Changes in brain functional network connectivity after stroke简

Studies have shown that functional network connection models can be used to study brain net- work changes in patients with schizophrenia. In this study, we inferred that these models could also be used to explore functional network connectivity changes in stroke patients. We used independent component analysis to find the motor areas of stroke patients, which is a novel way to determine these areas. In this study, we collected functional magnetic resonance imaging datasets from healthy controls and right-handed stroke patients following their first ever stroke. Using independent component analysis, six spatially independent components highly correlat- ed to the experimental paradigm were extracted. Then, the functional network connectivity of both patients and controls was established to observe the differences between them. The results showed that there were 11 connections in the model in the stroke patients, while there were only four connections in the healthy controls. Further analysis found that some damaged connections may be compensated for by new indirect connections or circuits produced after stroke. These connections may have a direct correlation with the degree of stroke rehabilitation. Our findings suggest that functional network connectivity in stroke patients is more complex than that in hea- lthy controls, and that there is a compensation loop in the functional network following stroke. This implies that functional network reorganization plays a very important role in the process of rehabilitation after stroke.     

Aberrant functional brain network dynamics in patients with functional constipation

The aberrant static functional connectivity of brain network has been widely investigated in patients with functional constipation (FCon). However, the dynamics of brain functional connectivity in FCon patients remained unknown. This study aimed to detect the brain dynamics of functional connectivity states and network topological organizations of FCon patients and investigate the correlations of the aberrant brain dynamics with symptom severity. Eighty‐three FCon patients and 80 healthy subjects (HS) were included in data analysis. The spatial group independent component analysis, sliding‐window approach, k‐means clustering, and graph‐theoretic analysis were applied to investigate the dynamic temporal properties and coupling patterns of functional connectivity states, as well as the time‐variation of network topological organizations in FCon patients. Four reoccurring functional connectivity states were identified in k‐means clustering analysis. Compared to HS, FCon patients manifested the lower occurrence rate and mean dwell time in the state with a complex connection between default mode network and cognitive control network, as well as the aberrant anterior insula–cortical coupling patterns in this state, which were significantly correlated with the symptom severity. The graph‐theoretic analysis demonstrated that FCon patients had higher sample entropy at the nodal efficiency of anterior insula than HS. The current findings provided dynamic perspectives for understanding the brain connectome of FCon and laid the foundation for the potential treatment of FCon based on brain connectomics.     

Exploration and modulation of brain network interactions with noninvasive brain stimulation in combination with neuroimaging

Much recent work in systems neuroscience has focused on how dynamic interactions between different cortical regions underlie complex brain functions such as motor coordination, language and emotional regulation. Various studies using neuroimaging and neurophysiologic techniques have suggested that in many neuropsychiatric disorders, these dynamic brain networks are dysregulated. Here we review the utility of combined noninvasive brain stimulation and neuroimaging approaches towards greater understanding of dynamic brain networks in health and disease. Brain stimulation techniques, such as transcranial magnetic stimulation and transcranial direct current stimulation, use electromagnetic principles to alter brain activity noninvasively, and induce focal but also network effects beyond the stimulation site. When combined with brain imaging techniques such as functional magnetic resonance imaging, positron emission tomography and electroencephalography, these brain stimulation techniques enable a causal assessment of the interaction between different network components, and their respective functional roles. The same techniques can also be applied to explore hypotheses regarding the changes in functional connectivity that occur during task performance and in various disease states such as stroke, depression and schizophrenia. Finally, in diseases characterized by pathologic alterations in either the excitability within a single region or in the activity of distributed networks, such techniques provide a potential mechanism to alter cortical network function and architectures in a beneficial manner.     

Abnormal brain functional network dynamics in sleep-related hypermotor epilepsy

Aims

This study aimed to use resting-state functional magnetic resonance imaging (rs-fMRI) to determine the temporal features of functional connectivity states and changes in connectivity strength in sleep-related hypermotor epilepsy (SHE).

