精神分裂症首次发病未治疗患者静息态下局部脑区自发活动的研究

目的探讨精神分裂症首次发病未治疗患者静息态下局部脑区自发活动的情况:方法:利用低频振幅(ALFF)方法,对27例首次发病未治疗的精神分裂症患者(患者组)进行静息状态下功能磁共振(fMRI)扫描,对影像学数据进行ALFF方法处理,结果与22名年龄、性别及受教育程度相匹配的健康对照者(正常对照组)比较。结果:与正常对照组相比,患者组ALFF显著增高的脑区是运动前区、辅助运动区和眶额回;ALFF显著降低的脑区是楔前叶、后扣带回、内侧前额叶和角回(P0.05,Alphaism矫正)。结论:精神分裂症首次发病未治疗患者在静息态下运动前区、辅助运动区、眶额回、楔前叶、后扣带回、内侧前额叶和角回的局部脑区自发活动异常,这些异常脑区可能有助于解释精神分裂症的病理机制。     

基于低频振幅方法的连枷臂综合征患者静息态功能磁共振成像研究

目的 采用静息态功能磁共振成像(RS-fMRI)低频振幅(ALFF)分析法,探讨连枷臂综合征(Flail arm syndrome,FAS)患者基线脑活动变化及意义。方法 对10名确诊的连枷臂综合征患者(连枷臂组)和10名与之年龄、性别、教育程度相匹配的正常成年人对照者(对照组)进行静息态磁共振成像扫描,应用ALFF分析法计算并比较两组受试者全脑的ALFF值的差异,并进一步分析其与临床症状严重程度的相关性。结果 静息态下,与正常对照组相比较,FAS组在双侧楔前叶、左侧楔叶、后扣带回、枕上回、颞中回、枕中回、角回、顶下缘角回脑区均出现ALFF值的低于正常对照组,但没有发现FAS组ALFF增高的脑区。ALFF明显减低的脑区的ALFF值与ALS功能分级量(ALSFRS-R)总分无相关性。结论 静息态下主要在双侧楔前叶、左侧楔叶、后扣带回、枕上回、颞中回、枕中回、角回、顶下缘角回脑区的脑功能活动异常,这些脑区ALFF改变可能与FAS的病理机制有关,但与FAS疾病严重程度无关。     

早期精神分裂症患者静息态脑功能低频振幅研究

目的:通过静息态功能磁共振探讨早期精神分裂症患者脑功能低频振幅变化。方法:对首次发病未用药早期精神分裂症患者(急性期组)、经药物治疗临床症状缓解的早期精神分裂症首次发病患者(缓解期组)以及性别、年龄、受教育年匹配的健康对照者(对照组)各17例,进行静息态功能磁共振扫描,并计算低频振幅(ALFF),比较3组ALFF变化。结果:三组间ALFF有差异的脑区为左侧直回、梭状回/舌回、右侧颞下回、左侧顶叶、枕叶、楔叶、中央后回、小脑;与健康对照组相比,两病例组ALFF降低的脑区集中在左侧半球,为左侧顶叶小叶,左侧颞下回;而缓解期与急性期组相比,ALFF增加的脑区为右侧壳核,ALFF降低的脑区为直回、楔前叶、梭状回/舌回、左侧颞叶、左侧中央前回和后回、左侧枕中回。结论:精神分裂症患者早期阶段存在多个脑区静息态低频振幅异常,低频振幅降低的脑区主要分布在左侧大脑半球。     

早发精神分裂症静息态脑功能低频振幅研究

目的通过静息态功能磁共振研究早发未用药精神分裂症患者局部脑功能低频振幅(amplitude of low-frequency fluctuation,ALFF)的变化,探讨其静息态下功能异常的脑区。方法收集20例早发未用药精神分裂症患者与20名性别、年龄、受教育年限相匹配的正常对照,分别对其进行全脑静息态功能磁共振扫描,计算ALFF值。结果与对照组相比,患者组左侧额上回、左侧楔前叶、左侧扣带回、左侧枕叶、左侧海马旁回、左侧距状沟ALFF值增高(P0.05,Alpha Sim校正),右侧颞上回和右侧小脑后叶ALFF值降低(P0.05,Alpha Sim校正)。结论早发精神分裂症患者在静息态下有多处脑区ALFF值改变,提示其在静息态下存在脑功能异常。     

