Changes in functional connectivity of ventral anterior cingulate cortex in heroin abusers

Background Previous studies with animal experiments, autopsy, structural magnetic resonance imaging （MRI） and task-related functional MRI （fMRI） have confirmed that brain functional connectivity in addicts has become impaired. The goal of this study was to investigate the alteration of resting-state functional connectivity of the ventral anterior cingulate cortex （vACC） in the heroin abusers＇ brain. Methods Fifteen heroin abusers and fifteen matched healthy volunteers were studied using vACC as the region-of interest （ROI） seed. A 3.0 T scanner with a standard head coil was the imagining apparatus. T2＊-weighted gradient-echo planar imaging （GRE-EPI） was the scanning protocol. A ROI seed based correlation analysis used a SPM5 software package as the tool for all images processing. Results This study showed a functional connection to the insula vACC in heroin abusers. Compared with controls, heroin users showed decreased functional connectivity between the nucleus accumbens （NAc） and vACC, between the parahippocampala gyrus/amgdala （PHC/amygdala） and vACC, between the thalamus and vACC, and between the posterior cingulated cortex/precuneus （PCC/pC） and vACC. Conclusion The altered resting-state functional connectivity to the vACC suggests the neural circuitry on which the addictive drug has an affect and reflects the dysfunction of the addictive brain.     

海洛因依赖者低频振幅算法功能性磁共振研究

目的 采用静息态功能性磁共振成像的低频振幅技术,探讨海洛因依赖者脑活动的神经机制及其意义.方法 运用功能性磁共振技术观察海洛因成瘾者的脑血氧水平依赖信号的改变;对15例海洛因海洛因依赖者和15名正常志愿者进行静息态数据采集,然后运用低频振幅算法对采集后的静息态数据进行分析,得到每个被试的低频振幅统计图,最后对两组进行双样本t检验,以P＜0.05,t＞2.060为阈值显示海洛因依赖者相对于正常人ALFF增高和减弱的区域.结果 海洛因依赖组和正常对照组相比ALFF减弱的脑区分布在右颞叶(45,-30,-21)、左侧海马(-36,-33,-6)、右侧丘脑(24,-12,27)、左侧后扣带回(-15,-54,24)、右侧顶叶及楔前叶(21,-51,36)、右侧顶下小叶(45,-42,63)、右侧额叶背外侧面(21,-48,78);而海洛因依赖组在左侧前额叶(0,39,72)ALFF明显高于对照组.结论 海洛因依赖者静息状态下表现出异常的脑功能活动方式,这些异常的活动可能与海洛因依赖的产生、维持及戒断后复吸密切相关.

Abstract：

Objective To study the changes of amplitude of low-frequency fluctuation (ALFF) of the resting state fMRI in heroin abuser (HD), and discussed its underlying neurophysiological mechanism.Methods The resting state fMRI data of 15 heroin abusers and 15 normal volunteers were analyzed by ALFF.The amplitude of the blood oxygenation level dependent activation of the resting state brain was investigated.The brain structures showing increased and decreased ALFF in TLE patients were demonstrated by comparing to normal subjects with 2-sample t -test with threshold of P＜0.05.Results Compared with normal subjects,the regions showing decreased ALFF in HD patients were distributed in right temporal lobe(45, - 30, -21 ) ,left hippocampus( - 36,- 33, - 6), right thalamus ( 24, - 12,27 ), left posterior cingulum gyrus ( - 15, - 54,24 ), right parietal lobe /precuneus ( 21, - 51,36 ), right inferior parietal lobule ( 21, - 48,78 ) and dorsal lateral aspect of the right frontal lobe(21, - 48,78) ,while ALLF of left(45, - 42,63 ) lateral frontal cortex(0 ,39,72) in HD patients was significantly higher.Conclusion HD shows abnormal brain functional organization in resting state, which may play an important role in the production, maintenance and relapse after withdrawal of heroin abuse.     

抑郁症首发未治疗患者情绪调控环路脑功能网络的静息态功能磁共振研究

Background  Reports on mood regulating circuit (MRC) indicated different activities between depressed patients and healthy controls. The functional networks based on MRC have not been described in major depression disorder (MDD). Both the anterior cingulate cortex (ACC) and thalamus are all the key regions of MRC. This study was to investigate the two functional networks related to ACC and thalamus in MDD.

