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find Keyword "功能连接" 12 results
  • 颞叶癫痫的海马网络功能连接

    由于海马和其他颞叶结构与其他脑区存在连接, 颞叶癫痫(TLE)可以影响到颞叶以外的结构。采用磁共振(MRI)功能连接的方法来探索TLE海马网络的变化, 以更全面的分析TLE的异常分布范围。共纳入三组被试:左侧颞叶癫痫TLE组(13例); 右侧TLE组(11例)及健康对照组(16例)。分别在这三组被试中划定左、右两侧海马为感兴趣区(Regions of interest, ROIs)。通过测定静息态功能磁共振(functional MRI, fMRI)低频血氧水平(Blood oxygenation level dependent, BOLD)信号的相关性来寻找与ROIs存在着功能连接的脑区。采用独立样本t检验进行组间对比。在TLE中, 海马与多个脑区功能连接增强, 包括边缘系统中的几个关键区域(颞叶、岛叶、丘脑)、额叶、角回、基底节、脑干和小脑, 同时海马与一些脑区之间的功能连接减弱, 包括感觉运动皮质(视觉、体感、听觉、初级运动)和默认网络(楔前叶)。左侧TLE的功能连接改变较右侧TLE更为明显。TLE功能连接改变揭示了TLE累及多个脑区, 导致大脑神经网络功能失常。左侧TLE和右侧TLE的海马功能连接存在显著差异。

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  • The Impact of Mood on the Intrinsic Functional Connectivity

    Although a great number of studies have investigated the changes of resting-state functional connectivity (rsFC) in patients with mental disorders, such as depression and schizophrenia etc, little is known how stable the changes are, and whether temporal sad or happy mood can modulate the intrinsic rsFC. In our experiments, happy and sad video clips were used to induce temporally happy and sad mood states in 20 healthy young adults. We collected functional magnetic resonance imaging (fMRI) data while participants were watching happy or sad video clips, which were administrated in two consecutive days. Seed-based functional connectivity analyses were conducted using the anterior cingulate cortex (ACC), dorsolateral prefrontal cortex (DLPFC), and amygdala as seeds to investigate neural network related to executive function, attention, and emotion. We also investigated the association of the rsFC changes with emotional arousability level to understand individual differences. There is significantly stronger functional connectivity between the left DLPFC and posterior cingulate cortex (PCC) under sad mood than that under happy mood. The increased connectivity strength was positively correlated with subjects' emotional arousability. The increased positive correlation between the left DLPFC and PCC under sad relative to happy mood might reflect an increased processing of negative emotion-relevant stimuli. The easier one was induced by strong negative emotion (higher emotional arousability), the greater the left DLPFC-PCC connectivity was indicated, the greater the instability of the intrinsic rsFC was shown.

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  • Study on Brain Functional Connectivity Using Resting State Electroencephalogram Based on Synchronization Likelihood in Alzheimer's Disease

    Alzheimer's disease (AD) is the most common type of dementia and a neurodegenerative disease with progressive cognitive dysfunction as the main feature. How to identify the early changes of cognitive dysfunction and give appropriate treatments is of great significance to delay the onset of dementia. Some other researches have shown that AD is associated with abnormal changes of brain networks. To study human brain functional connectivity characteristics in AD, 16 channels electroencephalogram (EEG) were recorded under resting and eyes-closed condition in 15 AD patients and 15 subjects in the control group. The synchronization likelihood of the full-band and alpha-band (8-13 Hz) data were evaluated, which resulted in the synchronization likelihood coefficient matrices. Considering a threshold T, the matrices were converted into binary graphs. Then the graphs of two groups were measured by topological parameters including the clustering coefficient and global efficiency. The results showed that the global efficiency of the network in full-band EEG was significantly smaller in AD group for the values of T=0.06 and T=0.07, but there was no statistically significant difference in the clustering coefficients between the two groups for the values of T (0.05-0.07). However, the clustering coefficient and global efficiency were significantly lower in AD patients at alpha-band for the same threshold range than those of subjects in the control group. It suggests that there may be decreases of the brain connectivity strength in AD patients at alpha-band of the resting-state EEG. This study provides a support for quantifying functional brain state of AD from the brain network perspective.