复发性视神经炎静息态低频振幅功能磁共振成像研究

目的研究复发性视神经炎患者异常神经功能活动脑区的分布差异,探讨基线神经功能及其与临床的关系。方法采用基于低频振幅(ALFF)的静息态f MRI技术对35例复发性视神经炎患者进行研究,并与50例性别、年龄和受教育程度相匹配的正常对照者进行比较,并分析m ALFF值改变脑区与病程、同步听觉系列加法测验(PASAT)评分和视力之间的相关性。结果与正常对照组相比,复发性视神经炎组患者左侧楔叶/楔前叶、左侧颞上回、双侧颞下回、双侧舌回和右侧枕中回m ALFF值降低(P0.01),而双侧额下回和左侧额叶内侧回m ALFF值增加(P0.01)。复发性视神经炎患者仅左侧颞上回(r=0.403,P0.05)和右侧舌回(r=0.472,P0.05)m ALFF值与病程呈正相关。结论静息态f MRI可以检出复发性视神经炎患者参与视觉信息处理的颞枕叶神经功能降低,以及与脑默认网络相关的额叶神经功能增强,为早期评价视神经炎患者神经功能和预测预后提供客观依据。     

女性抑郁症快感缺失患者脑低频振幅特征

目的:探讨女性快感缺失与非快感缺失型抑郁症患者静息态下全脑活动的低频振幅(amplitude of low frequency fluctuations, ALFF)特征差异。方法:对83例女性快感缺失型抑郁症患者(快感缺失组)、83例女性非快感缺失型抑郁症患者(非快感缺失组)和83名女性健康志愿者(对照组)进行3.0 T静息态功能磁共振扫描,计算全脑ALFF值,并进行单因素方差分析,使用高斯随机场(GRF)的方法进行多重比较矫正并进行比较分析。结果:3组ALFF值在左颞上回、右脑岛、左楔前叶差异有统计学意义(P<0.01,GRF矫正);与对照组相比,快感缺失组与非快感缺失组皆在左颞上回、右脑岛ALFF值升高,左楔前叶ALFF值下降;快感缺失组较非快感缺失组在左楔前叶处ALFF值下降更显著。结论:女性抑郁症快感缺失与非快感缺失患者静息状态下脑区活动存在异常,且异常存在差异,可作为快感缺失型抑郁症可能的神经影像学标记。     

抑郁症患者岛叶-皮质静息态功能连接的观察北大核心CSCD

目的探讨未服药抑郁症患者静息态岛叶功能连接特征。方法选取50例未服药的抑郁症患者(抑郁症组)和51名健康对照者(对照组)进行静息态fMRI(rs-fMRI)扫描,对rs-fMRI数据进行常规预处理并基于岛叶分区为双侧岛叶前部、双侧岛叶中部、双侧岛叶后部6个种子点进行全脑功能连接分析,采用双样本t检验比较2组间脑功能连接值的差异,经过不依赖阈值集群增强(threshold-free cluster enhancement,TFCE)的多重比较校正,并将差异有统计学意义脑区的功能连接值与HAMD24评分等临床变量进行相关分析。结果与对照组相比,抑郁症组左侧岛叶前部与双侧前扣带回之间功能连接减低(t=-4.83,P<0.05,TFCE校正),左侧岛叶前部与左侧额中回、双侧后扣带回/楔前叶之间功能连接增强(t=4.08、4.42,均P<0.05,TFCE校正)。左侧岛叶前部与双侧前扣带回(r=-0.125,P=0.387)、左侧额中回(r=0.149,P=0.302)、双侧后扣带回/楔前叶(r=-0.207,P=0.148)的功能连接值与HMAD24评分无相关性。结论抑郁症患者可能存在左侧岛叶前部与边缘系统、额叶皮质功能连接异常,包括岛叶-前扣带回连接减弱,岛叶-额叶、岛叶-后扣带回/楔前叶连接增高。     

