Electroencephalogram Signal Correlations between Default Mode Network and Attentional Functioning

Attentional issues may affect acquiring new information, task performance, and learning. Cortical network activities change during different functional brain states, including the default mode network (DMN) and attention network. We investigated the neural mechanisms underlying attentional functions and correlations between DMN connectivity and attentional function using the Trail-Making Test (TMT)-A and -B. Electroencephalography recordings were performed by placing 19 scalp electrodes per the 10 - 20 system. The mean power level was calculated for each rest and task condition. Non-parametric Spearman’s rank correlation was used to examine the correlation in power levels between the rest and TMT conditions. The most significant correlations during TMT-A were observed in the high gamma wave, followed by theta and beta waves, indicating that most correlations were in the parietal lobe, followed by the frontal, central, and temporal lobes. The most significant correlations during TMT-B were observed in the beta wave, followed by the high and low gamma waves, indicating that most correlations were in the temporal lobe, followed by the parietal, frontal, and central lobes. Frontoparietal beta and gamma waves in the DMN may represent attentional functions.

The default mode network is affected in the early stage of simian immunodeficiency virus infection:a longitudinal study

Acquired immune deficiency syndrome infection can lead to cognitive dysfunction represented by changes in the default mode network.Most recent studies have been cross-sectional and thus have not revealed dynamic changes in the default mode network following acquired immune deficiency syndrome infection and antiretroviral therapy.Specifically,when brain imaging data at only one time point are analyzed,determining the duration at which the default mode network is the most effective following antiretroviral therapy after the occurrence of acquired immune deficiency syndrome.However,because infection times and other factors are often uncertain,longitudinal studies cannot be conducted directly in the clinic.Therefore,in this study,we performed a longitudinal study on the dynamic changes in the default mode network over time in a rhesus monkey model of simian immunodeficiency virus infection.We found marked changes in default mode network connectivity in 11 pairs of regions of interest at baseline and 10 days and 4 weeks after virus inoculation.Significant interactions between treatment and time were observed in the default mode network connectivity of regions of interest pairs area 31/V6.R and area 8/frontal eye field(FEF).L,area 8/FEF.L and caudal temporal parietal occipital area(TPOC).R,and area 31/V6.R and TPOC.L.ART administered 4 weeks after infection not only interrupted the progress of simian immunodeficiency virus infection but also preserved brain function to a large extent.These findings suggest that the default mode network is affected in the early stage of simian immunodeficiency virus infection and that it may serve as a potential biomarker for early changes in brain function and an objective indicator for making early clinical intervention decisions.

Resting state brain default network in patients with motor aphasia resulting from cerebral infarction

To explore the brain default mode network(DMN)in patients with motor aphasia resulting from cerebral infarction,we used resting state functional magnetic resonance imaging(fMRI)to investigate the possible neural mechanism.Thirteen patients with motor aphasia resulting from cerebral infarction and ten matched controls were selected in this study.All subjects were examined using resting state fMRI.We chose the posterior cingulate cortex as the region of interest and then used functional connectivity analysis to calculate the DMN functional connectivity and analyze differences in the functional connectivity between the two groups.Compared with normal controls,aphasia patient group showed a significantly decreased functional connectivity in bilateral medial frontal gyrus,superior frontal gyrus,middle frontal gyrus,middle temporal gyrus,precuneus and cuneus.The aphasia patient group showed increased functional connectivity mainly in bilateral medial frontal gyrus,middle frontal gyrus,inferior frontal gyrus,precentral gyrus,insula.The DMN in cerebral infarction motor aphasia patients showed significantly decreased functional connectivity in the resting state.The DMN most likely plays an important role in motor aphasia resulting from cerebral infarction.Furthermore,functional connectivity in the brain regions surrounding the left and right Broca’s areas was significantly enhanced due to compensatory mechanisms.This may be helpful for the recovery of language function in cerebral infarction patients with motor aphasia.

