Synthetic aperture radars(SARs)encounter the azimuth cutoff problem when observing sea waves.Consequently,SARs can only capture the waves with wavelengths larger than the cutoff wavelength and lose the information of ...Synthetic aperture radars(SARs)encounter the azimuth cutoff problem when observing sea waves.Consequently,SARs can only capture the waves with wavelengths larger than the cutoff wavelength and lose the information of waves with smaller wavelengths.To increase the accuracy of SAR wave observations,this paper investigates an azimuth cutoff compensation method based on the simulated multiview SAR wave synchronization data obtained by the collaborative observation via networked satellites.Based on the simulated data and the equivalent multiview measured data from Sentinel-1 virtual networking,the method is verified and the cutoff wavelengths decrease by 16.40%and 14.00%.The biases of the inversion significant wave height with true values decrease by 0.04 m and 0.14 m,and the biases of the mean wave period decrease by 0.17 s and 0.22 s,respectively.These results demonstrate the effectiveness of the azimuth cutoff compensation method.Based on the azimuth cutoff compensation method,the multisatellite SAR networking mode for wave observations are discussed.The highest compensation effect is obtained when the combination of azimuth angle is(95°,115°,135°),the orbital intersection angle is(50°,50°),and three or four satellites are used.The study of the multisatellite networking mode in this paper can provide valuable references for the compensation of azimuth cutoff and the observation of waves by a multisatellite network.展开更多
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 attent...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.展开更多
Medical procedures are inherently invasive and carry the risk of inducing pain to the mind and body.Recently,efforts have been made to alleviate the discomfort associated with invasive medical procedures through the u...Medical procedures are inherently invasive and carry the risk of inducing pain to the mind and body.Recently,efforts have been made to alleviate the discomfort associated with invasive medical procedures through the use of virtual reality(VR)technology.VR has been demonstrated to be an effective treatment for pain associated with medical procedures,as well as for chronic pain conditions for which no effective treatment has been established.The precise mechanism by which the diversion from reality facilitated by VR contributes to the diminution of pain and anxiety has yet to be elucidated.However,the provision of positive images through VR-based visual stimulation may enhance the functionality of brain networks.The salience network is diminished,while the default mode network is enhanced.Additionally,the medial prefrontal cortex may establish a stronger connection with the default mode network,which could result in a reduction of pain and anxiety.Further research into the potential of VR technology to alleviate pain could lead to a reduction in the number of individuals who overdose on painkillers and contribute to positive change in the medical field.展开更多
BACKGROUND Currently,adolescent depression is one of the most significant public health concerns,markedly influencing emotional,cognitive,and social maturation.Despite advancements in distinguish the neurobiological s...BACKGROUND Currently,adolescent depression is one of the most significant public health concerns,markedly influencing emotional,cognitive,and social maturation.Despite advancements in distinguish the neurobiological substrates underlying depression,the intricate patterns of disrupted brain network connectivity in adolescents warrant further exploration.AIM To elucidate the neural correlates of adolescent depression by examining brain network connectivity using resting-state functional magnetic resonance imaging(rs-fMRI).METHODS The study cohort comprised 74 depressed adolescents and 59 healthy controls aged 12 to 17 years.Participants underwent rs-fMRI to evaluate functional connectivity within and across critical brain networks,including the visual,default mode network(DMN),dorsal attention,salience,somatomotor,and frontoparietal control networks.RESULTS Analyses revealed pronounced functional disparities within key neural circuits among adolescents with depression.The results demonstrated existence of hemispheric asymmetries characterized by enhanced activity in the left visual network,which contrasted the diminished activity in the right hemisphere.The DMN facilitated increased activity within the left prefrontal cortex and reduced engagement in the right hemisphere,implicating disrupted self-referential and emotional processing mechanisms.Additionally,an overactive right dorsal attention network and a hypoactive salience network were identified,underscoring significant abnormalities in attentional and emotional regulation in adolescent depression.CONCLUSION The findings from this study underscore distinct neural connectivity disruptions in adolescent depression,underscoring the critical role of specific neurobiological markers for precise early diagnosis of adolescent depression.The observed functional asymmetries and network-specific deviations elucidate the complex neurobiological architecture of adolescent depression,supporting the development of targeted therapeutic strategies.展开更多