首发未治疗的精神分裂症患者低频振幅研究

目的:探讨首发未治疗的精神分裂症患者低频振幅(ALFF)改变及其与临床症状的关系。方法:对69例首次发病未治疗的精神分裂症患者(患者组)及74名健康对照者(对照组)进行静息态功能磁共振(fMRI)扫描获取ALFF值;采用阳性和阴性症状量表(PANSS)评估患者的临床症状,分析ALFF与临床症状的关系。结果:与对照组相比,患者组右颞中回、右脑岛、右尾状核、右额上回、右顶下小叶、左顶上回ALFF值明显增高,右楔叶ALFF值明显降低(高斯随机场矫正,体素P0.001;团块P0.05),患者组右额上回ALFF值与PANSS阳性症状分(多重比较矫正,r=0.30,P0.05)及总分(多重比较矫正,r=0.34,P0.05)呈正相关。结论:首发精神分裂症患者部分脑区脑功能活动异常,且异常活动脑区可能与临床症状相关。     

腰背痛患者静息态fMRI的脑功能局部一致性研究

目的 利用功能磁共振成像(fMRI)技术探讨静息状态下腰背痛患者脑局部一致性(ReHo)变化的特点. 方法 选择自2011年8月至2012年1月南方医科大学珠江医院康复医学科招募的15例年龄、性别和文化程度相近的健康者作为受试者,向其右侧腰背部肌肉注射0.3 mL30g/L的高渗盐水制造腰背痛模型,采用3.0T MR仪分别在注射前、注射后进行静息状态fMRI扫描,所得数据进行配对t检验,比较疼痛及非疼痛状态下静息态脑功能的局部一致性差异. 结果 与正常状态相比,腰背痛受试者ReHo增高的脑区有:双侧前额叶内侧、左额下回、右额中回、右小脑扁桃体、右脑桥、右岛叶、右尾状核、右楔前叶、右海马旁回、后扣带回;ReHo减低的脑区有:右颞上回、左颞中回、左中央前回、左中央后回、左海马旁回、左梭状回、左前扣带回、左顶上小叶、右顶下小叶(P＜0.005,体素值≥10). 结论 静息状态下腰背痛患者部分脑区存在脑活动区域一致性异常.     

重性抑郁症基于低频振幅的静息态功能磁共振成像研究

目的观察重性抑郁症患者静息态fMRI(rs-fMRI)特点,并探讨其可能发病机制。方法采用基于低频振幅(ALFF)的rs-f MRI对24例重性抑郁症患者和性别、年龄、受教育程度匹配的26例正常对照者进行比较,Spearman秩相关分析探讨各脑区mALFF值与汉密尔顿抑郁量表17项(HAMD-17)评分的相关性。结果与正常对照者相比,重性抑郁症患者双侧背外侧前额叶皮质、右侧眶部额上回、右侧颞下回、左侧岛盖部额下回、左侧内侧额上回、左侧直回mALFF值升高(均P0.05,AlphaSim校正),双侧补充运动区、右侧后扣带回、右侧楔前叶、左侧舌回mALFF值降低(均P0.05,AlphaSim校正)。Spearman秩相关分析显示,重性抑郁症患者各脑区mALFF值与HAMD-17评分无关联性(均P0.05)。结论重性抑郁症患者静息态下神经功能损害主要集中于脑默认网络和边缘系统等多个脑区,提示其可能存在特征性神经功能改变基础。     

Amygdala activity correlates with attentional bias in PTSD

Post-traumatic stress disorder (PTSD) is an anxiety disorder arising in the aftermath of a traumatic event. The most prevalent hypothesis is that of an increased amygdala activity to threat cues. The amygdala has also shown an implication in orienting attention toward threat. The aim of the study was to explore the correlations between amygdala activity, symptom severity and attentional bias in PTSD. Patients and healthy controls were assayed on an fMRI emotional face matching task and an attentional detection of target (DOT) task. The amygdala showed enhanced activity in PTSD (vs. controls). It positively correlated with anxiety scores and PTSD symptomatology. It also positively correlated with the disengagement index. Mostly, these results provide preliminary support for an implication of the amygdala in attention orientation to threat in PTSD. These results are further discussed in light of recent theories concerned with cortico-limbic functioning.     

Exaggerated amygdala response to masked facial stimuli in posttraumatic stress disorder: a functional MRI study.