Methods  Sixteen patients with MDD on first episode which never got any medication and sixteen matched health controls were scanned by 3.0 T functional magnetic resonance imaging (fMRI) during resting-state. The pregenual anterior cingulate cortex (pgACC) was used as seed region to construct the functional network by cortex section. The thalamus was used as seed region to construct the functional network by limbic section. Paired-t tests between-groups were performed for the seed-target correlations based on the individual fisher z-transformed correlation maps by SPM2.

Results  Depressed subjects exhibited significantly great functional connectivity (FC) between pgACC and the parahippocampus gyrus in one cluster (size 923) including left parahippocampus gyrus (–21, –49,7), left parietal lobe (–3, –46, 52) and left frontal lobe (–27, –46, 28). The one cluster (size 962) of increased FC on thalamus network overlapped the precuneus near to right parietal lobe (9, –52,46) and right cingulate gyrus (15, –43, 43) in health controls.

Conclusions  Abnormal functional networks exist in earlier manifestation of MDD related to MRC by both cortex and limbic sections. The increased functional connectivity of pgACC and decreased functional connectivity of thalamus is mainly involved in bias mood processing and cognition.

     

Decreased regional homogeneity in major depression as revealed by resting-state functional magnetic resonance imaging

Backgroud  Functional imaging studies indicate abnormal activities in cortico-limbic network in depression during either task or resting state. The present work was to explore the abnormal spontaneous activity shown with regional homogeneity (ReHo) in depression by resting-state functional magnetic resonance imaging (fMRI).

Methods  Using fMRI, the differences of regional brain activity were measured in resting state in depressed vs. healthy participants. Sixteen participants firstly diagnosed with major depressive disorder and 16 controls were scanned during resting state. A novel method based on ReHo was used to detect spontaneous hemodynamic responses across the whole brain.

Results  ReHo in the left thalamus, left temporal lobe, left cerebellar posterior lobe, and the bilateral occipital lobe was found to be significantly decreased in depression compared to healthy controls in resting state of depression.

Conclusions  Abnormal spontaneous activity exists in the left thalamus, left temporal lobe, left cerebellar posterior lobe, and the bilateral occipital lobe. And the ReHo may be a potential reference in understanding the distinct brain activity in resting state of depression.

     

Spontaneous brain activity in chronic smokers revealed by fractional amplitude of low frequency fluctuation analysis: a resting state functional magnetic resonance imaging study

Background Nicotine is primarily rsponsible for the highly addictive properties of cigarettes. Similar to other substances, nicotine dependence is related to many important brain regions, particular in mesolimbic reward circuit. This study was to further reveal the alteration of brain function activity dudng resting state in chronic smokers by fractional amplitude of low frequency fluctuation （fALFF） based on functional magnetic resonance imaging （fMRI）, in order to provide the evidence of neurobiological mechanism of smoking. Methods This case control study involved twenty healthy smokers and nineteen healthy nonsmokers recruited by advertisement. Sociodemographic, smoking related characteristics and fMRI images were collected and the data analyzed. Results Compared with nonsmokers, smokers showed fALFF increased significantly in the left middle occipital gyrus, left limbic lobe and left cerebellum posterior lobe but decreases in the right middle frontal gyrus, right superior temporal gyrus, right extra nuclear, left postcentral gyrus and left cerebellum anterior lobe （cluster size 〉100 voxels）. Compared with light smokers （pack years 〈20）, heavy smokers （pack years 〉20） showed fALFF increased significantly in the right superior temporal gyrus, right precentral gyrus, and right occipital Iobe/cuneus but decreased in the right/left limbic Iobe/cingulate gyrus, right/left frontal lobe/sub gyral, right/left cerebellum posterior lobe （cluster size 〉50 voxels）. Compared with nonsevere nicotine dependent smokers （FagerstrSm test for nicotine dependence, score 〈6）, severe nicotine dependent smokers （score 〉6） showed fALFF increased significantly in the right/left middle frontal gyrus, right superior frontal gyrus and left inferior parietal Iobule but decreased in the left limbic Iobe/cingulate gyrus （cluster size 〉25 voxels）. Conclusions In smokers during rest, the activity of addiction related regions were increased and the activity of smoking feeling, memory, related regions were also changed. The resting state activity changes in many regions were associated with the cumulative amount of nicotine intake and the severity of nicotine dependence.     

