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 cogniti...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 Iobule （IPL）. Mild AD patients showed decreased ALFF in the left TPJ, posterior IPL （plPL）, 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.展开更多
Functional magnetic resonance imaging has been widely used to investigate the effects of acupuncture on neural activity. However, most functional magnetic resonance imaging studies have focused on acute changes in bra...Functional magnetic resonance imaging has been widely used to investigate the effects of acupuncture on neural activity. However, most functional magnetic resonance imaging studies have focused on acute changes in brain activation induced by acupuncture. Thus, the time course of the therapeutic effects of acupuncture remains unclear. In this study, 32 patients with amnestic mild cognitive impairment were randomly divided into two groups, where they received either Tiaoshen Yizhi acupuncture or sham acupoint acupuncture. The needles were either twirled at Tiaoshen Yizhi acupoints, including Sishencong（EX-HN1）, Yintang（EX-HN3）, Neiguan（PC6）, Taixi（KI3）, Fenglong（ST40）, and Taichong（LR3）, or at related sham acupoints at a depth of approximately 15 mm, an angle of ± 60°, and a rate of approximately 120 times per minute. Acupuncture was conducted for 4 consecutive weeks, five times per week, on weekdays. Resting-state functional magnetic resonance imaging indicated that connections between cognition-related regions such as the insula, dorsolateral prefrontal cortex, hippocampus, thalamus, inferior parietal lobule, and anterior cingulate cortex increased after acupuncture at Tiaoshen Yizhi acupoints. The insula, dorsolateral prefrontal cortex, and hippocampus acted as central brain hubs. Patients in the Tiaoshen Yizhi group exhibited improved cognitive performance after acupuncture. In the sham acupoint acupuncture group, connections between brain regions were dispersed, and we found no differences in cognitive function following the treatment. These results indicate that acupuncture at Tiaoshen Yizhi acupoints can regulate brain networks by increasing connectivity between cognition-related regions, thereby improving cognitive function in patients with mild cognitive impairment.展开更多
目的通过体素水平静息态功能MRI(resting state functional MRI,rs-fMRI)序列探索脑小血管病相关轻度认知障碍(mild cognitive impairment associated with cerebral small vessel disease,CSVD-MCI)患者早期认知障碍的机制,并分析其与...目的通过体素水平静息态功能MRI(resting state functional MRI,rs-fMRI)序列探索脑小血管病相关轻度认知障碍(mild cognitive impairment associated with cerebral small vessel disease,CSVD-MCI)患者早期认知障碍的机制,并分析其与临床神经心理学指标的相关性。材料与方法筛选临床及常规MRI检查符合CSVD-MCI诊断标准的受试者21例,并挑选与其年龄、性别及受教育年限相匹配的健康对照(health control,HC)20例,所有被试都接受rs-fMRI检查,计算全脑度中心度(degree centrality,DC)值,将两组DC值差异显著团块的峰值蒙特利尔神经病学研究所(Montreal Neurological Institute,MNI)坐标作为种子点,与全脑其他体素进行功能连接(functional connection,FC)分析,两组脑功能存在差异脑区的DC及FC值与蒙特利尔认知评估量表(Montreal Cognitive Assessment,MoCA)评分进行相关性分析,并进一步分析CSVD总负荷评分与MoCA评分,以及CSVD总负荷评分与各认知域评分的相关性。结果与HC组相比,CSVD-MCI组左侧内侧额上回/左侧前扣带回、左侧角回/左侧缘上回、右侧内侧额上回/右侧额中回、左侧小脑及右侧小脑DC值减低,左侧前扣带回与左侧颞中下回、双侧楔前叶、双侧中扣带回FC值减低。白质高信号评分、CSVD总负荷评分与MoCA评分呈显著负相关(r_(s)=−0.461,P=0.036;r_(s)=−0.458,P=0.037);CSVD总负荷评分与视空间和执行功能评分呈负相关(r_(s)=−0.473,P=0.030),与其他认知域评分无显著相关性。CSVD-MCI组左侧前扣带回-右侧楔前叶FC值与MoCA评分呈显著正相关(r=0.565,P=0.018)。结论常规MRI可以显示CSVD特征性影像学病灶,rs-fMRI序列可以早期发现DC及FC减低脑区,CSVD评分及DC、FC值与临床神经心理学评分呈明显相关,可作为CSVD-MCI患者的潜在影像学标志物,揭示其认知功能减退的潜在机制。展开更多