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  • Research on the characteristics of the dynamic functional connectivity network related to aging

    Brain aging can affect the strength of functional connectivity between brain regions. In recent years, studies have shown that functional connectivity is fluctuant over time, and can reflect more physiological and pathological information. Therefore, in the study resting state functional magnetic resonance imaging (fMRI) data of 32 elderly subjects and 36 younger subjects were selected, and the sliding window technique was used to estimate dynamic functional connectivity network. Then, the dependency of fluctuating energy difference on frequency band was studied using wavelet packet analysis, conducting the linear regression with age at the same time. Results showed that the fluctuating energy in older group was significantly higher than that in the young group in low frequency, and it was significantly lower than that in the young people in high frequency. These results suggested that the dynamic functional connectivity between networks in the elderly exist slow wave phenomenon, which may be related to the decreased reaction rate of the elderly. This article provides new ideas and methods for the research about brain aging, and promotes a theoretical basis for further understanding of the physiological significance of brain dynamic functional connectivity.

    Release date:2017-04-13 10:03 Export PDF Favorites Scan
  • Research on effects of low-frequency repetitive transcranial magnetic stimulation over primary motor cortex on functional connectivity of brain

    Repetitive transcranial magnetic stimulation (rTMS) can influence the stimulated brain regions and other distal brain regions connecting to them. The purpose of the study is to investigate the effects of low-frequency rTMS over primary motor cortex on brain by analyzing the brain functional connectivity and coordination between brain regions. 10 healthy subjects were recruited. 1 Hz rTMS was used to stimulate primary motor cortex for 20 min. 1 min resting state electroencephalography (EEG) was collected before and after the stimulation respectively. By performing phase synchronization analysis between the EEG electrodes, the brain functional network and its properties were calculated. Signed-rank test was used for statistical analysis. The result demonstrated that the global phase synchronization in alpha frequency band was decreased significantly after low-frequency rTMS (P<0.05). The phase synchronization was down-regulated between motor cortex and ipsilateral frontal/parietal cortex, and also between contralateral parietal cortex and bilateral frontal cortex. The mean degree and global efficiency of brain functional networks in alpha frequency band were significantly decreased (P<0.05), and the mean shortest path length were significantly increased (P<0.05), which suggested the information transmission of the brain networks and its efficiency was reduced after low-frequency rTMS. This study verified the inhibition function of the low-frequency rTMS to brain activities, and demonstrated that low-frequency rTMS stimulation could affect both stimulating brain regions and distal brain regions connected to them. The findings in this study could be of guidance to clinical application of low-frequency rTMS.

    Release date:2017-08-21 04:00 Export PDF Favorites Scan
  • Research progress about different levels of cognitive recession using resting state functional connectivity network methods

    Normal brain aging and a serious of neurodegenerative diseases may lead to decline in memory, attention and executive ability and poorer quality of life. The mechanism of the decline is not clear now and is still a hot issue in the fields of neuroscience and medicine. A large number of researches showed that resting state functional brain networks based functional magnetic resonance imaging (fMRI) are sensitive and susceptive to the change of cognitive function. In this paper, the researches of brain functional connectivity based on resting fMRI in recent years were compared, and the results of subjects with different levels of cognitive decline including normal brain aging, mild cognitive impairment (MCI) and Alzheimer’s disease (AD) were reviewed. And the changes of brain functional networks under three different levels of cognitive decline are introduced in this paper, which will provide the basis for the detection of normal brain aging and clinical diseases.

    Release date:2017-08-21 04:00 Export PDF Favorites Scan
  • 癫痫网络的定义:立体脑电图和信号分析的贡献

    致痫网络定义为癫痫放电产生和传播过程中累及的脑区。基于颅内电极电生理数据的分析,文章综述介绍了致痫网络的历史、方法和概念。在癫痫术前评估中,确定产生癫痫发作的脑区(如致痫区)是最重要的目标。较药物难治性局灶性癫痫传统的、局限性的视觉分析方法而言,致痫网络作为一个模型已逐渐得到公认。该模型能更好地描述发作动态演变的复杂性、更真实地描述大脑致痫性的异常分布。致痫网络概念在历史上与立体脑电图(SEEG)方法学的发展及随后脑电信号定量分析相关。SEEG 有明确的发作期、发作前及发作间期放电模式,可以用信号分析方法对上述模式进行分析,如高频振荡定量分析或分析功能连接的改变。我们可以在皮层和皮层下脑区癫痫发生和传播的过程中,依据 SEEG 数据分析得到大脑连接的显著变化,这些变化与不同的发作症状学模式相关。发作间期特征就是致痫网络产生异常电活动(发作间期棘波)及功能连接的改变。致痫网络大尺度建模新方法的引入为更好地预测手术预后提供了新方法。就明确致痫性脑区的分布而言,致痫网络的概念是一个关键的要素,这对癫痫手术尤为重要。