Methods

High-resolution T1 and rs-fMRI scanning were performed on all the subjects. We used a sliding-window approach to construct a dynamic functional connectivity (dFC) network. The k-means clustering method was performed to analyze specific FC states and related temporal properties. Finally, the connectivity strength between the components was analyzed using network-based statistics (NBS) analysis. The correlations between the abovementioned measures and disease duration were analyzed.

Results

After k-means clustering, the SHE patients mainly exhibited two dFC states. The frequency of state 1 was higher, which was characterized by stronger connections within the networks; state 2 occurred at a relatively low frequency, characterized by stronger connections between networks. SHE patients had greater fractional time and a mean dwell time in state 2 and had a larger number of state transitions. The NBS results showed that SHE patients had increased connectivity strength between networks. None of the properties was correlated with illness duration among patients with SHE.

Conclusion

The patterns of dFC patterns may represent an adaptive and protective mode of the brain to deal with epileptic seizures.     

难治性癫痫患者脑网络介数及其异常脑区间功能连接变化研究

目的基于图论的分析方法了解难治性癫痫患者脑功能网络介数属性变化,探讨介数异常脑区间功能连接改变的意义。方法采集难治性癫痫患者及健康被试RS-f MRI数据后,通过Gretna中Network Analysis模块预处理并计算出各脑区的介数值,经统计检验找出介数值有差异脑区;运用REST软件将上述脑区作为ROI两两之间做功能连接,经统计检验后找出脑区间差异的连接。结果与对照组相比,癫痫组介数值升高的脑区有右侧额下回三角部、右侧嗅皮质;介数值下降的脑区有右侧额上回背外侧、左侧额上回眶部、左侧前扣带回、右侧颞上回、右侧颞下回;与健康被试相比,额下回三角部与颞上回之间的连接降低。结论难治性癫痫患者脑功能网络介数属性及异常脑区间的功能连接改变,引起脑区间信息交流的障碍,可能导致癫痫患者认知功能的损伤。     

立体定向放射外科治疗脑转移瘤患者颅内出血相关风险因素分析

目的 分析接受立体定向放射外科（SRS）治疗的脑转移瘤（BM）患者颅内出血（ICH）发生和致死的风险因素。方法 筛选符合纳排标准的BM患者392例,分析其临床资料,包括患者项目、SRS项目、血液学项目和影像学项目。首先,根据患者接受SRS后是否出血分为ICH组（n=134）和非ICH组（n=258）。对两组行Logistic回归分析ICH发生的风险因素。之后,再分析ICH组致死的风险因素。结果 有ICH史、原发灶为恶性黑色素瘤是接受SRS后BM患者ICH发生的风险因素,有ICH史和原发灶为恶性黑色素瘤的患者ICH发生风险分别提高了7.433和1.430倍（均P＜0.05）。ICH组7 d内和30 d内死亡率分别为11.19%和25.37%。高血压、血小板计数、脑疝和脑积水是7 d内死亡的危险因素（均P＜0.05）。脑疝和脑积水是30 d内死亡的危险因素（均P＜0.05）。结论 对于具备相应风险因素的患者,需提前做好预防和治疗准备,从而降低ICH发生和致死率。 [国际神经病学神经外科学杂志, 2023, 50(6): 34-39]     

Pathological uncoupling between amplitude and connectivity of brain fluctuations in epilepsy

Amplitude and functional connectivity are two fundamental parameters for describing the spontaneous brain fluctuations. These two parameters present close coupling in physiological state, and present different alteration patterns in epilepsy revealed by functional MRI (fMRI). We hypothesized that the alteration of coupling between these two imaging parameters may be underpinned by specific pathological factors of epilepsy, and can be employed to improve the capability for epileptic focus detection. Forty‐seven patients (26 left‐ and 21 right‐sided) with mesial temporal lobe epilepsy (mTLE) and 32 healthy controls underwent resting‐state fMRI scans. All patients were detected to have interictal epileptic discharges on simultaneous electroencephalograph (EEG) recordings. Amplitude‐connectivity coupling was calculated by correlating amplitude and functional connectivity density of low‐frequency brain fluctuations. We observed reduced amplitude‐connectivity coupling associated with epileptic discharges in the mesial temporal regions in both groups of patients, and increased coupling associated with epilepsy durations in the posterior regions of the default‐mode network in the right‐sided patients. Moreover, we proposed a new index of amplitude subtracting connectivity, which elevated imaging contrast for differentiating the patients from the controls. The findings indicated that epileptic discharges and chronic damaging effect of epilepsy might both contribute to alterations of amplitude‐connectivity coupling in different pivotal regions in mTLE. Investigation on imaging coupling provides synergistic approach for describing brain functional changing features in epilepsy. Hum Brain Mapp 36:2756–2766, 2015. © 2015 Wiley Periodicals, Inc.     