BACKGROUND Group cognitive behavioral therapy(GCBT)is increasingly being used to treat obsessive-compulsive disorder(OCD)because of its high efficiency,economy,and interaction among group members.However,the changes i...BACKGROUND Group cognitive behavioral therapy(GCBT)is increasingly being used to treat obsessive-compulsive disorder(OCD)because of its high efficiency,economy,and interaction among group members.However,the changes in network functional connectivity(FC)in patients with OCD with GCBT remain unclear.AIM To investigate inter-and intra-network resting-state FC(rs-FC)abnormalities before and after GCBT in unmedicated patients with OCD and validate the efficacy of GCBT.METHODS Overall,33 individuals with OCD and 26 healthy controls underwent resting-state functional magnetic resonance imaging.The patients were rescanned 12 weeks after GCBT.Four cognition-related networks-default mode network(DMN),dorsal attention network(DAN),salience network(SAN),and frontoparietal network(FPN)-were selected to examine FC abnormalities within and between OCD networks before and after GCBT.Neuropsychological assessments including memory,executive function,speech,attention,and visuospatial ability were reassessed following GCBT.Pearson’s correlations were used to analyze the relationship between aberrant FC in cognition-related networks and altered neuropsychological assessments in patients.RESULTS Rs-FC within the DMN and DAN decreased significantly.Additionally,rs-FC between the DMN-DAN,DMNFPN,DMN-SAN,and DAN-SAN also decreased.Significant improvements were observed in cognitive functions,such as memory,executive function,attention,and visuospatial ability.Furthermore,reduced rs-FC within the DMN correlated with visuospatial ability and executive function;DAN positively correlated with Shape Trails Test(STT)-A test elapsed time;DMN-DAN negatively correlated with Rey-Osterrieth Complex Figure(Rey-O)mimicry time and the three elapsed times of the tower of Hanoi;DMN-SAN negatively correlated with Rey-O imitation time and positively correlated with STT-A test elapsed time;and DMN-FPN negatively correlated with Auditory Word Learning Test N1 and N4 scores.CONCLUSION Decreased rs-FC within the DMN and DAN,which correlated with executive function post-treatment,has potential as a neuroimaging marker to predict treatment response to GCBT in patients with OCD.展开更多
Background The heterogeneity of depression limits the treatment outcomes of intermittent theta burst stimulation(iTBS)and hinders the identification of predictive factors.This study investigated functional network con...Background The heterogeneity of depression limits the treatment outcomes of intermittent theta burst stimulation(iTBS)and hinders the identification of predictive factors.This study investigated functional network connectivity and predictors of iTBS treatment outcomes in adolescents and young adults with depression.Aim This study aimed to identify default mode network(DMN)-based connectivity patterns associated with varying iTBS treatment outcomes in depression.Methods Data from a randomised controlled trial of iTBS in depression(n=82)were analysed using a data-driven approach to classify homogeneous subgroups based on the DMN.Connectivity subgroups were compared on depressive symptoms and cognitive function at pretreatment and post-treatment.Furthermore,the predictive significance of baseline inflammatory cytokines on post-treatment outcomes was evaluated.Results Two distinct subgroups were identified.Subgroup 1 exhibited high heterogeneity and greater centrality in the posterior cingulate cortex and retrosplenial cortex,while subgroup 2 showed more homogeneous connectivity patterns and greater centrality in the temporoparietal junction and posterior inferior parietal lobule.No main effect for subgroup,treatment or subgroup×treatment interaction was revealed in the improvement of depressive symptoms.A significant subgroup×treatment interaction related to symbol coding improvement was detected(F=5.22,p=0.026).Within subgroup 1,the active group showed significantly greater improvement in symbol coding compared with the sham group(t=2.30,p=0.028),while baseline levels of interleukin-6 and C-reactive protein emerged as significant indicators for predicting improvements in symbolic coding(R2=0.35,RMSE(root-mean-square error)=5.72,p=0.013).Subgroup 2 showed no significant findings in terms of cognitive improvement or inflammatory cytokines predictions.展开更多
Schizophrenia is a severe mental disorder characterized by impaired perception, delusions, thought disorder, abnormal emotion regulation, altered motor function, and impaired drive. The default mode network （DMN）, s...Schizophrenia is a severe mental disorder characterized by impaired perception, delusions, thought disorder, abnormal emotion regulation, altered motor function, and impaired drive. The default mode network （DMN）, since it was first proposed in 2001, has become a central research theme in neuropsychiatric disorders, including schizophrenia. In this review, first we define the DMN and describe its functional activity, functional and anatomical connectivity, heritability, and inverse correlation with the task positive network. Second, we review empirical studies of the anatomical and functional DMN, and anti-correlation between DMN and the task positive network in schizophrenia. Finally, we review preliminary evidence about the relationship between antipsychotic medications and regulation of the DMN, review the role of DMN as a treatment biomarker for this disease, and consider the DMN effects of individualized therapies for schizophrenia.展开更多
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)patie...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.展开更多
The purpose of this study was to explore the differences in interhemispheric functional connectivity in patients with Alzheimer’s disease(AD) and amnestic mild cognitive impairment(aMCI) based on a triple network mod...The purpose of this study was to explore the differences in interhemispheric functional connectivity in patients with Alzheimer’s disease(AD) and amnestic mild cognitive impairment(aMCI) based on a triple network model consisting of the default mode network(DMN), salience network(SN), and executive control network(ECN). The technique of voxel-mirrored homotopic connectivity(VMHC) analysis was applied to explore the aberrant connectivity of all patients. The results showed that:(1) the statistically significant connections of interhemispheric brain regions included DMN-related brain regions(i.e. precuneus, calcarine, fusiform, cuneus, lingual gyrus, temporal inferior gyrus, and hippocampus), SN-related brain regions(i.e. frontoinsular cortex), and ECN-related brain regions(i.e. frontal middle gyrus and frontal inferior);(2) the precuneus and frontal middle gyrus in the AD group exhibited lower VMHC values than those in the aMCI and healthy control(HC) groups, but no significant difference was observed between the a MCI and HC groups; and(3) significant correlations were found between peak VMHC results from the precuneus and Mini Mental State Examination(MMSE) and Montreal Cognitive Scale(MOCA) scores and their factor scores in the AD, a MCI, and AD plus aMCI groups, and between the results from the frontal middle gyrus and MOCA factor scores in the a MCI group. These findings indicated that impaired interhemispheric functional connectivity was observed in AD and could be a sensitive neuroimaging biomarker for AD. More specifically, the DMN was inhibited, while the SN and ECN were excited. VMHC results were correlated with MMSE and MOCA scores, highlighting that VMHC could be a sensitive neuroimaging biomarker for AD and the progression from aMCI to AD.展开更多