BACKGROUND: Converging lines of evidence have implicated the amygdala in the pathophysiology of posttraumatic stress disorder (PTSD). We previously developed a method for measuring automatic amygdala responses to general threat-related stimuli; in conjunction with functional magnetic resonance imaging, we used a passive viewing task involving masked presentations of human facial stimuli. METHODS: We applied this method to study veterans with PTSD and a comparison cohort of combat-exposed veterans without PTSD. RESULTS: The findings indicate that patients with PTSD exhibit exaggerated amygdala responses to masked-fearful versus masked-happy faces. CONCLUSIONS: Although some previous neuroimaging studies of PTSD have demonstrated amygdala recruitment in response to reminders of traumatic events, this represents the first evidence for exaggerated amygdala responses to general negative stimuli in PTSD. Furthermore, by using a probe that emphasizes automaticity, we provide initial evidence of amygdala hyperresponsivity dissociated from the "top-down" influences of medial frontal cortex.     

Reduced amygdala and hippocampus size in trauma-exposed women with borderline personality disorder and without posttraumatic stress disorder

Background

Individuals with posttraumatic stress disorder (PTSD) display reduced hippocampus size and impaired cognition. However, studies on individuals with borderline personality disorder (BPD) are rare, and studies on trauma-exposed patients with BPD but without PTSD are lacking.

Methods

Twenty-four trauma-exposed women with BPD (10 with PTSD and 14 without) and 25 healthy controls underwent 3-dimensional structural magnetic resonance imaging of the amygdala and hippocampus and a clinical and neuropsychological investigation.

Results

Compared with controls, patients with BPD and PTSD displayed significantly reduced amygdala (34%) and hippocampus (12%) size and significantly impaired cognition. Trauma-exposed patients with BPD but without PTSD also showed significantly reduced amygdala (22%) and hippocampus (11%) size but normal cognition. Amygdala and hippocampus size did not differ significantly between patients with and without PTSD.

Limitations

The sample sizes of trauma-exposed groups are relatively small. A larger sample size may have revealed statistically significant differences in amygdala size between those with and without PTSD.

Conclusion

Our results demonstrate strong amygdala size reduction in trauma-exposed patients with BPD with or without PTSD, much exceeding that reported for trauma-exposed individuals without BPD. Our data suggest that BPD is associated with small amygdala size. Furthermore, evidence is increasing that amygdala and hippocampus size reduction is not only due to PTSD, but also to traumatic exposure.     

Differential time courses and specificity of amygdala activity in posttraumatic stress disorder subjects and normal control subjects.

BACKGROUND: Previous neuroimaging studies have demonstrated exaggerated amygdala responses to negative stimuli in posttraumatic stress disorder (PTSD). The time course of this amygdala response is largely unstudied and is relevant to questions of habituation and sensitization in PTSD exposure therapy. METHODS: We applied blood oxygen level dependent functional magnetic resonance imaging and statistical parametric mapping to study amygdala responses to trauma-related and nontrauma-related emotional words in sexual/physical abuse PTSD and normal control subjects. We examined the time course of this response by separate analysis of early and late epochs. RESULTS: PTSD versus normal control subjects have a relatively increased initial amygdala response to trauma-related negative, but not nontrauma-related negative, versus neutral stimuli. Patients also fail to show the normal patterns of sensitization and habituation to different categories of negative stimuli. These findings correlate with measured PTSD symptom severity. CONCLUSIONS: Our results demonstrate differential time courses and specificity of amygdala response to emotional and control stimuli in PTSD and normal control subjects. This has implications for pathophysiologic models of PTSD and treatment response. The results also extend previous neuroimaging studies demonstrating relatively increased amygdala response in PTSD and expand these results to a largely female patient population probed with emotionally valenced words.     

Neuroimaging findings in posttraumatic stress disorder: review of the literature

The knowledge about the development and maintenance of the posttraumatic stress disorder (PTSD) has increased significantly in the past 10 years with important insights coming from imaging studies. Through these insights PTSD has changed from "traumatic neurosis" to a biologically based psychological disorder. This paper summarises the recent literature on morphological, functional and metabolic neuroimaging on PTSD. Of special interest are four brain areas, the hyperactive amygdala, the hippocampus with volume reduction as well as the cingulate gyrus and orbitofrontal cortical regions, which may not be able to inhibit the hyperactive amygdala to trauma related stimuli. Based on these imaging data the current understanding of the pathophysiology of PTSD as well as present methodological limitations of imaging methods will be discussed.     