目的探讨体素镜像同伦连接(voxel-mirrored homotopic connectivity,VMHC)与局部一致性(regional homogeneity,ReHo)在评价经颅直流电刺激(transcranial direct current stimulation,tDCS)改善脑卒中后认知障碍中的应用价值。材料与方...目的探讨体素镜像同伦连接(voxel-mirrored homotopic connectivity,VMHC)与局部一致性(regional homogeneity,ReHo)在评价经颅直流电刺激(transcranial direct current stimulation,tDCS)改善脑卒中后认知障碍中的应用价值。材料与方法前瞻性纳入47名脑卒中后认知障碍(post-stroke cognitive impairment,PSCI)患者,随机分配到tDCS组与假刺激组,其中tDCS组23人,假刺激组24人,应用Mann-Whitney U检验比较两组患者在基线期与15天tDCS或假刺激治疗后认知量表评分变化值的差异,应用配对t检验比较两组患者在基线期与15天tDCS或假刺激治疗后VMHC与ReHo指标的差异,并提取差异脑区的VMHC与ReHo值与治疗前后认知量表评分的变化值进行相关性分析。结果tDCS组与假刺激组在治疗后的简易智能精神状态量表(Mini-Mental State Examination,MMSE)与蒙特利尔认知评估量表(Montreal Cognitive Assessment,MoCA)评分均优于治疗前,但tDCS组具有更好的治疗效果,治疗后相较于治疗前MMSE与MoCA量表评分改善值更大,差异具有统计学意义(P<0.05);VMHC指标结果:tDCS组患者在治疗后,双侧岛叶、楔前叶的VMHC值升高(P<0.05,FDR校正),假刺激组患者在治疗后,在双侧枕上回的VMHC值升高(P<0.05,FDR校正);ReHo指标结果:tDCS组患者在治疗后,前扣带回和顶下缘角回的ReHo值升高(P<0.05,FDR校正),假刺激组患者在治疗后相较于治疗前,未见明显差异脑区;相关性分析:tDCS组患者在治疗后,双侧楔前叶VMHC增加的值与MMSE、MoCA量表评分的变化值呈现正相关,MMSE(r=0.47,P=0.02);MoCA(r=0.43,P=0.04);其他差异脑区与MMSE与MoCA量表评分变化值无明显相关性。结论tDCS联合常规康复治疗对PSCI患者的认知康复效果优于仅进行常规康复治疗手段,应用VMHC与ReHo发现tDCS的治疗机制可能与改善默认模式网络(default mode network,DMN)与突显网络(salience network,SN)中部分脑区在双侧大脑半球之间的功能连接与自发活动有关。展开更多
Numerous studies have shown abnormal brain functional connectivity in individuals with Alzheimer’s disease(AD)or amnestic mild cognitive impairment(aMCI).However,most studies examined traditional resting state functi...Numerous studies have shown abnormal brain functional connectivity in individuals with Alzheimer’s disease(AD)or amnestic mild cognitive impairment(aMCI).However,most studies examined traditional resting state functional connections,ignoring the instantaneous connection mode of the whole brain.In this case-control study,we used a new method called dynamic functional connectivity(DFC)to look for abnormalities in patients with AD and aMCI.We calculated dynamic functional connectivity strength from functional magnetic resonance imaging data for each participant,and then used a support vector machine to classify AD patients and normal controls.Finally,we highlighted brain regions and brain networks that made the largest contributions to the classification.We found differences in dynamic function connectivity strength in the left precuneus,default mode network,and dorsal attention network among normal controls,aMCI patients,and AD patients.These abnormalities are potential imaging markers for the early diagnosis of AD.展开更多
Background:Resting-state functional magnetic resonance imaging studies using a regional homogeneity(ReHo)method have reported that amnestic mild cognitive impairment(aMCI)was associated with abnormalities in local fun...Background:Resting-state functional magnetic resonance imaging studies using a regional homogeneity(ReHo)method have reported that amnestic mild cognitive impairment(aMCI)was associated with abnormalities in local functional connectivity.However,their results were not conclusive.Methods:Seed-based d Mapping was used to conduct a coordinate-based meta-analysis to identify consistent ReHo alterations in aMCI.Results:We identified 10 studies with 11 datasets suitable for inclusion,including 378 patients