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...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.展开更多
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 cont...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.展开更多
Previous studies revealed that the error of pole coordinate prediction will significantly increase for a prediction period longer than 100 days, and this is mainly caused by short period oscillations. Empirical mode d...Previous studies revealed that the error of pole coordinate prediction will significantly increase for a prediction period longer than 100 days, and this is mainly caused by short period oscillations. Empirical mode decomposition （EMD）, which is increasingly popular and has advantages over classical wavelet decomposition, can be used to remove short period variations from observed time series of pole co- ordinates. A hybrid model combing EMD and extreme learning machine （ELM）, where high frequency signals are removed and processed time series is then modeled and predicted, is summarized in this paper. The prediction performance of the hybrid model is compared with that of the ELM-only method created from original time series. The results show that the proposed hybrid model outperforms the pure ELM method for both short-term and long-term prediction of pole coordinates. The improvement of prediction accuracy up to 360 days in the future is found to be 24.91% and 26.79% on average in terms of mean absolute error （MAE） for the xp and yp components of pole coordinates, respectively.展开更多
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 chang...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.展开更多
The provision mode of the telecommunication service has experienced an evolving process, and showing the developing trend from distributed to centralized, from integrated to separated, and from closed to open. To suit...The provision mode of the telecommunication service has experienced an evolving process, and showing the developing trend from distributed to centralized, from integrated to separated, and from closed to open. To suit this trend, there will be three provision modes as Session Initiation Protocol (SIP) server, Open Service Access (OSA) application server and intelligent network(IN) in Next Generation Network (NGN), provides all kinds of services and applications to the subscribers. With the popularity of broadband access and Internet, the NGN will provide single telecommunication service and act as the important national infrastructure to offer various information services to the subscribers. The service provision mode will be more open, diversified, and individualized.展开更多
Localizing network legal supervision based on national conditions, legal traditions and the needs of economic and political development is the basis to manage and administrate the network by law. Adjusted to media con...Localizing network legal supervision based on national conditions, legal traditions and the needs of economic and political development is the basis to manage and administrate the network by law. Adjusted to media convergence and the needs of network cultural industry development, China has made the lawmaking of media transform from practical service oriented management to functional oriented management of media. This strategy aims to prevent network medium risk effectively according to network communication regularity.展开更多
In this paper, an extended Kendall model for the priority scheduling input-line group output with multi-channel in Asynchronous Transfer Mode （ATM） exchange system is proposed and then the mean method is used to mod...In this paper, an extended Kendall model for the priority scheduling input-line group output with multi-channel in Asynchronous Transfer Mode （ATM） exchange system is proposed and then the mean method is used to model mathematically the non-typical non-anticipative PRiority service （PR） model. Compared with the typical and non-anticipative PR model, it expresses the characteristics of the priority scheduling input-line group output with multi-channel in ATM exchange system. The simulation experiment shows that this model can improve the HOL block and the performance of input-queued ATM switch network dramatically. This model has a better developing prospect in ATM exchange system.展开更多
Objective： To investigate functional connectivity within default mode network （DMN） and ex-ecutive control network （ECN） in vascular cognitive im-pairment, no dementia （VCIND）. Methods： Twenty-eight VCIND pati...Objective： To investigate functional connectivity within default mode network （DMN） and ex-ecutive control network （ECN） in vascular cognitive im-pairment, no dementia （VCIND）. Methods： Twenty-eight VCIND patients and sixteen healthy controls were recruit-ed. A seed-based connectivity analysis was performed us-ing data from resting-state functional magnetic resonance imaging （fMRI）. Based on previous fndings, posteriorcingulate cortex （PCC） and dorsolateral prefrontal cortex （DLPFC） were chosen as regions of interest to study these networks.One-sample t-test and two-sample t-test were used for statistical analysis. Results： Compared with thecontrols, the VCIND group exhibited increased functional activity in such DMN regions as the left inferior temporal gyrus, parahippocampal gyrus, and medial frontal gyrus. The VCIND group had decreased functional connectivity of DMN at right superior frontal gyrus, left mid-cingu-late area, the medial part of left superior frontal gyrus, and bilateral medial frontal gyrus. The VCIND group also showed decreased functional connectivity of ECN pri-marilyat left inferior parietal gyrus, right angular gyrus, right middle occipital gyrus, and right middle frontal cor-tex. Conclusions： Increased functional connectivity with-in DMN and decreased functional connectivity within ECN suggested dysfunction of these two networks, which mightbe associated with the cognitive defcitsin patients with VCIND. These fndingsmay help usunderstandthe pathogenesis and clinical characteristics of VCIND.展开更多