A functional magnetic resonance imaging study of amygdala and medial prefrontal cortex responses to overtly presented fearful faces in posttraumatic stress disorder

BACKGROUND: Previous functional neuroimaging studies have demonstrated exaggerated amygdala responses and diminished medial prefrontal cortex responses during the symptomatic state in posttraumatic stress disorder (PTSD). OBJECTIVES: To determine whether these abnormalities also occur in response to overtly presented affective stimuli unrelated to trauma; to examine the functional relationship between the amygdala and medial prefrontal cortex and their relationship to PTSD symptom severity in response to these stimuli; and to determine whether responsivity of these regions habituates normally across repeated stimulus presentations in PTSD. DESIGN: Case-control study. SETTING: Academic medical center. PARTICIPANTS: Volunteer sample of 13 men with PTSD (PTSD group) and 13 trauma-exposed men without PTSD (control group). MAIN OUTCOME MEASURES: We used functional magnetic resonance imaging (fMRI) to study blood oxygenation level-dependent signal during the presentation of emotional facial expressions. RESULTS: The PTSD group exhibited exaggerated amygdala responses and diminished medial prefrontal cortex responses to fearful vs happy facial expressions. In addition, in the PTSD group, blood oxygenation level-dependent signal changes in the amygdala were negatively correlated with signal changes in the medial prefrontal cortex, and symptom severity was negatively related to blood oxygenation level-dependent signal changes in the medial prefrontal cortex. Finally, relative to the control group, the PTSD group tended to exhibit diminished habituation of fearful vs happy responses in the right amygdala across functional runs, although this effect did not exceed our a priori statistical threshold. CONCLUSIONS: These results provide evidence for exaggerated amygdala responsivity, diminished medial prefrontal cortex responsivity, and a reciprocal relationship between these 2 regions during passive viewing of overtly presented affective stimuli unrelated to trauma in PTSD.     

Traumatic stress: effects on the brain

Brain areas implicated in the stress response include the amygdala, hippocampus, and prefrontal cortex. Traumatic stress can be associated with lasting changes in these brain areas. Traumatic stress is associated with increased cortisol and norepinephrine responses to subsequent stressors. Antidepressants have effects on the hippocampus that counteract the effects of stress. Findings from animal studies have been extended to patients with post-traumatic stress disorder (PTSD) showing smaller hippocampal and anterior cingulate volumes, increased amygdala function, and decreased medial prefrontal/anterior cingulate function. In addition, patients with PTSD show increased cortisol and norepinephrine responses to stress. Treatments that are efficacious for PTSD show a promotion of neurogenesis in animal studies, as well as promotion of memory and increased hippocampal volume in PTSD.     

Neural networks of information processing in posttraumatic stress disorder: a functional magnetic resonance imaging study.

BACKGROUND: Neuroimaging studies report reduced medial prefrontal cortical (particularly anterior cingulate) but enhanced amygdala response to fear signals in posttraumatic Stress Disorder (PTSD). We investigated whether anterior cingulate-amygdala dysregulation in PTSD would generalize to salient, but nonthreat related signals. METHODS: Individuals with PTSD (n = 14) and age and sex-matched nontraumatized controls (n = 14) completed an auditory oddball paradigm adapted to functional magnetic resonance imaging at a 1.5-T field strength. RESULTS: Controls displayed bilateral activation in ventral anterior cingulate and amygdala networks, and PTSD subjects showed bilateral dorsal anterior cingulate and amygdala activation to targets relative to nontargets. Compared to controls, PTSD subjects showed enhanced responses to targets in the dorsal and rostral anterior cingulate, and left amygdala. Whole-brain analyses confirmed the expected pattern of distributed prefrontal-parietal responses to targets in the oddball task. Greater activity in posterior parietal somatosensory regions was observed in PTSD. CONCLUSIONS: Our findings of enhanced anterior cingulate responses in PTSD contrast with reports of reduced activity for threat stimuli, suggesting that the latter may be specific to processing of threat-related content. Activation in rostral and dorsal anterior cingulate, left amygdala and posterior parietal networks in response to salient, nonthreatening stimuli may reflect generalized hypervigilance.