Resting-state connectivity in the default mode network and insula during experimental low back pain

Functional magnetic resonance imaging studies have shown that the insular cortex has a signif- icant role in pain identification and information integration, while the default mode network is associated with cognitive and memory-related aspects of pain perception. However, changes in the functional connectivity between the defauk mode network and insula during pain remain unclear. This study used 3.0 T functional magnetic resonance imaging scans in 12 healthy sub- jects aged 24.8 ± 3.3 years to compare the differences in the functional activity and connectivity of the insula and default mode network between the baseline and pain condition induced by intramuscular injection of hypertonic saline. Compared with the baseline, the insula was more functionally connected with the medial prefrontal and lateral temporal cortices, whereas there was lower connectivity with the posterior cingulate cortex, precuneus and inferior parietal lobule in the pain condition. In addition, compared with baseline, the anterior cingulate cortex exhibited greater connectivity with the posterior insula, but lower connectivity with the anterior insula, during the pain condition. These data indicate that experimental low back pain led to dysfunction in the connectivity between the insula and default mode network resulting from an impairment of the regions of the brain related to cognition and emotion, suggesting the impor- tance of the interaction between these regions in pain processing.

Altered amplitude of low-frequency fluctuations and default mode network connectivity in high myopia:a resting-state fMRI study

AIM:To analyze changes in amplitude of low-frequency fluctuations(ALFFs)and default mode network(DMN)connectivity in the brain,using resting-state functional magnetic resonance imaging(rs-fMRI),in high myopia(HM)patients.METHODS:Eleven patients with HM(HM group)and 15 age-and sex-matched non-HM controls(non-HM group)were recruited.ALFFs were calculated and compared between HM group and non-HM group.Independent component analysis(ICA)was conducted to identify DMN,and comparisons between DMNs of two groups were performed.Region-of-interest(ROI)-based analysis was performed to explore functional connectivity(FC)between DMN regions.RESULTS:Significantly increased ALFFs in left inferior temporal gyrus(ITG),bilateral rectus gyrus(REC),bilateral middle temporal gyrus(MTG),left superior temporal gyrus(STG),and left angular gyrus(ANG)were detected in HM group compared with non-HM group(all P<0.01).HM group showed increased FC in the posterior cingulate gyrus(PCC)/precuneus(preCUN)and decreased FC in the left medial prefrontal cortex(mPFG)within DMN compared with nonHM group(all P<0.01).Compared with non-HM group,HM group showed higher FC between mPFG and bilateral middle frontal gyrus(MFG),ANG,and MTG(all P<0.01).In addition,HM patients showed higher FC between PCC/(preCUN)and the right cerebellum,superior frontal gyrus(SFG),left pre CUN,superior frontal gyrus(SFG),and medial orbital of the superior frontal gyrus(ORB supmed;all P<0.01).CONCLUSION:HM patients show different ALFFs and DMNs compared with non-HM subjects,which may imply the cognitive alterations related to HM.

Changes in the default mode network in the prefrontal lobe, posterior cingulated cortex and hippocampus of heroin users

The default mode network is associated with senior cognitive functions in humans. In this study, we performed independent component analysis of blood oxygenation signals from 14 heroin users and 13 matched normal controls in the resting state through functional MRI scans. Results showed that the default mode network was significantly activated in the prefrontal lobe, posterior cingulated cortex and hippocampus of heroin users, and an enhanced activation signal was observed in the right inferior parietal Iobule （P 〈 0.05, corrected for false discovery rate）. Experimental findings indicate that the default mode network is altered in heroin users.

From Biological Rhythms to the Default Mode Network: What Lies beneath the Tip of the Iceberg of Mind?

Our conscious day-to-day self is often described as the “tip of the iceberg” of a much greater cognitive system. The edge of the water divides the phenomenal self from the sub/unconscious underlying it. Similar to an iceberg, the unconscious activity below the water vastly outweighs the conscious activity above it. What exactly lies beneath the surface of this murky water is a tantalizing topic of research and theory. The current research predominantly focuses on the physiology of the brain and the default mode network has been identified as an intrinsic mode of functioning. It is well known that autonomic nervous system sympathovagal balance orchestrated by the central autonomic network is strongly associated with modulation of cardiac, respiratory rate and other visceral physiological activity. In this article, we use existing research and a novel theory to tie together the default mode network, the autonomic nervous system, and non-neural physiology to describe a hypothesis on a greater biological system from which intrinsic brain activity may be founded. This hypothesis is that intrinsic brain activity and connectivities are significantly founded on activity of the body. We review how cardiorespiratory and other rhythms and electrical activity of the body may modulate and even underlie fundamental activity of the human brain and ultimately the mind. A more holistic biological system that could interface the brain and body via mechanisms such as neurovascular coupling would more accurately describe the nature of neural systems. Greater knowledge on the association and interface of brain and body via isomorphic physiologic counterparts to mind may carry profound implications in understanding intrinsic activity of the brain, consciousness, mind, and mental illness.