Neuroimaging techniques such as functional magnetic resonance imaging and positron emission tomography have provided an unprecedented neurobiological perspective for research on personality traits. Evidence from task-...Neuroimaging techniques such as functional magnetic resonance imaging and positron emission tomography have provided an unprecedented neurobiological perspective for research on personality traits. Evidence from task-related neuroimaging has shown that extraversion is associated with activations in regions of the anterior cingulate cortex, dorsolateral prefrontal cortex, middle temporal gyrus and the amygdala. Currently, resting-state neuroimaging is being widely used in cognitive neuroscience. Initial exploration of extraversion has revealed correlations with the medial prefrontal cortex, anterior cingulate cortex, insular cortex, and the precuneus. Recent research work has indicated that the long-range temporal dependence of the resting-state spontaneous oscillation has high test-retest reliability. Moreover, the long-range temporal dependence of the resting-state networks is highly correlated with personality traits, and this can be used for the prediction of extraversion. As the long-range temporal dependence reflects real-time information updating in individuals, this method may provide a new approach to research on personality traits.展开更多
Numerous studies have shown abnormal brain functional connectivity in individuals with Alzheimer’s disease(AD)or amnestic mild cognitive impairment(aMCI).However,most studies examined traditional resting state functi...Numerous studies have shown abnormal brain functional connectivity in individuals with Alzheimer’s disease(AD)or amnestic mild cognitive impairment(aMCI).However,most studies examined traditional resting state functional connections,ignoring the instantaneous connection mode of the whole brain.In this case-control study,we used a new method called dynamic functional connectivity(DFC)to look for abnormalities in patients with AD and aMCI.We calculated dynamic functional connectivity strength from functional magnetic resonance imaging data for each participant,and then used a support vector machine to classify AD patients and normal controls.Finally,we highlighted brain regions and brain networks that made the largest contributions to the classification.We found differences in dynamic function connectivity strength in the left precuneus,default mode network,and dorsal attention network among normal controls,aMCI patients,and AD patients.These abnormalities are potential imaging markers for the early diagnosis of AD.展开更多
Traumatic brain injury survivors often experience cognitive deficits and neuropsychiatric symptoms.However,the neurobiological mechanisms underlying specific impairments are not fully understood.Advances in neuroimagi...Traumatic brain injury survivors often experience cognitive deficits and neuropsychiatric symptoms.However,the neurobiological mechanisms underlying specific impairments are not fully understood.Advances in neuroimaging techniques（such as diffusion tensor imaging and functional MRI）have given us new insights on structural and functional connectivity patterns of the human brain in both health and disease.The connectome derived from connectivity maps reflects the entire constellation of distributed brain networks.Using these powerful neuroimaging approaches,changes at the microstructural level can be detected through regional and global properties of neuronal networks.Here we will review recent developments in the study of brain network abnormalities in traumatic brain injury,mainly focusing on structural and functional connectivity.Some connectomic studies have provided interesting insights into the neurological dysfunction that occurs following traumatic brain injury.These techniques could eventually be helpful in developing imaging biomarkers of cognitive and neurobehavioral sequelae,as well as predicting outcome and prognosis.展开更多
基金the support of the National Natural Science Foundation of China(No.61931025)the National Key R&D Program of China(No.2017YFC1405600)。
文摘Synthetic aperture radars(SARs)encounter the azimuth cutoff problem when observing sea waves.Consequently,SARs can only capture the waves with wavelengths larger than the cutoff wavelength and lose the information of waves with smaller wavelengths.To increase the accuracy of SAR wave observations,this paper investigates an azimuth cutoff compensation method based on the simulated multiview SAR wave synchronization data obtained by the collaborative observation via networked satellites.Based on the simulated data and the equivalent multiview measured data from Sentinel-1 virtual networking,the method is verified and the cutoff wavelengths decrease by 16.40%and 14.00%.The biases of the inversion significant wave height with true values decrease by 0.04 m and 0.14 m,and the biases of the mean wave period decrease by 0.17 s and 0.22 s,respectively.These results demonstrate the effectiveness of the azimuth cutoff compensation method.Based on the azimuth cutoff compensation method,the multisatellite SAR networking mode for wave observations are discussed.The highest compensation effect is obtained when the combination of azimuth angle is(95°,115°,135°),the orbital intersection angle is(50°,50°),and three or four satellites are used.The study of the multisatellite networking mode in this paper can provide valuable references for the compensation of azimuth cutoff and the observation of waves by a multisatellite network.