with aMCI and 435 healthy controls.This meta-analysis identified significant ReHo alterations in patients with aMCI relative to healthy controls,mainly within the default mode network(DMN)(bilateral posterior cingulate cortex[PCC],right angular gyrus,bilateral middle temporal gyri,and left parahippocampal gyrus/hippocampus),executive control network(right superior parietal lobule and dorsolateral prefrontal cortex),visual network(right lingual gyrus and left middle occipital gyrus),and sensorimotor network(right paracentral lobule/supplementary motor area,right postcentral gyrus and left posterior insula).Significant heterogeneity of ReHo alterations in the bilateral PCC,left parahippocampal gyrus/hippocampus,and right superior parietal lobule/angular gyrus was observed.Exploratory meta-regression analyses indicated that general cognitive function,gender distribution,age,and education level partially contributed to this heterogeneity.Conclusions:This study provides provisional evidence that aMCI is associated with abnormal ReHo within the DMN,executive control network,visual network,and sensorimotor network.These local functional connectivity alterations suggest coexistence of functional deficits and compensation in these networks.These findings contribute to the modeling of brain functional connectomes and to a better understanding of the neural substrates of aMCI.Confounding factors merit much attention and warrant future investigations.展开更多
Impaired structure and function of the hippocampus is a valuable predictor of progression from amnestic mild cognitive impairment（a MCI） to Alzheimer＇s disease（AD）. As a part of the medial temporal lobe memory sy...Impaired structure and function of the hippocampus is a valuable predictor of progression from amnestic mild cognitive impairment（a MCI） to Alzheimer＇s disease（AD）. As a part of the medial temporal lobe memory system,the hippocampus is one of the brain regions affected earliest by AD neuropathology,and shows progressive degeneration as a MCI progresses to AD. Currently,no validated biomarkers can precisely predict the conversion from a MCI to AD. Therefore,there is a great need of sensitive tools for the early detection of AD progression. In this review,we summarize the specifi c structural and functional changes in the hippocampus from recent a MCI studies using neurophysiological and neuroimaging data. We suggest that a combination of advanced multi-modal neuroimaging measures in discovering biomarkers will provide more precise and sensitive measures of hippocampal changes than using only one of them. These will potentially affect early diagnosis and disease-modifying treatments. We propose a new sequential and progressive framework in which the impairment spreads from the integrity of fibers to volume and then to function in hippocampal subregions. Meanwhile,this is likely to be accompanied by progressive impairment of behavioral and neuropsychological performance in the progression of a MCI to AD.展开更多
基金grants from the Natural Science Foundation of China，the Shanghai High Technology Research Program
文摘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 Iobule （IPL）. Mild AD patients showed decreased ALFF in the left TPJ, posterior IPL （plPL）, 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.