慢性腰背痛患者前扣带回功能连接的fMRI研究

目的 利用功能磁共振成像技术(function magnetic resonance imaging,fMRI),探讨慢性腰背痛患者在静息状态下脑内功能连接情况。方法 对15例慢性腰背痛患者在静息状态下进行MR扫描,选择双侧前扣带回后部(posterior anterior cingulated cortex,p ACC)作为种子点,分析其脑内功能连接情况,采用两样本t检验方法与年龄分布相同的健康对照组进行比较。结果 与正常对照组相比,慢性腰背痛患者在静息状态下多个脑区与p ACC的功能连接存在异常:双侧距状回及邻近后扣带回、前额叶中内侧及邻近前扣带回、左侧中央前回及邻近中央后回、右侧扣带回中后部的功能连接减弱;右侧岛叶后部、左侧额下回(眶部、三角部)及邻近左侧岛叶前部、左侧颞上回的功能连接增强。结论 静息状态下慢性腰背痛患者多个脑区与p ACC的功能连接存在异常。     

两组功能相似穴位具有相同的神经表征：一项功能性核磁共振成像研究

Objective： To investigate whether the neural representations underlying alternating two acupoint combinations （ACs） are the same or not. Methods： In this functional magnetic resonance imaging study, two sets of analgesia ACs were utilized, including Waiguan （TE5） and Qiuxu （GB40） for Group A, and Neiguan （PC6） and Taichong （LR3） for Group B, which are the most commonly adopted in clinical treatment. Each group had 20 healthy subjects. An experinlental design was proposed, which consisted of a pre-needling resting phase, a needling phase and a post-needling resting phase. This paradigm optimally mimics the clinical protocol as well as focuses on both the stimulation and the resting periods. The results were subjected to general linear model analysis, conjunction analysis and the functional connectivity analysis. Results： The rostral anterior cingulated cortex was engaged in the initiative period of the acupuncture effect in both groups, and it was chosen as the seed region for the functional connectivity analysis for the following resting period. The results showed that several shared brain regions were involved in both groups, in particular the insula, amygdala and hypothalamus. Moreover, significant differences were located at the posterior cingulated cortex as revealed by a two sample t-test （P〈0.05, corrected）. Other regions showed no significant differences. This finding was further supported by the spatial correlation analysis that the two groups were significantly correlated （r=0.51, P〈0.01）. Conclusion： This preliminary research helps us understand the neurophysiological mechanisms of acupuncture when following clinical guidelines on ACs, as well as provides an important opportunity to develop better treatment strategies for reducing, or even preventing pain.     

Uhwang Chungsim Won Decreases Blood Oxygen Level-Dependent fMRI Signal Response to A Motor Stimulation Task

Objectives:To evaluate the effect of Uhwang Chungsim Won[UC,Niuhuang Qingxin Pill(牛黄清心丸)]on the blood oxygen level-dependent(BOLD) functional magnetic resonance imaging(fMRI) signal response to a motor stimulation task using a hand grasping paradigm.Methods:Ten healthy right-handed male volunteers were recruited.Their BOLD fMRI signal characteristics during hand grasping were determined before and 1 h after consuming UC.Results:With the administration of UC,BOLD responses to the right hand motor task showed a decrease in both hemispheres including the right cerebellar culmen,right and left medial frontal gyrus,right parahippocampal gyrus,right and left sublobar insula,right and left posterior cinguiate,left precuneus,and right precentral gyrus.Decreased BOLD responses to the left hand motor task were shown in the right lingual gyrus,right cerebellar culmen,left superior temporal gyrus,right and left middle frontal gyrus,and right precentral gyrus after UC administration.Increased BOLD responses to the left hand motor task were shown in the left and right posterior cinguiate,while there was no increased response to the right hand motor task after UC administration.Conclusions:UC administration significantly decreased fMRI BOLD signal responses to hand grasping in most of the brain areas including the primary motor cortex,but it is not clear whether these decreased responses were caused by a decrease in neuronal activities or by an increase in cerebral blood flow due to the cerebral vasodilatory effects of UC.Further studies using positron emission tomography or single photon emission computed tomography are needed to fully elucidate these findings.     

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.     

Abnormal intrinsic brain activity in amnestic mild cognitive impairment revealed by amplitude of low-frequency fluctuation: a resting-state functional magnetic resonance imaging study

Background Previous studies have shown that brain functional activity in the resting state is impaired in Alzheimer’s disease (AD) patients. However, alterations in intrinsic brain activity patterns in mild cognitive impairment (MCI) patients are poorly understood. This study aimed to explore the differences in regional intrinsic activities throughout the whole brain between aMCI patients and controls.

Methods In the present study, resting-state functional magnetic resonance imaging (fMRI) was performed on 18 amnestic MCI (aMCI) patients, 18 mild AD patients and 20 healthy elderly subjects. And amplitude of low-frequency fluctuation (ALFF) method was used.