文摘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.
文摘Medical procedures are inherently invasive and carry the risk of inducing pain to the mind and body.Recently,efforts have been made to alleviate the discomfort associated with invasive medical procedures through the use of virtual reality(VR)technology.VR has been demonstrated to be an effective treatment for pain associated with medical procedures,as well as for chronic pain conditions for which no effective treatment has been established.The precise mechanism by which the diversion from reality facilitated by VR contributes to the diminution of pain and anxiety has yet to be elucidated.However,the provision of positive images through VR-based visual stimulation may enhance the functionality of brain networks.The salience network is diminished,while the default mode network is enhanced.Additionally,the medial prefrontal cortex may establish a stronger connection with the default mode network,which could result in a reduction of pain and anxiety.Further research into the potential of VR technology to alleviate pain could lead to a reduction in the number of individuals who overdose on painkillers and contribute to positive change in the medical field.
基金Supported by the Medical Research Project of the Chongqing Municipal Health Commission,No.2024WSJK110.
文摘BACKGROUND Currently,adolescent depression is one of the most significant public health concerns,markedly influencing emotional,cognitive,and social maturation.Despite advancements in distinguish the neurobiological substrates underlying depression,the intricate patterns of disrupted brain network connectivity in adolescents warrant further exploration.AIM To elucidate the neural correlates of adolescent depression by examining brain network connectivity using resting-state functional magnetic resonance imaging(rs-fMRI).METHODS The study cohort comprised 74 depressed adolescents and 59 healthy controls aged 12 to 17 years.Participants underwent rs-fMRI to evaluate functional connectivity within and across critical brain networks,including the visual,default mode network(DMN),dorsal attention,salience,somatomotor,and frontoparietal control networks.RESULTS Analyses revealed pronounced functional disparities within key neural circuits among adolescents with depression.The results demonstrated existence of hemispheric asymmetries characterized by enhanced activity in the left visual network,which contrasted the diminished activity in the right hemisphere.The DMN facilitated increased activity within the left prefrontal cortex and reduced engagement in the right hemisphere,implicating disrupted self-referential and emotional processing mechanisms.Additionally,an overactive right dorsal attention network and a hypoactive salience network were identified,underscoring significant abnormalities in attentional and emotional regulation in adolescent depression.CONCLUSION The findings from this study underscore distinct neural connectivity disruptions in adolescent depression,underscoring the critical role of specific neurobiological markers for precise early diagnosis of adolescent depression.The observed functional asymmetries and network-specific deviations elucidate the complex neurobiological architecture of adolescent depression,supporting the development of targeted therapeutic strategies.
基金Supported by the Pharmaceutical Science and Technology Project of Zhejiang Province,No.2023RC266the Natural Science Foundation of Ningbo,No.202003N4266.