Deep brain stimulation in patients with refractory temporal lobe epilepsy

PURPOSE: This pilot study prospectively evaluated the efficacy of long-term deep brain stimulation (DBS) in medial temporal lobe (MTL) structures in patients with MTL epilepsy. METHODS: Twelve consecutive patients with refractory MTL epilepsy were included in this study. The protocol included invasive video-EEG monitoring for ictal-onset localization and evaluation for subsequent stimulation of the ictal-onset zone. Side effects and changes in seizure frequency were carefully monitored. RESULTS: Ten of 12 patients underwent long-term MTL DBS. Two of 12 patients underwent selective amygdalohippocampectomy. After mean follow-up of 31 months (range, 12-52 months), one of 10 stimulated patients are seizure free (>1 year), one of 10 patients had a >90% reduction in seizure frequency; five of 10 patients had a seizure-frequency reduction of > or =50%; two of 10 patients had a seizure-frequency reduction of 30-49%; and one of 10 patients was a nonresponder. None of the patients reported side effects. In one patient, MRI showed asymptomatic intracranial hemorrhages along the trajectory of the DBS electrodes. None of the patients showed changes in clinical neurological testing. Patients who underwent selective amygdalohippocampectomy are seizure-free (>1 year), AEDs are unchanged, and no side effects have occurred. CONCLUSIONS: This open pilot study demonstrates the potential efficacy of long-term DBS in MTL structures that should now be further confirmed by multicenter randomized controlled trials.     

Functional network estimation using multigraph learning with application to brain maturation study

Although most dramatic structural changes occur in the perinatal period, a growing body of evidences demonstrates that adolescence and early adulthood are also important for substantial neurodevelopment. We were thus motivated to explore brain development during puberty by evaluating functional connectivity network (FCN) differences between childhood and young adulthood using multi‐paradigm task‐based functional magnetic resonance imaging (fMRI) measurements. Different from conventional multigraph based FCN construction methods where the graph network was built independently for each modality/paradigm, we proposed a multigraph learning model in this work. It promises a better fitting to FCN construction by jointly estimating brain network from multi‐paradigm fMRI time series, which may share common graph structures. To investigate the hub regions of the brain, we further conducted graph Fourier transform (GFT) to divide the fMRI BOLD time series of a node within the brain network into a range of frequencies. Then we identified the hub regions characterizing brain maturity through eigen‐analysis of the low frequency components, which were believed to represent the organized structures shared by a large population. The proposed method was evaluated using both synthetic and real data, which demonstrated its effectiveness in extracting informative brain connectivity patterns. We detected 14 hub regions from the child group and 12 hub regions from the young adult group. We show the significance of these findings with a discussion of their functions and activation patterns as a function of age. In summary, our proposed method can extract brain connectivity network more accurately by considering the latent common structures between different fMRI paradigms, which are significant for both understanding brain development and recognizing population groups of different ages.     