基于独立成分分析重症肌无力患者的静息态默认网络的功能连接改变及其与认知障碍的相关性

目的研究重症肌无力(myasthenia gravis,MG)患者大脑默认网络(default mode network,DMN)功能连接的改变,以及DMN和认知功能的关系。方法前瞻性纳入2020年1月至2022年12月就诊于苏州大学附属第一医院神经内科的MG患者39例,另选取同期性别、年龄、受教育年限、种族与MG患者匹配的40名健康志愿者作为健康对照组。对所有受试者进行神经心理学测试、情绪评估及静息态磁共振功能扫描。采用独立成分分析技术评估受试者大脑DMN的功能连接变化。采用Spearman相关性分析MG患者差异脑区的DMN的功能连接值与认知功能的相关性。结果MG组整体认知功能〔简易精神状态量表(MMSE)和蒙特利尔认知评估量表(MoCA)评分〕、言语学习和记忆能力(Rey听觉词语学习测验、词语流畅性测试)、视空间功能(钟表测试)评分均较对照组降低(均P<0.01);在执行能力测试方面,MG组连线功能测试完成时间长于对照组(P<0.01);MG组汉密尔顿焦虑量表和汉密尔顿抑郁量表评分均高于对照组(P<0.01)。独立成分分析结果显示,MG患者的DMN内功能连接在左后扣带回比对照组减弱(P<0.05,经过FDR校正)。MG患者的DMN内左后扣带回功能连接值与MMSE评分、数字符号转换测验评分呈正相关(P<0.05),而与连线测验A和B时间呈负相关(P<0.05)。结论MG患者在整体认知功能、言语学习和记忆力、视空间功能和执行功能方面下降,在左后扣带回的DMN内功能连接减弱,差异脑区在DMN内功能连接值与认知评分存在相关性,提示MG患者的认知功能损害可能与中枢神经系统受累有关。

静息态功能磁共振成像在血管性认知障碍患者默认网络研究中的应用进展

血管性认知障碍是由脑血管疾病导致的一种从轻度认知功能障碍至痴呆的综合征,由于缺乏敏感性和特异性生物标志物,早期不易鉴别和诊断。血管性认知障碍患者脑网络连接异常的脑区多位于默认网络,其异常变化的功能连接与患者的认知障碍程度相关。静息态功能磁共振成像技术是一种常用的检测静息态大脑内在活动的方法,应用静息态磁共振不同分析技术探索血管性认知障碍患者默认网络异常变化有助于深入研究血管性认知障碍的发病机制,并提供客观的影像依据。该文主要综述静息态功能磁共振成像技术在血管性认知障碍患者默认网络研究中的应用成果,为血管性认知障碍的精准诊断和评估提供新思路。

伴有童年创伤的重症抑郁患者异常全脑功能连接:一项静息态功能磁共振研究

【目的】童年创伤(CT)被认为是成年后发展为重度抑郁(MDD)的主要危险因素之一。然而,伴有CT的MDD(CT-MDD)患者的神经基础仍然知之甚少。因此,本研究的目的是探讨CT-MDD患者静息态全脑功能连接(FC)。【方法】对34名CT-MDD患者和34名健康对照组进行静息态功能磁共振扫描。进行全脑体素水平度中心性(DC)分析,选取两组间显著差异的脑区作为感兴趣区(ROI),进一步计算全脑FC。随后,将异常脑区DC,FC值与临床量表进行相关性分析。【结果】CT-MDD组右侧额中回(MFG)的DC值高于健康对照组。基于种子点的脑功能连接分析发现,与健康对照组相比,CT-MDD组右侧MFG与右内侧前额叶和左侧楔前叶之间的FC增加(P<0.05)。此外,右侧MFG的DC值与CT严重程度相关。【结论】我们的结果表明,以右侧MFG作为ROI,其与默认网络(DMN)中的两个重要脑区右内侧前额叶和左侧楔前叶之间的FC增加,这可能表明CT-MDD患者的认知执行网络与DMN之间的同步性增加。这些发现可能为深入了解CT-MDD的病理生理机制提供了见解。