文摘BACKGROUND Group cognitive behavioral therapy(GCBT)is increasingly being used to treat obsessive-compulsive disorder(OCD)because of its high efficiency,economy,and interaction among group members.However,the changes in network functional connectivity(FC)in patients with OCD with GCBT remain unclear.AIM To investigate inter-and intra-network resting-state FC(rs-FC)abnormalities before and after GCBT in unmedicated patients with OCD and validate the efficacy of GCBT.METHODS Overall,33 individuals with OCD and 26 healthy controls underwent resting-state functional magnetic resonance imaging.The patients were rescanned 12 weeks after GCBT.Four cognition-related networks-default mode network(DMN),dorsal attention network(DAN),salience network(SAN),and frontoparietal network(FPN)-were selected to examine FC abnormalities within and between OCD networks before and after GCBT.Neuropsychological assessments including memory,executive function,speech,attention,and visuospatial ability were reassessed following GCBT.Pearson’s correlations were used to analyze the relationship between aberrant FC in cognition-related networks and altered neuropsychological assessments in patients.RESULTS Rs-FC within the DMN and DAN decreased significantly.Additionally,rs-FC between the DMN-DAN,DMNFPN,DMN-SAN,and DAN-SAN also decreased.Significant improvements were observed in cognitive functions,such as memory,executive function,attention,and visuospatial ability.Furthermore,reduced rs-FC within the DMN correlated with visuospatial ability and executive function;DAN positively correlated with Shape Trails Test(STT)-A test elapsed time;DMN-DAN negatively correlated with Rey-Osterrieth Complex Figure(Rey-O)mimicry time and the three elapsed times of the tower of Hanoi;DMN-SAN negatively correlated with Rey-O imitation time and positively correlated with STT-A test elapsed time;and DMN-FPN negatively correlated with Auditory Word Learning Test N1 and N4 scores.CONCLUSION Decreased rs-FC within the DMN and DAN,which correlated with executive function post-treatment,has potential as a neuroimaging marker to predict treatment response to GCBT in patients with OCD.
基金supported by the Guangzhou Municipal Key Discipline in Medicine(2021-2023)the Guangzhou High-level Clinical Key Specialty,the Guangzhou Research-oriented Hospital,the Innovative Clinical Technique of Guangzhou(2024-2026)+6 种基金the Guangdong Basic and Applied Basic Research Foundation(grant number 2022A1515011567,2020A1515110565)the Guangzhou Science,Technology Planning Project(grant number 202201010714,202103000032)the National Natural Science Foundation of China(grant number 82471546)the Guangdong College Students Innovation and Entrepreneurship Training Project(grant number S202310570038)the Guangzhou Health Science and Technology Project(grant number 20231A010038)the Guangzhou Traditional Chinese Medicine and Integrated Traditional Chinese and Western Medicine Technology Project(grant number:20232A010013)the Science and Technology Plan Project of Guangzhou(2023A03J0842).
文摘Background The heterogeneity of depression limits the treatment outcomes of intermittent theta burst stimulation(iTBS)and hinders the identification of predictive factors.This study investigated functional network connectivity and predictors of iTBS treatment outcomes in adolescents and young adults with depression.Aim This study aimed to identify default mode network(DMN)-based connectivity patterns associated with varying iTBS treatment outcomes in depression.Methods Data from a randomised controlled trial of iTBS in depression(n=82)were analysed using a data-driven approach to classify homogeneous subgroups based on the DMN.Connectivity subgroups were compared on depressive symptoms and cognitive function at pretreatment and post-treatment.Furthermore,the predictive significance of baseline inflammatory cytokines on post-treatment outcomes was evaluated.Results Two distinct subgroups were identified.Subgroup 1 exhibited high heterogeneity and greater centrality in the posterior cingulate cortex and retrosplenial cortex,while subgroup 2 showed more homogeneous connectivity patterns and greater centrality in the temporoparietal junction and posterior inferior parietal lobule.No main effect for subgroup,treatment or subgroup×treatment interaction was revealed in the improvement of depressive symptoms.A significant subgroup×treatment interaction related to symbol coding improvement was detected(F=5.22,p=0.026).Within subgroup 1,the active group showed significantly greater improvement in symbol coding compared with the sham group(t=2.30,p=0.028),while baseline levels of interleukin-6 and C-reactive protein emerged as significant indicators for predicting improvements in symbolic coding(R2=0.35,RMSE(root-mean-square error)=5.72,p=0.013).Subgroup 2 showed no significant findings in terms of cognitive improvement or inflammatory cytokines predictions.
基金supported by the National Natural Science Foundation of China(81271484,81471361,30900486,and 81371480)the National Basic Research Development Program(973 Program)of China(2012CB517904)the Nation Sponsored Study Abroad Program from China Scholarship Council(201506370095)
文摘Schizophrenia is a severe mental disorder characterized by impaired perception, delusions, thought disorder, abnormal emotion regulation, altered motor function, and impaired drive. The default mode network （DMN）, since it was first proposed in 2001, has become a central research theme in neuropsychiatric disorders, including schizophrenia. In this review, first we define the DMN and describe its functional activity, functional and anatomical connectivity, heritability, and inverse correlation with the task positive network. Second, we review empirical studies of the anatomical and functional DMN, and anti-correlation between DMN and the task positive network in schizophrenia. Finally, we review preliminary evidence about the relationship between antipsychotic medications and regulation of the DMN, review the role of DMN as a treatment biomarker for this disease, and consider the DMN effects of individualized therapies for schizophrenia.