Seizure outcome after hippocampal deep brain stimulation in a prospective cohort of patients with refractory temporal lobe epilepsy

PurposeIn this study, we present the results obtained from a series of patients with refractory temporal lobe epilepsy (r-TLE) who underwent hippocampal deep brain stimulation (Hip-DBS).MethodsNine consecutive adult patients were studied. Low-frequency and high-frequency stimulation was carried out immediately after the insertion of each electrode. Chronic continuous high-frequency stimulation was used during treatment. The mean follow-up time was 30.1 months. The mean age of the patients was 37.2 years. The MRI scan was normal in three patients; four patients had bilateral mesial temporal sclerosis (MTS), and two had unilateral MTS.ResultsThe patients with unilateral MTS received unilateral implantation and experienced a 76% and an 80% reduction in seizure frequency after Hip-DBS. All patients with normal MRI scans were implanted bilaterally. Two of these patients received unilateral activation of the electrodes and experienced a 97% and an 80% reduction in seizure frequency; the third patient had bilateral activation of the device and was a non-responder. All patients with bilateral MTS were implanted bilaterally. Three of these patients received unilateral activation of the device and experienced a 66%, a 66% and a 100% reduction in seizure frequency after Hip-DBS; one patient had bilateral electrode activation, and was a non-responder. Whenever present, generalised tonic–clonic seizures disappeared completely after Hip-DBS.ConclusionsAlthough performed on a relatively small number of patients, Hip-DBS was safe and effective in our patients with r-TLE. Seven of the nine patients were considered responders. Hip-DBS might represent a useful therapeutic option in patients with refractory temporal lobe epilepsy who were not candidates for resective surgery or have had previous failed procedures.     

难治性癫痫患者脑网络效率的变化研究

目的 运用图论分析法探讨难治性癫痫患者脑网络效率的改变.方法 回顾性纳入2015年10月至2016年6月安徽医科大学附属省立医院神经外科收治的26例难治性癫痫患者（癫痫组）,另纳入同期招募的26名健康志愿者（健康对照组）.采集两组受试者静息态功能磁共振成像（fMRI）数据,使用GRETNA软件中Network Construction模块进行数据预处理得到脑网络的矩阵,运用Network Analysis模块进行脑网络分析,得到网络效率属性,以连接矩阵稀疏度（Sparsity）为阈值,并在阈值为0.05≤Sparsity≤0.40范围内比较两组的脑网络效率.结果 癫痫组与健康对照组的年龄、性别及受教育程度的差异均无统计学意义（均P ＞0.05）,而癫痫组患者的蒙特利尔认知评估量表（MoCA）评分较健康对照组显著偏低[分别为（19.6±2.7）分、（26.8±3.6）分,P=0.026].癫痫组患者全局网络效率在阈值为0.11≤Sparsity≤0.18范围下明显低于健康对照组（P＜0.05）,且在0.05≤Sparsity≤0.40范围内比较两组的局部网络效率均值发现,癫痫组患者除右侧海马较健康对照组局部效率降低外（P＜0.05）,右侧岛叶、左侧岛盖部额下回、左侧颞下回、左侧枕上回、右侧苍白球等脑区局部效率增高（均P＜0.05）.结论 难治性癫痫患者全局网络效率在一定阈值范围内明显低于健康受试者,并且局部脑区的局部效率出现异常,可能是难治性癫痫患者相关临床症状的神经网络基础.     

A toolbox for brain network construction and classification (BrainNetClass)

Brain functional network has been increasingly used in understanding brain functions and diseases. While many network construction methods have been proposed, the progress in the field still largely relies on static pairwise Pearson's correlation‐based functional network and group‐level comparisons. We introduce a “Brain Network Construction and Classification (BrainNetClass)” toolbox to promote more advanced brain network construction methods to the filed, including some state‐of‐the‐art methods that were recently developed to capture complex and high‐order interactions among brain regions. The toolbox also integrates a well‐accepted and rigorous classification framework based on brain connectome features toward individualized disease diagnosis in a hope that the advanced network modeling could boost the subsequent classification. BrainNetClass is a MATLAB‐based, open‐source, cross‐platform toolbox with both graphical user‐friendly interfaces and a command line mode targeting cognitive neuroscientists and clinicians for promoting reliability, reproducibility, and interpretability of connectome‐based, computer‐aided diagnosis. It generates abundant classification‐related results from network presentations to contributing features that have been largely ignored by most studies to grant users the ability of evaluating the disease diagnostic model and its robustness and generalizability. We demonstrate the effectiveness of the toolbox on real resting‐state functional MRI datasets. BrainNetClass (v1.0) is available at https://github.com/zzstefan/BrainNetClass .     