Results Compared with healthy elderly subjects, aMCI patients showed decreased ALFF in the right hippocampus and parahippocampal cortex, left lateral temporal cortex, and right ventral medial prefrontal cortex (vMPFC) and increased ALFF in the left temporal-parietal junction (TPJ) and inferior parietal lobule (IPL). Mild AD patients showed decreased ALFF in the left TPJ, posterior IPL (pIPL), and dorsolateral prefrontal cortex compared with aMCI patients. Mild AD patients also had decreased ALFF in the right posterior cingulate cortex, right vMPFC and bilateral dorsal MPFC (dMPFC) compared with healthy elderly subjects.

Conclusions Decreased intrinsic activities in brain regions closely related to episodic memory were found in aMCI and AD patients. Increased TPJ and IPL activity may indicate compensatory mechanisms for loss of memory function in aMCI patients. These findings suggest that the fMRI based on ALFF analysis may provide a useful tool in the study of aMCI patients.

     

应用基于体素的形态测量学方法研究颞叶癫痫患者脑白质体积变化

目的运用基于体素的形态测量学(VBM)技术对颞叶癫痫(TLE)患者全脑白质体积进行分析,并探讨颞叶癫痫患者大脑内部的结构改变及其规律。方法收集22例颞叶癫痫患者(其中左侧颞叶癫痫组11例,右侧颞叶癫痫组11例)和15例性别、年龄匹配的正常健康志愿者,使用磁化准备快速梯度回波序列(MPRAGE)进行全脑结构像扫描,采用基于体素的形态学测量学(VBM)方法对T1WI 3D图像进行统计分析,计算每一组全脑白质的体积(以体素表示),提取部分脑区体积以比较组间差异,另外分别将左TLE组、右TLE组与对照组进行组间检验,以得出左TLE组与右TLE组白质体积有差异的脑区。结果 1、左TLE组较对照组脑白质体积降低的脑区有:左侧海马旁回、右侧颞中回、左侧额上回、左侧丘脑、右侧岛叶、左侧顶下小叶、左侧顶上小叶;2、右TLE组较对照组脑白质体积降低的脑区有:右侧颞下回、左侧舌回、左侧枕中回、右侧额上回、左侧中央前回、左侧颞上回、右侧楔前叶、右侧中央后回、左侧顶下小叶。结论颞叶癫痫患者存在多个脑区白质结构异常,通过采用基于体素的形态测量学技术可以反映脑白质体积的变化。     

强迫性障碍患者的脑功能活动特点及丘脑与全脑功能连接分析

目的 比较静息状态下强迫性障碍患者脑功能活动与健康对照的差异,并分析患者双侧丘脑与全脑功能连接模式的特点。 方法 按照ICD-10中强迫性障碍的诊断标准,选取26例强迫性障碍患者(OCD组)和性别、年龄、受教育程度相匹配的25例健康志愿者(HC组),分别进行Y-BOCS、HAMA、HAMD量表测验和大脑功能磁共振扫描。在全脑体素水平上进行ReHo分析,筛选出2组间ReHo值有差异的脑区,分别以左右两侧丘脑作为种子点进行全脑功能连接分析。 结果 将统计阈值设置为P<0.005,激活体素>1 512 mm3,Alphasim校正(P<0.005),结果显示OCD组与HC组ReHo值有差异的脑区:左侧丘脑、右侧丘脑、右侧中央旁小叶、右侧中央后回、左侧角回。将左侧丘脑作为种子点的脑功能连接分析,OCD组较HC组功能连接减弱的脑区:双侧丘脑、左侧额中回、右侧海马、右侧尾状核;OCD组较HC组功能连接增强的脑区:双侧中央前回、左侧顶叶、双侧颞叶、双侧中央后回、双侧距状回、双侧舌回、双侧楔前叶、双侧楔叶、双侧小脑、右侧梭状回、双侧中央旁小叶。将右侧丘脑作为种子点的脑功能连接分析,OCD组较HC组功能连接减弱的脑区:左侧额中回、右侧额上回、双侧丘脑、双侧前扣带回、双侧中扣带回、右侧缘回;OCD组较HC组功能连接增强的脑区:双侧颞叶、双侧枕叶、双侧小脑、双侧楔叶、左侧梭状回、双侧舌回、双侧距状回。 结论 强迫性障碍患者多个脑区功能活动异常,边缘CSTC环路功能连接减弱,丘脑与大脑中后部出现代偿性功能连接增强。      