基金Supported by the National Natural Science Foundation of China(No.81870685)Beijing Natural Science Foundation(No.7172173)Key Laboratory of Myopia,Ministry of Health(Fudan University)(No.EENTM-15-01)。
文摘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.
基金Project supported by the National Natural Science Foundation of China(No.81771158)the Science Foundation of the Health Commission of Zhejiang Province(Nos.2016147373 and 2019321345),China
文摘The purpose of this study was to explore the differences in interhemispheric functional connectivity in patients with Alzheimer’s disease(AD) and amnestic mild cognitive impairment(aMCI) based on a triple network model consisting of the default mode network(DMN), salience network(SN), and executive control network(ECN). The technique of voxel-mirrored homotopic connectivity(VMHC) analysis was applied to explore the aberrant connectivity of all patients. The results showed that:(1) the statistically significant connections of interhemispheric brain regions included DMN-related brain regions(i.e. precuneus, calcarine, fusiform, cuneus, lingual gyrus, temporal inferior gyrus, and hippocampus), SN-related brain regions(i.e. frontoinsular cortex), and ECN-related brain regions(i.e. frontal middle gyrus and frontal inferior);(2) the precuneus and frontal middle gyrus in the AD group exhibited lower VMHC values than those in the aMCI and healthy control(HC) groups, but no significant difference was observed between the a MCI and HC groups; and(3) significant correlations were found between peak VMHC results from the precuneus and Mini Mental State Examination(MMSE) and Montreal Cognitive Scale(MOCA) scores and their factor scores in the AD, a MCI, and AD plus aMCI groups, and between the results from the frontal middle gyrus and MOCA factor scores in the a MCI group. These findings indicated that impaired interhemispheric functional connectivity was observed in AD and could be a sensitive neuroimaging biomarker for AD. More specifically, the DMN was inhibited, while the SN and ECN were excited. VMHC results were correlated with MMSE and MOCA scores, highlighting that VMHC could be a sensitive neuroimaging biomarker for AD and the progression from aMCI to AD.
基金supported by the Science and Technology Foundation of Guangdong Province of China,No.2012B031800305
文摘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.
基金sponsored by a grant from the National Natural Science Foundation of China,No.30973084-C160801,C010604the Natural Science Foundation of Anhui Province,No.11040606M167
文摘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.
基金supported by Chinese Academy of Sciences(No.201491)“Light of West China” Program(201491)
文摘Previous studies revealed that the error of pole coordinate prediction will significantly increase for a prediction period longer than 100 days, and this is mainly caused by short period oscillations. Empirical mode decomposition （EMD）, which is increasingly popular and has advantages over classical wavelet decomposition, can be used to remove short period variations from observed time series of pole co- ordinates. A hybrid model combing EMD and extreme learning machine （ELM）, where high frequency signals are removed and processed time series is then modeled and predicted, is summarized in this paper. The prediction performance of the hybrid model is compared with that of the ELM-only method created from original time series. The results show that the proposed hybrid model outperforms the pure ELM method for both short-term and long-term prediction of pole coordinates. The improvement of prediction accuracy up to 360 days in the future is found to be 24.91% and 26.79% on average in terms of mean absolute error （MAE） for the xp and yp components of pole coordinates, respectively.
基金supported by the National Natural Science Foundation of China,Nos.82271963(to HJL),81771806(to HJL),61936013(to HJL),82001914(to ZCT),81871511(to HZ)National Key R&D Program of China,No.2021YFA1301603(to ZCT)the Natural Science Foundation of Beijing,No.7212051(to HJL).
文摘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.
文摘The provision mode of the telecommunication service has experienced an evolving process, and showing the developing trend from distributed to centralized, from integrated to separated, and from closed to open. To suit this trend, there will be three provision modes as Session Initiation Protocol (SIP) server, Open Service Access (OSA) application server and intelligent network(IN) in Next Generation Network (NGN), provides all kinds of services and applications to the subscribers. With the popularity of broadband access and Internet, the NGN will provide single telecommunication service and act as the important national infrastructure to offer various information services to the subscribers. The service provision mode will be more open, diversified, and individualized.
文摘Localizing network legal supervision based on national conditions, legal traditions and the needs of economic and political development is the basis to manage and administrate the network by law. Adjusted to media convergence and the needs of network cultural industry development, China has made the lawmaking of media transform from practical service oriented management to functional oriented management of media. This strategy aims to prevent network medium risk effectively according to network communication regularity.
文摘In this paper, an extended Kendall model for the priority scheduling input-line group output with multi-channel in Asynchronous Transfer Mode （ATM） exchange system is proposed and then the mean method is used to model mathematically the non-typical non-anticipative PRiority service （PR） model. Compared with the typical and non-anticipative PR model, it expresses the characteristics of the priority scheduling input-line group output with multi-channel in ATM exchange system. The simulation experiment shows that this model can improve the HOL block and the performance of input-queued ATM switch network dramatically. This model has a better developing prospect in ATM exchange system.