Distinct brain structural‐functional network topological coupling explains different outcomes in tinnitus patients treated with sound therapy

Topological properties, which serve as the core of the neural network, and their couplings can reflect different therapeutic effects in tinnitus patients. We hypothesized that tinnitus patients with different outcomes after sound therapy (narrowband noise) would have distinct brain network topological alterations. Diffusion tensor imaging and resting‐state functional magnetic resonance imaging (fMRI) were prospectively performed in 60 patients with idiopathic tinnitus and 57 healthy controls (HCs). Graph‐theoretical network analyses of structural connectivity (SC), functional connectivity (FC), and SC and FC coupling were performed. Associations between clinical performance and graph‐theoretical features were also analyzed. Treatment was effective (effective group; EG) in 28 patients and ineffective (ineffective group; IG) in 32 patients. For FC, the patients in the EG showed higher local efficiency than patients in the IG. For SC, patients in both the EG and IG displayed lower normalized characteristic path length, characteristic path length, and global efficiency than the HCs. More importantly, patients in the IG had higher coupling than the HCs, whereas there was no difference in coupling between patients in the EG and HCs. Additionally, there were significant associations between the SC features and clinical performance in patients in the EG. Our findings demonstrate that tinnitus patients exhibited significant brain network topological alterations, especially in the structural brain network. More importantly, patients who demonstrated different curative effects showed distinct SC‐FC topological coupling properties. SC‐FC coupling could be an indicator that could be used to predict prognoses in patients with idiopathic tinnitus before sound therapy.     

额叶癫痫脑电模式分析

目的 探讨额叶癫痫的脑电模式特点.方法 回顾性分析2016年1月至2018年4月手术治疗的额叶有确切结构病灶或立体定向脑电图(SEEG)证实额叶起源的51例癫痫的临床资料,51例均行头皮视频脑电图(VEEG)监测,21例行SEEG监测.结果 ①VEEG表现:背景正常29例(56.86％),异常22例(43.14％);间...     

微电极引导立体定向核团毁损和脑深部电刺激治疗帕金森病

目的研究微电极引导立体定向颅内核团毁损和脑深部电刺激手术(deep brain stimulation,DBS)治疗帕金森病的临床疗效。方法分析我院116例应用微电极引导立体定向核团毁损术和85例应用脑深部电刺激术治疗的帕金森病患者的临床资料,获得术前、术后和DBS开启后6个月、1年、3年及5年的不同服药状态下帕金森病联合评分量表(UPDRS)的评分,比较手术前后UPDRS运动评分的差异。结果核团毁损术和DBS在术后6个月、1年和3年的随访中均能显著改善患者术前UPDRS运动评分,在第5年仅DBS组UPDRS运动评分较术前有改善,同时DBS组患者术后抗帕金森病药物用量较术前减少。结论核团毁损和脑深部电刺激手术均能显著改善帕金森病患者的UPDRS运动评分,DBS疗效更为长久。     

Middle short gyrus of the insula implicated in speech production: Intracerebral electric stimulation of patients with epilepsy

Purpose: Different lines of evidence have suggested an involvement of the insular cortex in speech production. These have included results from lesion studies, functional imaging techniques, and electrical stimulation of the human insular cortex during invasive evaluation of epileptic patients. Methods: We evaluated 25 patients who had drug refractory focal epilepsy with at least one electrode stereotactically implanted in the insular cortex. Results: Eight responses to insular cortex electrical stimulation were reported by five patients as speech arrest (five responses) and a lowering of voice intensity (three responses). Conclusions: Data from this study implicate the middle short gyrus of the insula in the production of speech and show the importance of intrainsular electrode implantation during invasive pre‐resection evaluation by stereo‐electroencephalography (SEEG) when speech arrest occurs early in seizure semiology.