脑震荡后认知功能障碍患者内侧前额叶皮质功能连接变化的fMRI研究

目的 利用静息态功能磁共振成像探讨脑震荡综合征(PCS)患者内侧前额叶皮质功能连接变化及其意义. 方法 PCS患者27例,同期招募27例健康对照者,采集并处理静息态f-MRI数据,分别以左右侧内侧前额叶作为感兴趣区与全脑进行功能连接计算,得出PCS患者内侧前额叶与全脑功能连接有改变的脑区.结果 左侧内侧前额叶与双侧豆状核、左侧脑岛、双侧额下回眶部、右侧颞中回、额上回、额中回、额下回功能连接减弱,与左侧梭状回、左侧颞上回、左侧颞中回及左侧顶上小叶功能连接增强;右侧内侧前额叶与双侧顶下小叶、右侧距状回、左侧中央前回及中央后回功能连接减弱,与左侧海马旁回及右侧颞下回功能连接增强(P<0.05).结论 静息状态下PCS患者内侧前额叶的功能连接存在异常,可能是导致PCS患者认知障碍的原因之一.     

海洛因成瘾者后扣带回皮层在静息态及毒品线索诱导任务中的功能异常

Background Previous animal and neuroimaging studies have demonstrated that brain function in heroin addicted users is impaired.However,the posterior cingulate cortex (PCC) has not received much attenti...     

基于体素的形态测量学方法分析颞叶癫痫患者脑灰质体积变化

目的采用基于体素的形态测量学方法比较颞叶癫痫患者和正常人脑灰质的体积,探讨颞叶癫痫患者脑灰质体积的变化。方法收集22例经手术病例证实的颞叶癫痫患者及15例性别、年龄相匹配的健康志愿者,分别行全脑三维结构像扫描,采用基于体素的形态学测量学(VBM)方法分析病例组及对照组的数据,计算和比较两组脑灰质的体积。结果与对照组相比,左侧颞叶癫痫患者的右侧小脑前叶、左侧颞中回、左侧颞下回、左侧枕中回、左侧额下回、右侧额下回、右侧颞中回、左侧海马、左侧额上回、右侧尾状叶、右侧额中回、左侧中央后回、右侧中央前回灰质体积减小(P均0.05);右侧颞叶癫痫患者的右侧颞下回、右侧颞中回、左侧舌回、左侧枕下回、左侧颞下回、左侧海马旁回、右侧丘脑、左侧枕上回、左侧颞中回、右侧额上回、左侧中央前回、左侧中央后回、右侧中央前回灰质体积减小(P均0.05)。结论颞叶癫痫患者多个脑区脑灰质体积降低,通过采用基于体素的形态测量学技术可以反映脑灰质体积的变化。     

未治疗惊恐障碍患者脑结构和脑功能的磁共振研究

目的:探讨未治疗惊恐障碍患者的脑结构和脑功能特点.方法:分别对24例惊恐障碍患者和健康对照者依次完成情绪计数Stroop任务的功能磁共振和三维结构磁共振扫描,应用优化的基于体素形态学( voxel-based morphology,VBM)方法分析脑灰质体积.结果:将加工惊恐词汇与中性词汇相比较,惊恐障碍患者组在左侧丘...     

吸烟成瘾者吸烟暗示fMRI研究

目的:观察重度吸烟依赖者在不同生理状态下给予吸烟相关视觉刺激引起脑功能区的不同激活模式。方法:15名右利手受试者完成试验,非吸烟对照组8例,重度吸烟依赖组7例。Block设计,FE-EPI采集,吸烟相关图片作为视觉暗示任务。用SPM2进行数据处理,比较吸烟组与对照组在注射尼古丁前后脑的不同激活模式。结果:①重度吸烟依赖组在尼古丁剥夺12 h后观看吸烟相关图片显示海马后部、丘脑、苍白球等脑区激活,对照组对应脑区激活不明显。两组均有双侧额上回、额中回及扣带回前部激活,激活程度组间差异有显著性(P<0.05)。②重度吸烟依赖组注射尼古丁后观看吸烟相关图片脑激活区明显减少,对照组注射尼古丁出现扣带回前部、海马、岛叶、额上回、额中回激活。③其他脑区的激活:重度吸烟依赖组与对照组均出现小脑、枕叶、颞叶、顶叶激活。结论:重度吸烟依赖组较对照组在吸烟暗示时中脑边缘系统明显激活,证实奖偿环路参与吸烟成瘾;吸烟者和非吸烟者在注射和不注射尼古丁的情况下对吸烟暗示有不同的反应。