文摘Objective： To investigate functional connectivity within default mode network （DMN） and ex-ecutive control network （ECN） in vascular cognitive im-pairment, no dementia （VCIND）. Methods： Twenty-eight VCIND patients and sixteen healthy controls were recruit-ed. A seed-based connectivity analysis was performed us-ing data from resting-state functional magnetic resonance imaging （fMRI）. Based on previous fndings, posteriorcingulate cortex （PCC） and dorsolateral prefrontal cortex （DLPFC） were chosen as regions of interest to study these networks.One-sample t-test and two-sample t-test were used for statistical analysis. Results： Compared with thecontrols, the VCIND group exhibited increased functional activity in such DMN regions as the left inferior temporal gyrus, parahippocampal gyrus, and medial frontal gyrus. The VCIND group had decreased functional connectivity of DMN at right superior frontal gyrus, left mid-cingu-late area, the medial part of left superior frontal gyrus, and bilateral medial frontal gyrus. The VCIND group also showed decreased functional connectivity of ECN pri-marilyat left inferior parietal gyrus, right angular gyrus, right middle occipital gyrus, and right middle frontal cor-tex. Conclusions： Increased functional connectivity with-in DMN and decreased functional connectivity within ECN suggested dysfunction of these two networks, which mightbe associated with the cognitive defcitsin patients with VCIND. These fndingsmay help usunderstandthe pathogenesis and clinical characteristics of VCIND.
基金supported by grants from the National High Technology Research Development Project (863 Project) of China (2015AA020504)the National Natural Science Foundation of China (31571111 and 31200857)the Fundamental Research Funds for the Central Universities of China (SW1509113)
文摘Neuroimaging techniques such as functional magnetic resonance imaging and positron emission tomography have provided an unprecedented neurobiological perspective for research on personality traits. Evidence from task-related neuroimaging has shown that extraversion is associated with activations in regions of the anterior cingulate cortex, dorsolateral prefrontal cortex, middle temporal gyrus and the amygdala. Currently, resting-state neuroimaging is being widely used in cognitive neuroscience. Initial exploration of extraversion has revealed correlations with the medial prefrontal cortex, anterior cingulate cortex, insular cortex, and the precuneus. Recent research work has indicated that the long-range temporal dependence of the resting-state spontaneous oscillation has high test-retest reliability. Moreover, the long-range temporal dependence of the resting-state networks is highly correlated with personality traits, and this can be used for the prediction of extraversion. As the long-range temporal dependence reflects real-time information updating in individuals, this method may provide a new approach to research on personality traits.
基金supported by the National Natural Science Foundation of China,No.81471120Fund Projects in Technology of the Foundation Strengthening Program of China,No.2019-JCJQ-JJ-151(both to XZ).
文摘Numerous studies have shown abnormal brain functional connectivity in individuals with Alzheimer’s disease(AD)or amnestic mild cognitive impairment(aMCI).However,most studies examined traditional resting state functional connections,ignoring the instantaneous connection mode of the whole brain.In this case-control study,we used a new method called dynamic functional connectivity(DFC)to look for abnormalities in patients with AD and aMCI.We calculated dynamic functional connectivity strength from functional magnetic resonance imaging data for each participant,and then used a support vector machine to classify AD patients and normal controls.Finally,we highlighted brain regions and brain networks that made the largest contributions to the classification.We found differences in dynamic function connectivity strength in the left precuneus,default mode network,and dorsal attention network among normal controls,aMCI patients,and AD patients.These abnormalities are potential imaging markers for the early diagnosis of AD.
基金supported by a grant from the Medical Scientific Research Programs of Nanjing Military Command,No.14MS122
文摘Traumatic brain injury survivors often experience cognitive deficits and neuropsychiatric symptoms.However,the neurobiological mechanisms underlying specific impairments are not fully understood.Advances in neuroimaging techniques（such as diffusion tensor imaging and functional MRI）have given us new insights on structural and functional connectivity patterns of the human brain in both health and disease.The connectome derived from connectivity maps reflects the entire constellation of distributed brain networks.Using these powerful neuroimaging approaches,changes at the microstructural level can be detected through regional and global properties of neuronal networks.Here we will review recent developments in the study of brain network abnormalities in traumatic brain injury,mainly focusing on structural and functional connectivity.Some connectomic studies have provided interesting insights into the neurological dysfunction that occurs following traumatic brain injury.These techniques could eventually be helpful in developing imaging biomarkers of cognitive and neurobehavioral sequelae,as well as predicting outcome and prognosis.
