抑郁症患者脑局部一致性的静息态磁共振研究

目的应用静态功能MR探讨抑郁症患者静息态脑部局部一致性异常。方法对12例重症抑郁症患者及12例年龄、性别及教育程度匹配正常对照组进行静息态功能磁共振成像（resting-fMRI）,所得数据转换后应用局部一致性（ReHo）分析,然后进行基于体素的组间比较,比较两组静息态脑功能的差异（t检验）。结果与健康组比较,抑郁组ReHo减低的脑区有：右脑顶下小叶,右脑海马回,右后扣带回,左枕叶舌回,左小脑前叶,左尾状核,左豆状核,左屏状核。抑郁组ReHo增高的脑区有：右前额叶,左胼胝体,右豆状核-壳核,右屏状核,右小脑后叶小脑扁桃体,右小脑后叶下半月小叶。结论静息态功能磁共振成像可以反映抑郁症患者脑部功能区局部一致性改变。     

短暂性脑缺血脑默认状态网络的功能磁共振研究

目的利用fMRI研究TIA患者脑默认状态网络的变化。方法分别采集16例TIA发作间期患者和16名正常对照组静息态fMRI扫描,以扣带回/楔前叶及腹侧扣带前回/内侧前额叶作为种子点,分析与种子点连通的脑区,研究两组间默认状态网络的变化。结果 TIA组与正常组具有相似脑默认状态网络,TIA组与正常组比较,ROI功能连接减弱的脑区域包括:扣带前回、楔前叶、前额叶及海马等脑区,功能连接增强的区域主要存在小脑及丘脑。结论 TIA患者脑默认状态网络存在异常,扣带回、楔前叶及海马等脑区连通性的减弱反应TIA患者脑DMN失衡,丘脑和小脑的连通性增强,可能是脑TIA局部脑区功能减弱的补偿及保护性反应。     

早发精神分裂症静息态脑功能局部一致性研究

目的通过对早发未用药精神分裂症静息态功能磁共振局部一致性的研究,探索该病存在功能异常的脑区。方法分别对20例早发未用药精神分裂症患者与20名健康对照进行全脑静息态功能磁共振扫描,计算局部一致性值。结果与对照组相比,患者组右侧额中回,右侧额上回ReHo值增高(P<0.05,Al-phaSim校正)。结论静息状态下,早发精神分裂症存在额叶功能的异常,额叶损害可能是精神分裂症较稳定的生物标记物。     

轻微型肝性脑病患者后扣带回与双侧海马间功能连接静息态功能MRI研究

目的 本文采用静息态脑功能MRI影像技术研究轻微型肝性脑病患者局部脑功能后扣带回与双侧海马间功能连接变化情况,为确诊轻微型肝性脑病发病和病理机制提供科学可靠的影像学依据。方法 选取2018年1月至2020年2月我院收治的70例轻微型肝性脑病患者作为病例组,另选取同期来做健康检查的体检者70例作为健康组,采用静息态脑功能MRI影像技术观察病例组患者在静息态下后扣带回与双侧海马间功能连接情况,评估两组患者的数字符号实验(DST)评分和数字连接实验-A(NCT-A)评分。结果 病例组患者的NCT-A评分明显高于健康组,但DST评分明显低于健康组,组间差异有统计学意义(P 0.05)。与健康组相比,病例组右侧海马与后扣带回无FC明显增强的脑区,却存在FC减弱的区域(P 0.05)。右侧海马与后扣带回之间的FC分数与DST评分呈正相关,右侧海马与后扣带回之间的FC分数与NCT-A评分呈负相关,差异有统计学意义(P 0.05)。结论 轻微型肝性脑病患者经过静息态功能MRI检查发现脑部有明显的脑损伤,后扣带回和双侧海马功能连接越强说明患者认知功能损伤越显著。     

单侧突发性感音神经性耳聋患者静息状态默认网络的变化

目的 探索单侧突发性感音神经性耳聋(SSNHL)患者静息状态默认网络的改变.方法 选取16例重度左侧突发性感音神经性耳聋患者(耳聋组)和16例健康志愿者(对照组)进行静息状态脑功能磁共振扫描,通过时程相关方法检测IMRI数据低频波动信号中以后扣带回为种子区的默认网络,并进行组间比较.结果 耳聋组较正常对照组脑功能连接增强的区域为右侧枕中回,耳聋组较正常对照组脑功能连接减弱的区域为右侧额中回.结论 SSNHL患者在静息状态下存在脑默认网络的功能连接异常.     

