静息态fMRI在无痴呆型血管性认知障碍基线脑活动变化中的初步研究

目的 利用基于低频振幅算法(ALFF)的静息功能磁共振成像(fMRI)技术探讨无痴呆型血管性认知障碍(VCIND)与正常老年人静息状态下默认网络的改变情况.方法 将22例VCIND患者作为研究对象,23名正常老年人作为对照组,采用ALFF分析方法,比较两组平均脑ALFF图的差异.结果 VCIND患者在静息状态下较对照组在以下脑区ALFF值增高:左额下回/左颞上回(Maximum Z=-4.0682)、右额下回/右颞上回(Maximum Z=-3.9720)、左侧岛叶(Maximum Z=-3.5773);VCIND组患者在以下脑区出现ALFF值减低:舌回/小脑后叶(Maximum Z =3.8921)、前扣带皮层(Maximum Z=3.8081)、右楔叶/右舌回(Maximum Z=4.8272)、后扣带回/楔前叶(Maximum Z=3.9741)(P＜0.05).结论 VCIND患者在静息状态下ALFF有显著改变,主要表现为语言中枢等认知区域的局部ALFF增强及默认网络等功能连接点的ALFF减低.     

功能磁共振在精神障碍性疾病中的研究进展

功能磁共振成像(resting-state functional magnetic resonance imaging,fMR)l为探索脑工作机制和规律提供了一新思路和方法.其中联合应用静息态功能磁共振成像(fMR)I与弥散张量成像技术(DT)I,在探讨研究精神障碍性患者静息态功能连接与解剖连接的关系方面有一定临床价值.本文就功能磁共振在常见精神障碍性疾病方面的研究进行综述.     

Neural changes after Emotional Freedom Techniques treatment for chronic pain sufferers

This clinical trial investigated the effect of an Emotional Freedom Techniques (EFT) intervention on brain activation in chronic pain sufferers using functional magnetic resonance imaging (fMRI). EFT is a brief stress reduction technique which combines stating a cognitive statement with somatic tapping on acupressure points. Twenty-four adults were allocated to a six-week online group EFT treatment and underwent resting-state fMRI pre and post the intervention. A repeated measures MANOVA indicated significant differences in the levels of pain severity (−21%), pain interference (−26%), quality of life (+7%), somatic symptoms (−28%), depression (−13.5%), anxiety (−37.1%), happiness (+17%), and satisfaction with life (+8.8%) from pre-to post-test. Cohen's effect sizes ranged from small (0.2) to large (0.75) values suggesting significance for the intervention. fMRI analysis showed post-EFT treatment significantly decreased connectivity between the medial prefrontal cortex (a pain modulating area) and bilateral grey matter areas in the posterior cingulate cortex and thalamus, both areas being related to modulating and catastrophizing of pain. There were no brain areas that showed significantly increased connectivity post-EFT treatment. Coupled with the psychological measures the findings support the effects of the EFT intervention in reducing chronic pain and its impacts. Recommendations for future research are discussed.     

Miswiring the brain: Human prenatal Δ9-tetrahydrocannabinol use associated with altered fetal hippocampal brain network connectivity

Increasing evidence supports a link between maternal prenatal cannabis use and altered neural and physiological development of the child. However, whether cannabis use relates to altered human brain development prior to birth, and specifically, whether maternal prenatal cannabis use relates to connectivity of fetal functional brain systems, remains an open question. The major objective of this study was to identify whether maternal prenatal cannabis exposure (PCE) is associated with variation in human brain hippocampal functional connectivity prior to birth. Prenatal drug toxicology and fetal fMRI data were available in a sample of 115 fetuses [43 % female; mean age 32.2 weeks (SD = 4.3)]. Voxelwise hippocampal connectivity analysis in a subset of age and sex-matched fetuses revealed that PCE was associated with alterations in fetal dorsolateral, medial and superior frontal, insula, anterior temporal, and posterior cingulate connectivity. Classification of group differences by age 5 outcomes suggest that compared to the non-PCE group, the PCE group is more likely to have increased connectivity to regions associated with less favorable outcomes and to have decreased connectivity to regions associated with more favorable outcomes. This is preliminary evidence that altered fetal neural connectome may contribute to neurobehavioral vulnerability observed in children exposed to cannabis in utero.     

基于静息态功能磁共振技术研究针灸调节病理状态的进展

查阅运用静息态功能磁共振(fMRI)技术探讨针灸调节病理状态的研究文献,分析针灸效应中枢作用机制的研究情况,结果表明:1针刺机制研究较之于灸法机制研究,数量上稍多,质量稍高;2研究主要集中于针刺镇痛,针刺镇痛的中枢机制已经初步定位于针刺对"疼痛矩阵"脑区和疼痛相关默认网络的靶向性调节,而针灸其它效应的中枢机制尚处于探索之中;3研究方案中多选用单一穴位,较少关注穴位配伍。故建议今后关于静息态fMRI与针灸机制相关的研究需加强灸法应用的中枢机制探讨,考虑与临床实际治疗方案一致的研究设计。     

Extracting biomarkers of autism from MEG resting-state functional connectivity networks

The present study is a preliminary attempt to use graph theory for deriving distinct features of resting-state functional networks in young adults with autism spectrum disorder (ASD). Networks modeled neuromagnetic signal interactions between sensors using three alternative interdependence measures: (a) a non-linear measure of generalized synchronization (robust interdependence measure [RIM]), (b) mutual information (MI), and (c) partial directed coherence (PDC). To summarize the information contained in each network model we employed well-established global graph measures (average strength, assortativity, clustering, and efficiency) as well as graph measures (average strength of edges) tailored to specific hypotheses concerning the spatial distribution of abnormalities in connectivity among individuals with ASD. Graph measures then served as features in leave-one-out classification analyses contrasting control and ASD participants. We found that combinations of regionally constrained graph measures, derived from RIM, performed best, discriminating between the two groups with 93.75% accuracy. Network visualization revealed that ASD participants displayed significantly reduced interdependence strength, both within bilateral frontal and temporal sensors, as well as between temporal sensors and the remaining recording sites, in agreement with previous studies of functional connectivity in this disorder.     