基于脏气法时论辨治大脑默认网络功能损害

通过探讨大脑默认网络功能损害的病理机制与脏藏精功能受损的相关性,揭示脏藏精功能受损是原发性失眠的病机核心,并基于《素问·脏气法时论》“病-脏-药”三位一体的“气味合和”理论,以心、肝、脾三脏功能失衡为内核,探究大脑默认网络功能损害的中医证治,以期为临床防治原发性失眠大脑默认网络功能损害探索新思路。

重型抑郁障碍患者默认网络静态与动态功能连接变化

目的 基于静息态功能MRI(rs-fMRI)观察重型抑郁障碍(MDD)患者默认网络(DMN)静态与动态功能连接变化。方法 回顾性分析55例MDD患者(MDD组)及35名健康体检者(对照组)头颅高分辨率结构图像及rs-fMRI;以Matlab平台CONN工具箱进行图像预处理及独立成分分析(ICA)以提取DMN;比较组间DMN与全脑静态与动态功能连接变化;采用Pearson相关性分析观察MDD组与对照组存在差异脑区DMN与汉密尔顿抑郁量表-24项(HAMD-24)、汉密尔顿焦虑量表(HAMA)及韦氏智力测验评分的相关性。结果 相比对照组,MDD组DMN与丘脑、楔前叶及中央前回静态功能连接均减弱(P均<0.05);MDD组DMN与丘脑功能连接强度与HAMD-24评分呈低度负相关(r=-0.333,P=0.014)。相比对照组,MDD组DMN内侧前额叶皮层、左/右外侧顶叶与伏隔核,以及左外侧顶叶、后扣带回与丘脑动态功能连接均减弱。MDD组DMN内侧前额叶皮层-伏隔核、后扣带回-丘脑动态功能连接强度与HAMD-24评分呈低度正相关(r=0.313,P=0.019;r=0.311,P=0.021)。结论 MDD患者DMN与局部脑区存在静态与动态连接异常,部分与抑郁症严重程度相关。

阿尔茨海默病风险人群的超早期β淀粉样蛋白沉积与默认网络模式的关联研究

目的 探讨阿尔茨海默病风险人群的超早期脑脊液β淀粉样蛋白(Aβ)沉积与默认网络(DMN)功能连通性的关系。方法 纳入阿尔茨海默病神经影像学计划从2010年7月至2018年12月在北美地区招募的轻度认知障碍受试者,根据36个月随访期脑脊液Aβ的变化将受试者分为Aβ下降组(25例)和稳定组(19例)。运用脑功能MRI技术研究脑脊液Aβ下降、DMN功能连通性和认知功能变化的关系。结果 相较于Aβ稳定组,Aβ下降组在随访过程中连线测试-B(TMT-B)时间延长(P<0.05)。在双侧枕中回和左侧颞中回,Aβ下降组DMN功能连通性低于Aβ稳定组(P<0.01);其中,左侧颞中回的功能连通性与TMT-B时间呈负相关(r<0,P<0.05)。结论 超早期Aβ沉积与颞枕叶DMN功能连通性下降密切相关,且导致了执行功能损害。

基于部分定向相干的帕金森病默认模式网络脑电分析

目的:为了分析帕金森病患者大脑的默认模式网络(default mode network,DMN)潜在变化的原因和其临床特点的关系,以及探讨如何提取其脑电信号特征并对其进行准确有效地分类.方法:选择帕金森病患者和健康对照组各26名被试作为实验对象,将部分定向相干(partial directed coherence,PDC)应用于DMN相关电极的数据序列,获得对照组和帕金森病受试者的有效连接.通过统计分析后,得出6条具有显著差异的PDC连接,对它们进行深入讨论.进一步地,将这些连接值组成特征集并进行分类.结果:与对照组相比,帕金森病患者中有关注意力控制之间的连接降低,在涉及有关工作记忆的连接中,帕金森病相比于健康组患者的一些连接都有不同程度的增加.同时,使用XGBoost算法对特征集进行分类,得到76.5%的平均测试准确率.结论:静息状态下帕金森病患者的非运动症状与DMN网络存在显著性的关系,表现在注意力控制与记忆功能上,这与DMN中BA区的受损有很大的关系.随后对两类受试者的分类也验证了PDC算法用于DMN分析的有效性,为帕金森病人的测试和预防提供了一种新途径.