基金supported by the National Natural Science Foundation of China,No.81173354a grant from the Science and Technology Plan Project of Guangdong Province of China,No.2013B021800099a grant from the Science and Technology Plan Project of Shenzhen City of China,No.JCYJ20150402152005642
文摘Functional magnetic resonance imaging has been widely used to investigate the effects of acupuncture on neural activity. However, most functional magnetic resonance imaging studies have focused on acute changes in brain activation induced by acupuncture. Thus, the time course of the therapeutic effects of acupuncture remains unclear. In this study, 32 patients with amnestic mild cognitive impairment were randomly divided into two groups, where they received either Tiaoshen Yizhi acupuncture or sham acupoint acupuncture. The needles were either twirled at Tiaoshen Yizhi acupoints, including Sishencong（EX-HN1）, Yintang（EX-HN3）, Neiguan（PC6）, Taixi（KI3）, Fenglong（ST40）, and Taichong（LR3）, or at related sham acupoints at a depth of approximately 15 mm, an angle of ± 60°, and a rate of approximately 120 times per minute. Acupuncture was conducted for 4 consecutive weeks, five times per week, on weekdays. Resting-state functional magnetic resonance imaging indicated that connections between cognition-related regions such as the insula, dorsolateral prefrontal cortex, hippocampus, thalamus, inferior parietal lobule, and anterior cingulate cortex increased after acupuncture at Tiaoshen Yizhi acupoints. The insula, dorsolateral prefrontal cortex, and hippocampus acted as central brain hubs. Patients in the Tiaoshen Yizhi group exhibited improved cognitive performance after acupuncture. In the sham acupoint acupuncture group, connections between brain regions were dispersed, and we found no differences in cognitive function following the treatment. These results indicate that acupuncture at Tiaoshen Yizhi acupoints can regulate brain networks by increasing connectivity between cognition-related regions, thereby improving cognitive function in patients with mild cognitive impairment.
文摘目的采用动脉自旋标记(arterial spin labeling,ASL)、静息态功能磁共振成像(resting-state functional MRI,rs-fMRI)方法,探究认知储备(cognitive reserve,CR)在轻度认知障碍(mlid cognitive impairment,MCI)患者中影响认知功能的神经血管耦合机制。材料与方法本研究前瞻性收集40例MCI患者和26例性别、年龄相匹配的健康对照(healthy controls,HC),所有受试者均在3.0 T MRI机器采集ASL、rs-fMRI图像,所有受试者接受标准化神经心理学评估,包括蒙特利尔认知评估(Montreal Cognitive Assessment,MoCA)、简易精神状态检查(Mini-Mental State Examination,MMSE)、日常生活能力量表(Activity of Daily Living Scale,ADL)、听觉言语学习测验(Auditory Verbal Learning Test,AVLT)(中文版)、言语流畅性测验(Verbal Fluency Test,VFT)。所有受试者接受CR评估,根据两组受试者的教育程度、业余活动时间和工作经历生成认知储备指数问卷(Cognitive Reserve Index questionnaire,CRIq)评分。基于体素水平获取低频振幅(amplitude of low frequency fluctuations,ALFF)、比率低频振幅(fractionalALFF,fALFF)及脑血流量(cerebral blood flow,CBF),计算CBF/ALFF及CBF/fALFF比值,以评估神经血管耦合,并选择CBF/ALFF和CBF/fALFF存在显著组间差异的脑区作为ROI,进一步提取ROI平均值,与各认知功能及认知储备量表间进行相关性分析,以阐明CR、神经血管耦合和认知表现之间的关系。结果MCI组CRIq得分明显低于HC组(89.23±11.03 vs.98.70±12.75);在MCI及HC组中,CRIq得分与MoCA和AVLT得分均呈正相关(r=0.447,P=0.004;r=0.344,P=0.030;r=0.245,P=0.050;r=0.900,P<0.001);与HC相比,MCI患者双侧颞中回CBF/ALFF比值显著升高(双尾检验P<0.005,alphsim校正,团块大小>39),双侧眶部额下回、额中回CBF/ALFF比值显著降低(双尾检验P<0.005,alphsim校正,团块大小>93);双侧颞下回CBF/fALFF比值升高(双尾检验P<0.005,alphsim校正,团块大小>53)。此外,MCI组中,左侧眶部额下回CBF/ALFF比值与CRIq得分及MoCA、AVLT得分均呈负相关(r=-0.417,P=0.007;r=-0.336,P=0.034;r=-0.378,P=0.016)。结论CR较高的人群表现出更好的认知功能水平,且CR越高的MCI患者左侧眶部额下回CBF/ALFF比值越低,即出现了神经血管解耦合现象,表现出更严重的脑病理,但其尚能保持良好的认知功能,提示大脑的神经血管耦合和解耦合可能是CR在MCI患者中影响认知功能的一种潜在的神经机制。
基金supported by the National Natural Science Foundation of China,No.81471120Fund Projects in Technology of the Foundation Strengthening Program of China,No.2019-JCJQ-JJ-151(both to XZ).