    Release date:2018-03-20 04:09 Export PDF Favorites Scan
  • A multi-parameter resting-state functional magnetic resonance imaging study of brain intrinsic activity in attention deficit hyperactivity disorder children

    A great number of studies have demonstrated functional abnormalities in children with attention-deficit/hyperactivity disorder (ADHD), although conflicting results have also been reported. And few studies analyzed homotopic functional connectivity between hemispheres. In this study, resting-state functional magnetic resonance imaging (MRI) data were recorded from 45 medication-naïve ADHD children and 26 healthy controls. The regional homogeneity (ReHo), degree centrality (DC) and voxel-mirrored homotopic connectivity (VMHC) values were compared between the two groups to depict the intrinsic brain activities. We found that ADHD children exhibited significantly lower ReHo and DC values in the right middle frontal gyrus and the two values correlated with each other; moreover, lower VMHC values were found in the bilateral occipital lobes of ADHD children, which was negatively related with anxiety scores of Conners' Parent Rating Scale (CPRS-R) and positively related with completed categories of Wisconsin Card Sorting Test (WCST). Our results might suggest that less spontaneous neuronal activities of the right middle frontal gyrus and the bilateral occipital lobes in ADHD children.

    Release date:2018-08-23 03:47 Export PDF Favorites Scan
  • Study of functional connectivity during anesthesia based on sparse partial least squares

    Anesthesia consciousness monitoring is an important issue in basic neuroscience and clinical applications, which has received extensive attention. In this study, in order to find the indicators for monitoring the state of clinical anesthesia, a total of 14 patients undergoing general anesthesia were collected for 5 minutes resting electroencephalogram data under three states of consciousness (awake, moderate and deep anesthesia). Sparse partial least squares (SPLS) and traditional synchronized likelihood (SL) are used to calculate brain functional connectivity, and the three conscious states before and after anesthesia were distinguished by the connection features. The results show that through the whole brain network analysis, SPLS and traditional SL method have the same trend of network parameters in different states of consciousness, and the results obtained by SPLS method are statistically significant (P<0.05). The connection features obtained by the SPLS method are classified by the support vector machine, and the classification accuracy is 87.93%, which is 7.69% higher than that of the connection feature classification obtained by SL method. The results of this study show that the functional connectivity based on the SPLS method has better performance in distinguishing three kinds of consciousness states, and may provides a new idea for clinical anesthesia monitoring.

    Release date:2020-08-21 07:07 Export PDF Favorites Scan
  • Cross subject personality assessment based on electroencephalogram functional connectivity and domain adaptation

    The research shows that personality assessment can be achieved by regression model based on electroencephalogram (EEG). Most of existing researches use event-related potential or power spectral density for personality assessment, which can only represent the brain information of a single region. But some research shows that human cognition is more dependent on the interaction of brain regions. In addition, due to the distribution difference of EEG features among subjects, the trained regression model can not get accurate results of cross subject personality assessment. In order to solve the problem, this research proposes a personality assessment method based on EEG functional connectivity and domain adaption. This research collected EEG data from 45 normal people under different emotional pictures (positive, negative and neutral). Firstly, the coherence of 59 channels in 5 frequency bands was taken as the original feature set. Then the feature-based domain adaptation was used to map the feature to a new feature space. It can reduce the distribution difference between training and test set in the new feature space, so as to reduce the distribution difference between subjects. Finally, the support vector regression model was trained and tested based on the transformed feature set by leave-one-out cross-validation. What’s more, this paper compared the methods used in previous researches. The results showed that the method proposed in this paper improved the performance of regression model and obtained better personality assessment results. This research provides a new method for personality assessment.

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