肝豆状核变性患者默认模式网络变化及模型构建

目的:基于独立成分分析(ICA),探讨肝豆状核变性(WD)患者默认模式网络(DMN)功能连接(FC)的改变及其与临床神经精神特征之间的关系。方法:将2021年1月-2021年12月在本院就诊的85例肝豆状核变性患者和年龄、性别相匹配的85例健康志愿者(HC组)纳入本研究。对每例被试采用统一肝豆状核变性评分量表(UWDRS)进行评估,包括神经功能症状(UWDRS-N)和精神症状(UWDRS-P)评分,并根据UWDRS评分将患者分为神经精神症状重度组(>10分)和轻度组(≤10分)。使用3.0T磁共振BOLD序列采集静息态fMRI数据,采用ICA方法提取DMN内各体素的FC值,并在HC组与WD组之间进行比较,对有差异脑区的FC值与临床量表评分进行Pearson相关性分析。以DMN内所有体素的FC值为特征变量采用支持向量机(SVM)的方法构建分类模型,包括正常组与WD组以及轻度与重度WD组。结果:与对照组比较,WD组的DMN内表现出广泛的FC值减低,包括前默认模式网络(aDMN)内的左内侧前额叶皮层(L_MPFC)和左侧前扣带回(L_ACC),以及后DMN(pDMN)内的左侧角回(L_ANG)、楔前叶(PCUN)、左侧顶下小叶(L_IPG)和左侧后扣带回(L_PCC)。aDMN内的L_MPFC、L_ACC和pDMN内的PCUN的FC值与UWDRS-N评分呈负相关,aDMN内的L_MPFC、L_PCC和pDMN内的L_IPG的FC值与UWDRS-P评分呈负相关。采用SVM构建的二分类器,在鉴别WD与HC组时的符合率为80.23%,AUC为0.865;在鉴别轻度与重度WD组的符合率为70.89%,AUC为0.723。结论:WD患者的默认模式网络中存在广泛的功能连接减低,其可能是导致患者出现神经精神症状(如高阶认知障碍)的潜在神经病理机制。基于DMN的FC值构建的SVM分类器可提高对WD疾病及其病情转归的评估效能。

基于LSTM和多头注意力机制的企业违约预测模型

违约预测是指用企业过去时刻的数据和违约状态预测企业未来的违约概率。违约预测对股票投资、债券投资和银行贷款等具有极为重要的意义。本研究涉及两个科学问题:一是如何使用连续多年的企业数据预测企业违约概率;二是研究输入模型的每个时间窗口对违约预测状态的影响程度。用LSTM网络建立违约预测模型,用连续多年的企业数据预测违约概率,改变了违约预测建模时只用一个时间窗口预测违约概率的现状,并首次将多头注意力机制应用于违约预测模型,探索每个时间窗口对违约预测值的影响程度,避免了现有模型只做预测不揭示时间窗口对违约预测影响程度的弊端。研究表明:一是在违约预测建模时考虑企业数据的时序性更合理且会提升模型预测精度;二是违约预测的最佳时间窗口个数可以是5到10之间的数,总体上时间窗口越多违约预测精度越高;三是本文搭建的违约预测模型框架有效减少了违约预测结果的第2类错误,降低了坏客户被预测为好客户的风险。

基于事件触发机制和最小学习参数的FAHV指定时间收敛自适应控制

针对当前吸气式高超声速飞行器自适应控制结果仅能实现误差渐近收敛于预设包络、神经权值在线更新存在计算爆炸、对机载资源过度占用的难题,提出了基于事件触发机制和最小学习参数的FAHV指定时间收敛自适应控制方法。首先,阐述了一种不依赖精确误差初值同时又能确保误差指定时间收敛的改进预设性能控制机制;其次,构建了用于FAHV干扰辨识的相对阈值事件触发神经网络;最后,设计了相对阈值事件触发控制算法,有效降低了闭环控制器对通信资源的消耗,在非等周期信号传输的基础上实现了良好的控制精度。仿真结果表明,所提方法能够在低计算与传输资源消耗下对高度/速度参考信号实施指定时间跟踪。