文摘Numerous studies have shown abnormal brain functional connectivity in individuals with Alzheimer’s disease(AD)or amnestic mild cognitive impairment(aMCI).However,most studies examined traditional resting state functional connections,ignoring the instantaneous connection mode of the whole brain.In this case-control study,we used a new method called dynamic functional connectivity(DFC)to look for abnormalities in patients with AD and aMCI.We calculated dynamic functional connectivity strength from functional magnetic resonance imaging data for each participant,and then used a support vector machine to classify AD patients and normal controls.Finally,we highlighted brain regions and brain networks that made the largest contributions to the classification.We found differences in dynamic function connectivity strength in the left precuneus,default mode network,and dorsal attention network among normal controls,aMCI patients,and AD patients.These abnormalities are potential imaging markers for the early diagnosis of AD.
基金This work was supported by the National Natural Science Foundation of China(Grant No.81601161)Jiangsu Provincial Commission of Health and Family Planning(Grant No.QNRC2016466).
文摘Background:Resting-state functional magnetic resonance imaging studies using a regional homogeneity(ReHo)method have reported that amnestic mild cognitive impairment(aMCI)was associated with abnormalities in local functional connectivity.However,their results were not conclusive.Methods:Seed-based d Mapping was used to conduct a coordinate-based meta-analysis to identify consistent ReHo alterations in aMCI.Results:We identified 10 studies with 11 datasets suitable for inclusion,including 378 patients with aMCI and 435 healthy controls.This meta-analysis identified significant ReHo alterations in patients with aMCI relative to healthy controls,mainly within the default mode network(DMN)(bilateral posterior cingulate cortex[PCC],right angular gyrus,bilateral middle temporal gyri,and left parahippocampal gyrus/hippocampus),executive control network(right superior parietal lobule and dorsolateral prefrontal cortex),visual network(right lingual gyrus and left middle occipital gyrus),and sensorimotor network(right paracentral lobule/supplementary motor area,right postcentral gyrus and left posterior insula).Significant heterogeneity of ReHo alterations in the bilateral PCC,left parahippocampal gyrus/hippocampus,and right superior parietal lobule/angular gyrus was observed.Exploratory meta-regression analyses indicated that general cognitive function,gender distribution,age,and education level partially contributed to this heterogeneity.Conclusions:This study provides provisional evidence that aMCI is associated with abnormal ReHo within the DMN,executive control network,visual network,and sensorimotor network.These local functional connectivity alterations suggest coexistence of functional deficits and compensation in these networks.These findings contribute to the modeling of brain functional connectomes and to a better understanding of the neural substrates of aMCI.Confounding factors merit much attention and warrant future investigations.
基金supported by the National Natural Science Foundation of China (91332000,81171021,and 91132727)the Key Program for Clinical Medicine and Science and Technology,Jiangsu Provence,China ( BL2013025 and BL2014077)
文摘Impaired structure and function of the hippocampus is a valuable predictor of progression from amnestic mild cognitive impairment（a MCI） to Alzheimer＇s disease（AD）. As a part of the medial temporal lobe memory system,the hippocampus is one of the brain regions affected earliest by AD neuropathology,and shows progressive degeneration as a MCI progresses to AD. Currently,no validated biomarkers can precisely predict the conversion from a MCI to AD. Therefore,there is a great need of sensitive tools for the early detection of AD progression. In this review,we summarize the specifi c structural and functional changes in the hippocampus from recent a MCI studies using neurophysiological and neuroimaging data. We suggest that a combination of advanced multi-modal neuroimaging measures in discovering biomarkers will provide more precise and sensitive measures of hippocampal changes than using only one of them. These will potentially affect early diagnosis and disease-modifying treatments. We propose a new sequential and progressive framework in which the impairment spreads from the integrity of fibers to volume and then to function in hippocampal subregions. Meanwhile,this is likely to be accompanied by progressive impairment of behavioral and neuropsychological performance in the progression of a MCI to AD.