BOLD signal variability and complexity in children and adolescents with and without autism spectrum disorder

Variability of neural signaling is an important index of healthy brain functioning, as is signal complexity, which relates to information processing capacity. Alterations in variability and complexity may underlie certain brain dysfunctions. Here, resting-state fMRI was used to examine variability and complexity in children and adolescents with and without autism spectrum disorder (ASD). Variability was measured using the mean square successive difference (MSSD) of the time series, and complexity was assessed using sample entropy. A categorical approach was implemented to determine if the brain measures differed between diagnostic groups (ASD and controls). A dimensional approach was used to examine the continuum of relationships between each brain measure and behavioral severity, age, IQ, and the global efficiency (GE) of each participant’s structural connectome, which reflects the structural capacity for information processing. Using the categorical approach, no significant group differences were found for neither MSSD nor entropy. The dimensional approach revealed significant positive correlations between each brain measure, GE, and age. Negative correlations were observed between each brain measure and the severity of ASD behaviors across all participants. These results reveal the nature of variability and complexity of BOLD signals in children and adolescents with and without ASD.     

Resting-state EEG gamma power and theta–gamma coupling enhancement following high-frequency left dorsolateral prefrontal rTMS in patients with depression

Objective

We aimed to investigate neuromodulatory effects of high-frequency left dorsolateral prefrontal cortex repetitive transcranial magnetic stimulation (rTMS) on resting-state electroencephalography (EEG) and their clinical and cognitive correlates in patients with depression.

Increased power spectral density in resting-state pain-related brain networks in fibromyalgia

Fibromyalgia (FM), characterized by chronic widespread pain, is known to be associated with heightened responses to painful stimuli and atypical resting-state functional connectivity among pain-related regions of the brain. Previous studies of FM using resting-state functional magnetic resonance imaging (rs-fMRI) have focused on intrinsic functional connectivity, which maps the spatial distribution of temporal correlations among spontaneous low-frequency fluctuation in functional MRI (fMRI) resting-state data. In the current study, using rs-fMRI data in the frequency domain, we investigated the possible alteration of power spectral density (PSD) of low-frequency fluctuation in brain regions associated with central pain processing in patients with FM. rsfMRI data were obtained from 19 patients with FM and 20 age-matched healthy female control subjects. For each subject, the PSDs for each brain region identified from functional connectivity maps were computed for the frequency band of 0.01 to 0.25 Hz. For each group, the average PSD was determined for each brain region and a 2-sample t test was performed to determine the difference in power between the 2 groups. According to the results, patients with FM exhibited significantly increased frequency power in the primary somatosensory cortex (S1), supplementary motor area (SMA), dorsolateral prefrontal cortex, and amygdala. In patients with FM, the increase in PSD did not show an association with depression or anxiety. Therefore, our findings of atypical increased frequency power during the resting state in pain-related brain regions may implicate the enhanced resting-state baseline neural activity in several brain regions associated with pain processing in FM.     

重复经颅磁刺激治疗急性缺血性脑卒中疗效的功能磁共振成像评价

目的 利用静息态功能磁共振成像（resting-state functional magnetic resonance imaging,rs-fMRI）技术观察缺血性脑卒中患者重复经颅磁刺激（repetitive transcranial magnetic stimulation,rTMS）治疗前后两侧初级运动皮质（M1）功能连接的特点,进而为康复治疗找寻脑功能重组的证据.方法 对5例发病l周内单侧发病的缺血性脑卒中患者在重复经颅磁刺激（rTMS）治疗前后各进行1次静息态功能磁共振（rs-fMRI）检查和临床功能评分.同时选取正常志愿者25例作为正常对照组,只进行1次rs-fMRI检查.通过分析rs-fMRI两侧M1区功能连接值的改变,比较患者治疗前、后组与正常对照组之间功能连接变化的差异.结果 患者治疗前组两侧M1区功能连接值降低（z=0.30±0.24）,低于正常对照组（z=0.70±0.21）,治疗后连接值升高（z=0.58±0.28）,治疗前组与正常组之间的差异及治疗前后组的差异具有统计学意义（P＜0.05）,但治疗后组与正常对照组两侧M1区功能连接值之间无统计学意义（P＞0.05）.与患者治疗前组相比,治疗后组患侧肢体美国国立卫生院神经功能缺损评分（National Institutes of Health Stroke Scale,NIHSS）评分显著降低（P＜0.05）、患侧上下肢体Fugl-Meyer评分（Fugl-Meyer assessment,FMA）显著升高（P＜0.05）、日常生活指数（barthel index,BI）显著升高（P＜0.05）,提示患者治疗后功能改善.结论 通过静息态功能磁共振检查可以监测高频rTMS治疗前后两侧M1区功能连接的变化,客观地证实rTMS治疗是安全有效的康复治疗手段,推测康复治疗的黄金时间窗可能位于1个月内.