养血清脑丸对亚健康人群静息态脑功能网络的影响

目的研究养血清脑丸对亚健康人群静息态脑功能网络的影响,初步探讨养血清脑丸改善亚健康状态的神经生理机制。方法收集30例亚健康人群入组,使用养血清脑丸进行3个月的药物干预,分别采集用药前后的静息态功能磁共振数据,采用最小生成树算法进行数据分析,使用配对样本t检验比较脑功能网络的差异。结果用药后,左侧尾状核(t=-2.214,P=0.036)和楔叶(t=-2.214,P=0.036)的度值显著减小,且2个脑区的中间中心度也显著减小(t=-2.214,P=0.036;t=-2.567,P=0.016),其差异具有统计学意义。结论养血清脑丸能使亚健康人群的脑功能网络产生变化,从而改善其亚健康状态。     

氯胺酮成瘾者的静息态脑功能变化

目的:分析氯胺酮成瘾者的静息态脑功能活动变化情况,探索氯胺酮成瘾者的神经学机制。方法:采用静息态功能磁共振(resting-state f MRI)局部一致性(Regional Homogeneity,Re Ho)的方法,分析10名有氯胺酮成瘾者者与10名健康受试者的脑功能活动。结果:与健康受试者相比,氯胺酮成瘾者者双侧顶下缘角回、左侧顶上回、右背外侧额上回、左额中回、左内侧额上回、前扣带回、右侧丘脑、左侧尾状核、右梭状回的Re Ho信号显著升高(P<0.01,Alpha Sim校正,cluster size=18)。结论:证实氯胺酮成瘾者者额叶、顶叶、边缘系统、梭状回和尾状核存在脑功能活动异常。     

低频振幅fMRI在评价精神分裂症患者静息状态下脑功能活动中的应用探讨

目的探讨在评价精神分裂症患者静息状态下脑功能活动中应用低频振幅功能磁共振成像(f MRI)的价值。方法分别选取首发未用药精神分裂症及健康志愿者各40例,将前者记为疾病组,将后者记为健康组。所有受试对象均在静息状态下采用f MRI对其脑功能活性进行测定,对比2组脑功能差异,并采用统计学检验。结果健康组检验结果显示以双侧后扣带回/楔前叶为中心的脑区域ALFF数值显著增高(P<0.05);疾病组检验结果显示上述部分区域的ALFF值显著增高(P<0.05),且前者ALFF值显著增高的区域范围明显比后者广泛。2组双样本t检验显示疾病组ALFF数值增高存在显著性差异的区域有右侧枕叶、右侧胼胝体压部、左侧小脑后叶、左侧楔前叶以及额上回区域(P<0.05),且ALFF数值降低存在显著性差异的区域有左侧楔前叶与左右侧中央后回(P<0.05)。结论采用低频振幅f MRI对精神分裂症患者静息状态下脑功能活动进行检查能为病情评估提供丰富有用的参考信息。     

基于低频振幅算法对斜视性弱视儿童静息态功能磁共振成像的研究

目的:应用低频振幅(ALFF,fALFF)算法分析斜视性弱视儿童的脑功能磁共振图像(fMRI),并与对照组进行对比,观察患者脑活动的变化与异常。方法:在静息态下采集22位斜视性弱视儿童的fMRI和10名健康儿童(对照组),应用t检验对ALFF和fALFF进行组内和组间统计学分析。结果:斜视性弱视儿童患者低于正常对照脑区,主要分布于枕叶、颞叶、小脑后叶、小脑前叶、颞上回、顶叶、额叶、枕中回。结论:基于静息态的fMRI的ALFF和fALFF算法可以反映斜视性弱视儿童视皮层的变化和多脑区神经活动的变化。     