The Dynamic Relationship of Brain Networks Across Time Windows During Product-Based Creative Thinking

Consensus of creativity research suggests that the measurement of both originality and valuableness is necessary when designing creativity tasks.However,few studies have emphasized valuableness when exploring underlying neural substrates of creative thinking.The present study employs product-based creativity tasks that measure both originality and valuableness in an exploration of the dynamic relationship between the default mode(DMN),executive control(ECN),and salience(SN)networks through time windows.This methodology highlights relevance,or valuableness,in creativity evaluation as opposed to divergent thinking tasks solely measuring originality.The researchers identified seven brain regions belonging to the ECN,DMN,and SN as regions of interest(ROIs),as well as four representative seeds to analyze functional connectivity in 25 college student participants.Results showed that all of the identified ROIs were involved during the creative task.The insula,precuneus,and ventrolateral prefrontal cortex(vlPFC)remained active across all stages of product-based creative thinking.Moreover,the connectivity analyses revealed varied interaction patterns of DMN,ECN,and SN at different thinking stages.The integrated findings of the whole brain,ROI,and connectivity analyses suggest a trend that the DMN and SN(which relate to bottom-up thinking)attenuate as time proceeds,whereas the vlPFC(which relates to top-down thinking)gets stronger at later stages;these findings reflect the nature of our creativity tasks and decision-making of valuableness in later stages.Based on brain region activation throughout execution of the task,we propose that product-based creative process may include three stages:exploration and association,incubation and insight,and finally,evaluation and decision making.This model provides a thinking frame for further research and classroom instruction.

工控网络安全新兴理念及发展态势分析

随着数字技术的泛在化和网络攻击的与日俱增,加之AI和量子计算等颠覆性技术开始应用,常规网络安全防护理念及技术已不能满足新形势下关键基础设施工控网络安全的需求。本文描述了九位一体安全深度防护、设计安全、默认安全等新兴安全理念的概念、模型结构、特性及应用,并简要分析了边缘计算、AI、量子计算、分布式账簿、去中心化网络安全管理等新兴技术方面的发展态势。

基于rs-fMRI对遗忘型轻度认知功能障碍患者脑默认网络改变的研究

目目的的:探索遗忘型轻度认知功能障碍(aMCI)患者静息态默认网络(DMN)内功能连接(FC)改变及其与认知功能的关系。方法:根据纳入标准和排除标准,对40例未经治疗的aMCI患者(aMCI组)及40例认知功能正常的志愿者(对照组)行静息态功能磁共振成像(rs-fMRI)检查,对照组的性别、年龄、受教育年限与aMCI组相匹配。应用独立成分分析(ICA)方法提取2组受试者的DMN,并用SPM 12软件比较2组间DMN内FC差异,同时应用Pearson或Spearman相关性分析验证aMCI组差异脑区zFC值与神经心理学评分的相关性。结果:与对照组比较,aMCI组FC增强脑区位于右侧海马旁回、左侧岛叶、左侧扣带回后部、左侧楔叶、右侧岛盖部额下回、左侧缘上回、左侧楔前叶及右侧中央前回;FC减弱脑区位于左侧额中回、右侧缘上回、右侧扣带回前部、右侧角回及颞中回。相关性分析显示,aMCI组左侧额中回(r=0.439,P=0.005)、右侧颞中回(r=0.422,P=0.007)、右侧海马旁回(r=0.468,P=0.002)及左侧楔前叶zFC值(r=0.482,P=0.002)与MMSE评分呈正相关;右侧扣带回前部zFC值与AVLT延迟记忆评分(r=0.362,P=0.022)、DST顺背评分(r=0.503,P=0.001)呈正相关;右侧中央前回zFC值与TMT-B评分(r=-0.450,P=0.004)呈负相关。结论论:aMCI患者DMN内发生FC异常改变与记忆力、注意力、执行功能及视听功能缺陷相关,推测DMN内FC改变可能成为早期识别和诊断AD的影像学生物指标。