements were recorded. Swallowing in the older adults, like young adults, activated multiple cortical regions, most prominently the lateral pericentral, perisylvian, and anterior cingulate cortex. Activation of the postcentral gyrus was lateralized to the left hemisphere for saliva and water swallowing, consistent with our findings in young female subjects. Comparison of saliva and water swallowing revealed a fourfold increase in the brain volume activated by the water swallow compared to the saliva swallow, particularly within the right premotor and prefrontal cortex. This task-specific activation pattern may represent a compensatory response to the demands of the water swallow in the face of age-related diminution of oral sensorimotor function.     

Parallel cortical networks for volitional control of swallowing in humans

A number of studies have demonstrated the involvement of parallel networks in the control of voluntary sequential motor procedures. We sought to determine whether a parallel network organization may be found for complex, sequentially based motor systems that are the product of both voluntary and automatic control processes. Specifically, we sought to determine whether the cortical organizational scheme for voluntary repetitive swallowing in adult humans is characterized by a hierarchical dual-projection model or by modules organized into parallel systems. We utilized functional magnetic resonance imaging (fMRI) to investigate cortical function during normal swallowing tasks in eight healthy human adults. Subjects performed both dry (saliva) and bolus (3 ml/bolus of water) swallows. Activation during swallowing tasks localized to sensorimotor areas (M1, S1, and SMA), S2, premotor cortex, posterior parietal cortex, cingulate gyrus, inferior frontal gyrus, the cerebellum, the insular cortex, auditory cortex, corpus callosum, and the basal ganglia and thalamus. Principal components analysis (PCA) of these regions revealed five functional clusters or modules: (1) sensorimotor areas and cingulate gyrus; (2) inferior frontal gyrus, S2, corpus callosum, basal ganglia and thalamus; (3) premotor cortex and posterior parietal cortex; (4) cerebellum; and (5) insula. Analysis of the functional relationship between these areas demonstrated two parallel loops defined by connections to either the cerebellum or insula and connected through the sensorimotor-cingulate module. Path analysis was performed to test the hypothesis of modules organized into parallel loops versus a hierarchical dual-projection model consisting of two separate, singular hierarchical serial pathways from the sensorimotor cortex or insula to the thalamus. These results support the model of modules organized into parallel loops (P=0.8), but not the hierarchical dual-projection model (P<0.0001). Organization of the control of voluntary repetitive swallowing into two parallel systems may confer the ability to effectively coordinate and integrate this highly complex sequentially based motor behavior. Electronic Publication     

Changes in cortical activation in craniomandibular disorders during splint therapy - a single subject fMRI study

There is some controversial discussion within the therapy of craniomandibular disorders (CMDs) about the mode of action of occlusal splints. Here we present a case report on one CMD-patient measuring cerebral activation changes with functional magnetic resonance imaging (fMRI) before and after therapy with a stabilization splint. Wearing the Michigan splint for 11 nights and partially days resulted in substantial pain relief and changes in occlusal movement performance. Cerebral activation during occlusion was decreased after therapy (PRE-POST) in bilateral sensorimotor regions but also additional areas such as left posterior insula, right superior temporal cortex and bilateral occipital lobe. During the first usage of the splint in the scanner (PRE) increased activation in the left dorsolateral prefrontal lobe (BA 9) was observed. After splint training occlusion with the splint compared to without a splint increasingly involved the left superior parietal lobe (BA 7, POST). Whereas BA 9 might be associated with increasing working memory load due to the manipulation with an unusual object, the BA 7 activation in the POST session might document increased sensorimotor interaction after getting used to the splint. Our findings indicate that wearing an occlusion splint triggers activation in parietal sensorimotor integration areas, also observed after long periods of sensorimotor training. These additional recourses might improve coordination and physiological handling of the masticatory system.     

Central nervous system control of the laryngeal muscles in humans

Laryngeal muscle control may vary for different functions such as: voice for speech communication, emotional expression during laughter and cry, breathing, swallowing, and cough. This review discusses the control of the human laryngeal muscles for some of these different functions. Sensori-motor aspects of laryngeal control have been studied by eliciting various laryngeal reflexes. The role of audition in learning and monitoring ongoing voice production for speech is well known; while the role of somatosensory feedback is less well understood. Reflexive control systems involving central pattern generators may contribute to swallowing, breathing and cough with greater cortical control during volitional tasks such as voice production for speech. Volitional control is much less well understood for each of these functions and likely involves the integration of cortical and subcortical circuits. The new frontier is the study of the central control of the laryngeal musculature for voice, swallowing and breathing and how volitional and reflexive control systems may interact in humans.