早发性抑郁患者基于低频振幅比特低频振幅下脑区功能活动特征研究

目的利用静息态磁共振技术对早发性抑郁症患者特异性脑区进行定位。方法选择20例我院收治的早发抑郁症患者20例和性别、年龄、受教育年限与患者相匹配的20名健康受试者(对照组),分别给予功能磁共振(fMRI)扫描,分别应用低频振幅(ALFF)、比特低频振幅(fALFF)方法进行基于体素的组间比较,分析其静息态脑功能的差异。结果 (1)在右侧缘上回、左侧额中回、右侧中央沟盖、左侧额上回及右侧眶部额中回的ALFF值强于健康对照组,在舌回、左侧中央前回、左侧小脑10区、左侧颞中回区域的ALFF值弱于健康对照组;(2)在右侧眶部额中回、右侧眶部额下回、右侧缘上回、右侧中央沟盖、左侧眶部额下回、左侧扣带回及右侧枕中回的fALFF强于健康对照组,在左侧中央前回、左侧中央后回、右侧楔叶及右侧梭状回区域的fALFF值弱于健康对照组。结论早发性抑郁患者在前额叶、扣带回、边缘系统等多个区域脑自发活动强于健康受试者;在大脑额叶后部、颞叶前部、枕叶及小脑部分区域等多个区域脑自发活动弱于正常受试者;且ALFF及fALFF算法均存在相对一致性,显示这些特定脑区的脑自发活动异常可能是早发抑郁的神经生物学基础。     

氯胺酮依赖者脑功能活动的局部一致性改变-静息态功能磁共振成像研究

目的:探讨静息状态下氯胺酮依赖者的脑功能活动改变情况。方法:采用血氧水平依赖功能磁共振成像(BOLD-fMRI)技术,分析41例氯胺酮依赖者和44例与之相匹配的无任何物质依赖的健康志愿者静息状态下脑功能活动差异;采用局部一致性(ReHo)分析方法对数据进行处理。结果:与健康志愿者相比,氯胺酮依赖者静息状态下前扣带回BOLD信号ReHo降低(P<0.05,纠正后,cluster水平),额叶中央前回BOLD信号ReHo增强(P<0.05,纠正后,cluster水平)。额叶中央前回的ReHo值增加与总的氯胺酮使用量和对氯胺酮的渴求呈负相关。结论:首次采用ReHo方法分析了氯胺酮依赖者静息状态下脑的BOLD信号变化的脑区。此研究提示,氯胺酮依赖者额叶区功能活动存在异常。     

Acute effects of ∆9-tetrahydrocannabinol (THC) on resting state brain function and their modulation by COMT genotype

Cannabis produces a broad range of acute, dose-dependent psychotropic effects. Only a limited number of neuroimaging studies have mapped these effects by examining the impact of cannabis on resting state brain neurophysiology. Moreover, how genetic variation influences the acute effects of cannabis on resting state brain function is unknown. Here we investigated the acute effects of ∆9-tetrahydrocannabinol (THC), the main psychoactive constituent of cannabis, on resting state brain neurophysiology, and their modulation by catechol-methyl-transferase (COMT) Val158Met genotype. Thirty-nine healthy volunteers participated in a pharmacological MRI study, where we applied Arterial Spin Labelling (ASL) to measure perfusion and functional MRI to assess resting state connectivity. THC increased perfusion in bilateral insula, medial superior frontal cortex, and left middle orbital frontal gyrus. This latter brain area showed significantly decreased connectivity with the precuneus after THC administration. THC effects on perfusion in the left insula were significantly related to subjective changes in perception and relaxation. These findings indicate that THC enhances metabolism and thus neural activity in the salience network. Furthermore, results suggest that recruitment of brain areas within this network is involved in the acute effects of THC. Resting state perfusion was modulated by COMT genotype, indicated by a significant interaction effect between drug and genotype on perfusion in the executive network, with increased perfusion after THC in Val/Met heterozygotes only. This finding suggests that prefrontal dopamine levels are involved in the susceptibility to acute effects of cannabis.     

人脑顶叶在空间记忆认知功能中的作用

目的:通过功能磁共振成像(fMRI)技术研究健康人脑顶叶在处理空间记忆信息时的作用。方法:在对10例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fMRI扫描,实验采用组块设计并采用SPM99软件进行数据分析和脑功能区定位。结果:当统计阈值设为P<0.001时,大脑皮质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:BrodmannArea,布鲁德曼分区,下同),双侧前额上中下回(BA6/9/47),双侧枕叶和枕颞交界处(BA17/18/19/37),右侧海马和右侧扣带回;左侧顶叶的激活强度最强,左侧顶叶与双侧前额叶以及右侧顶叶与左侧前额叶之间的激活强度差异均有统计学意义(P<0.05)。结论:人脑在处理短时空间记忆信息时,顶叶起主导性作用。     

Resting-state functional connectivity abnormalities in limbic and salience networks in social anxiety disorder without comorbidity

The neurobiology of social anxiety disorder (SAD) is not yet fully understood. Structural and functional neuroimaging studies in SAD have identified abnormalities in various brain areas, particularly the amygdala and elements of the salience network. This study is the first to examine resting-state functional brain connectivity in a drug-naive sample of SAD patients without psychiatric comorbidity and healthy controls, using seed regions of interest in bilateral amygdala, in bilateral dorsal anterior cingulate cortex for the salience network, and in bilateral posterior cingulate cortex for the default mode network. Twelve drug-naive SAD patients and pair-wise matched healthy controls, all drawn from the Netherlands Study of Depression and Anxiety sample, underwent resting-state fMRI. Group differences were assessed with voxel-wise gray matter density as nuisance regressor. All results were cluster corrected for multiple comparisons (Z>2.3, p<.05). Relative to control subjects, drug-naive SAD patients demonstrated increased negative right amygdala connectivity with the left middle temporal gyrus, left supramarginal gyrus and left lateral occipital cortex. In the salience network patients showed increased positive bilateral dorsal anterior cingulate connectivity with the left precuneus and left lateral occipital cortex. Default mode network connectivity was not different between groups. These data demonstrate that drug-naive SAD patients without comorbidity show differences in functional connectivity of the amygdala, and of areas involved in self-awareness, some of which have not been implicated in SAD before.     

Decreased regional activity of default-mode network in unaffected siblings of schizophrenia patients at rest

Dysconnectivity hypothesis posits that abnormal resting-state connectivity within the default-mode network (DMN) acts as a key role in schizophrenia. However, little is known about the regional alterations of the DMN in unaffected siblings of schizophrenia patients. Unaffected siblings have a unique advantage in neuroimaging studies independent of clinical and treatment issues that complicate studies on patients themselves. In the present study, we used fractional amplitude of low-frequency fluctuation (fALFF) to investigate regional alterations of the DMN in unaffected siblings of schizophrenia patients at rest. Forty-six unaffected siblings of schizophrenia patients and 50 age-, sex-, and education-matched healthy controls underwent a resting-state functional magnetic resonance imaging (fMRI). The fALFF and independent component analysis (ICA) approaches were used to analyze the data. The unaffected siblings of schizophrenia patients had lower fALFF than the controls in the left inferior temporal gyrus (ITG). No significantly increased fALFF was found in any brain regions in the siblings compared to that in the controls. Further receiver operating characteristic (ROC) curve and support vector machine (SVM) analyses showed that the fALFF values of the left ITG could be utilized to separate the siblings from the controls. Our results first suggest that there is decreased regional activity of the DMN in unaffected siblings of schizophrenia patients, and provide a clue that decreased regional activity of the left ITG could be applied as a candidate biomarker to identify the siblings from the controls.     

多发性硬化（MS）患者静息态视觉网络的脑功能研究

目的评价静息态功能磁共振（rfMRI）方法研究多发性硬化患者视觉网络的价值。方法 34例多发性硬化患者及性别、年龄相匹配的34名健康志愿者均接受静息态功能MRI扫描（采用西门子MAGNRTOM3.0T Trio Tim）,基于Mat-lab2009a平台使用独立成分分析法（independent component analysis,ICA）提取并比较两组视觉网络功能成分的差异,数据统计采用统计参数图（SPM8）软件（双样本t检验）。结果与对照组比较,患者组在左侧楔叶、双侧距状裂、双侧枕上回、左侧楔前叶出现神经元活动增强区。说明患者组静息态视觉网络存在一定的代偿。结论 rfMRI是研究脑功能网络的一种有效办法。     

Cannabis use and progressive cortical thickness loss in areas rich in CB1 receptors during the first five years of schizophrenia

Cerebral grey matter volume reductions are progressive in schizophrenia, with larger grey matter volume decreases associated with cannabis use. It is unknown whether this grey matter loss is globally distributed over the entire brain or more pronounced in specific cortical brain regions. Fifty-one patients with recent-onset schizophrenia and 31 matched healthy subjects were included. For all subjects, magnetic resonance imaging scans were obtained at inclusion and at 5-year follow-up. Nineteen patients (ab-)used cannabis but no other illicit drugs; 32 patients and the healthy comparison subjects did not use any drugs during the 5-year follow-up. At follow-up, clinical outcome was measured. To evaluate the local differences in cortical thickness change over five years between the two groups regression analysis was carried out over the cortical surface. At inclusion cortical thickness did not differ between patients and controls and between cannabis-using and non-using patients. Over the follow-up period we found excessive thinning of the right supplementary motor cortex, inferior frontal cortex, superior temporal gyrus, angular gyrus, occipital and parietal lobe in patients relative to controls after controlling for cannabis use. Patients who used cannabis showed additional thinning in the left dorsolateral prefrontal cortex (DLPFC), left anterior cingulate cortex (ACC) and left occipital lobe as compared to those patients that did not use cannabis during the scan interval. First-episode schizophrenia patients who use cannabis show a more pronounced cortical thinning than non-using patients in areas known for their high density of CB1 receptors, such as the ACC and the DLPFC.     

A distributed frontotemporal network underlies gamma-band synchronization impairments in schizophrenia patients

Synaptic interactions between parvalbumin-positive γ-aminobutyric acid (GABA)-ergic interneurons and pyramidal neurons evoke cortical gamma oscillations, which are known to be abnormal in schizophrenia. These cortical gamma oscillations can be indexed by the gamma-band auditory steady-state response (ASSR), a robust electroencephalographic (EEG) biomarker that is increasingly used to advance the development of novel therapeutics for schizophrenia, and other related brain disorders. Despite promise of ASSR, the neural substrates of ASSR have not yet been characterized. This study investigated the sources underlying ASSR in healthy subjects and schizophrenia patients. In this study, a novel method for noninvasively characterizing source locations was developed and applied to EEG recordings obtained from 293 healthy subjects and 427 schizophrenia patients who underwent ASSR testing. Results revealed a distributed network of temporal and frontal sources in both healthy subjects and schizophrenia patients. In both groups, primary contributing ASSR sources were identified in the right superior temporal cortex and the orbitofrontal cortex. In conjunction with normal activity in these areas, schizophrenia patients showed significantly reduced source dipole density of gamma-band ASSR (ITC > 0.25) in the left superior temporal cortex, orbitofrontal cortex, and left superior frontal cortex. In conclusion, a distributed network of temporal and frontal brain regions supports gamma phase synchronization. We demonstrated that failure to mount a coherent physiologic response to simple 40-Hz stimulation reflects disorganized network function in schizophrenia patients. Future translational studies are needed to more fully understand the neural mechanisms underlying gamma-band ASSR network abnormalities in schizophrenia.Subject terms: Neurophysiology, Schizophrenia     

Cannabis,Cigarettes, and Their Co-Occurring Use: Disentangling Differences in Gray Matter Volume

Background:

Structural magnetic resonance imaging techniques are powerful tools for examining the effects of drug use on the brain. The nicotine and cannabis literature has demonstrated differences between nicotine cigarette smokers and cannabis users compared to controls in brain structure; however, less is known about the effects of co-occurring cannabis and tobacco use.

Methods:

We used voxel-based morphometry to examine gray matter volume differences between four groups: (1) cannabis-dependent individuals who do not smoke tobacco (Cs); (2) cannabis-dependent individuals who smoke tobacco (CTs); (3) cannabis-naïve, nicotine-dependent individuals who smoke tobacco (Ts); and (4) healthy controls (HCs). We also explored associations between gray matter volume and measures of cannabis and tobacco use.

Results:

A significant group effect was observed in the left putamen, thalamus, right precentral gyrus, and left cerebellum. Compared to HCs, the Cs, CTs, and Ts exhibited larger gray matter volumes in the left putamen. Cs also had larger gray matter volume than HCs in the right precentral gyrus. Cs and CTs exhibited smaller gray matter volume than HCs in the thalamus, and CTs and Ts had smaller left cerebellar gray matter volume than HCs.

Conclusions:

This study extends previous research that independently examined the effects of cannabis or tobacco use on brain structure by including an examination of co-occurring cannabis and tobacco use, and provides evidence that cannabis and tobacco exposure are associated with alterations in brain regions associated with addiction.