Disrupted brain functional networks in patients with end-stage renal disease undergoing hemodialysis

Patterns of change in whole-brain functional networks remain poorly understood in patients with end-stage renal disease (ESRD) undergoing hemodialysis (HD). We conducted a prospective research to investigate the topological properties of whole-brain functional networks in those patients using a graph-based network analysis. Resting-state functional magnetic resonance imaging was performed on 51 ESRD patients (25 HD and 26 nondialysis patients) and 36 healthy controls (HCs). We compared the topological properties of brain functional networks among the three groups, and analyzed the relationships between those significant parameters and clinical variables in ESRD patients. Progressively disrupted global topological organizations were observed from nondialysis patients to HD patients compared with HCs (all p < 0.05 after Bonferroni correction). HD patients, relative to HCs, showed significantly decreased nodal centralities in the left temporal pole: superior temporal gyrus, bilateral median cingulate and paracingulate gyri, bilateral hippocampus, bilateral parahippocampal gyrus, and bilateral amygdala, and showed increased nodal centralities in the orbital part of the bilateral middle frontal gyrus, left cuneus, and left superior occipital gyrus (all p < 0.05 after Bonferroni correction). Furthermore, nodal centralities in the bilateral hippocampus were significantly decreased in HD patients compared with nondialysis patients (p < 0.05 after Bonferroni correction). Dialysis duration negatively correlated with global efficiency in ESRD patients undergoing HD (r = −0.676, FDR q = 0.004). This study indicates that ESRD patients exhibit disruptions in brain functional networks, which are more severe in HD patients, and these alterations are correlated with cognitive performance and clinical markers.     

Disrupted topological organization of resting‐state functional brain networks in cerebral small vessel disease

We aimed to investigate alterations in functional brain networks and assess the relationship between functional impairment and topological network changes in cerebral small vessel disease (CSVD) patients with and without cerebral microbleeds (CMBs). We constructed individual whole‐brain, region of interest (ROI) level functional connectivity (FC) networks for 24 CSVD patients with CMBs (CSVD‐c), 42 CSVD patients without CMBs (CSVD‐n), and 36 healthy controls (HCs). Then, we used graph theory analysis to investigate the global and nodal topological disruptions between groups and relate network topological alterations to clinical parameters. We found that both the CSVD and control groups showed efficient small‐world organization in FC networks. However, compared to CSVD‐n patients and controls, CSVD‐c patients exhibited a significantly decreased clustering coefficient, global efficiency, and local efficiency and an increased shortest path length, indicating a disrupted balance between local specialization and global integration in FC networks. Although both the CSVD and control groups showed highly similar hub distributions, the CSVD‐c group exhibited significantly altered nodal betweenness centrality (BC), mainly distributed in the default mode network (DMN), attention, and visual functional areas. There were almost no global or regional alterations between CSVD‐n patients and controls. Furthermore, the altered nodal BC of the right anterior/posterior cingulate gyrus and left cuneus were significantly correlated with cognitive parameters in CSVD patients. These results suggest that CSVD patients with and without CMBs had segregated disruptions in the topological organization of the intrinsic functional brain network. This study advances our current understanding of the pathophysiological mechanisms underlying CSVD.     

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.     

Disruptions of brain structural network in end-stage renal disease patients with long-term hemodialysis and normal-appearing brain tissues

ObjectiveEnd-stage renal disease (ESRD) patients on hemodialysis were demonstrated to exhibit silent and invisible white-matter alterations which would likely lead to disruptions of brain structural networks. Therefore, the purpose of this study was to investigate the disruptions of brain structural network in ESRD patients.Materials and methodsThiry-three ESRD patients with normal-appearing brain tissues and 29 age- and gender-matched healthy controls were enrolled in this study and underwent both cognitive ability screening instrument (CASI) assessment and diffusion tensor imaging (DTI) acquisition. Brain structural connectivity network was constructed using probabilistic tractography with automatic anatomical labeling template. Graph-theory analysis was performed to detect the alterations of node-strength, node-degree, node-local efficiency, and node-clustering coefficient in ESRD patients. Correlational analysis was performed to understand the relationship between network measures, CASI score, and dialysis duration.ResultsStructural connectivity, node-strength, node-degree, and node-local efficiency were significantly decreased, whereas node-clustering coefficient was significantly increased in ESRD patients as compared with healthy controls. The disrupted local structural networks were generally associated with common neurological complications of ESRD patients, but the correlational analysis did not reveal significant correlation between network measures, CASI score, and dialysis duration.ConclusionGraph-theory analysis was helpful to investigate disruptions of brain structural network in ESRD patients with normal-appearing brain tissues.     

Altered single‐subject gray matter structural networks in drug‐naïve attention deficit hyperactivity disorder children

Altered topological organization of brain structural covariance networks has been observed in attention deficit hyperactivity disorder (ADHD). However, results have been inconsistent, potentially related to confounding medication effects. In addition, since structural networks are traditionally constructed at the group level, variabilities in individual structural features remain to be well characterized. Structural brain imaging with MRI was performed on 84 drug‐naïve children with ADHD and 83 age‐matched healthy controls. Single‐subject gray matter (GM) networks were obtained based on areal similarities of GM, and network topological properties were analyzed using graph theory. Group differences in each topological metric were compared using nonparametric permutation testing. Compared with healthy subjects, GM networks in ADHD patients demonstrated significantly altered topological characteristics, including higher global and local efficiency and clustering coefficient, and shorter path length. In addition, ADHD patients exhibited abnormal centrality in corticostriatal circuitry including the superior frontal gyrus, orbitofrontal gyrus, medial superior frontal gyrus, precentral gyrus, middle temporal gyrus, and pallidum (all p < .05, false discovery rate [FDR] corrected). Altered global and nodal topological efficiencies were associated with the severity of hyperactivity symptoms and the performance on the Stroop and Wisconsin Card Sorting Test tests (all p < .05, FDR corrected). ADHD combined and inattention subtypes were differentiated by nodal attributes of amygdala (p < .05, FDR corrected). Alterations in GM network topologies were observed in drug‐naïve ADHD patients, in particular in frontostriatal loops and amygdala. These alterations may contribute to impaired cognitive functioning and impulsive behavior in ADHD.     

Disrupted brain connectivity networks in acute ischemic stroke patients

Neuroimaging studies have shown that local brain lesions could result in abnormal information transfer far from the lesion site in acute ischemic stroke (AIS) patients; yet, little is known about alternations of the topological organization of whole-brain networks in AIS. By using resting state functional magnetic resonance imaging (MRI) and graph theory analysis, we systematically investigated the topological properties of the functional brain networks of 28 healthy controls (HC, age: 56.9?±?0.45 years) and 29 AIS (age: 57.6?±?0.21 years) with proximal anterior circulation occlusion within 12 h of symptom onset. In our results, both the AIS and HC groups exhibited small-world network organization, suggesting a functional balance between local specialization and global integration. However, compared with the HC, the AIS patients had a lower shortest path length and higher global efficiency, indicating a tendency of randomization in patients’ functional brain networks. The AIS patients had an increased nodal degree in the precuneus (PCUN), middle frontal gyrus (MFG), medial part of the superior frontal gyrus (SFGmed), orbital part of the middle frontal gyrus, and the opercular part of the inferior frontal gyrus, and increased nodal efficiency in the PUCN, MFG, SFGmed, and the angular gyrus. The decreased nodal degree in AIS was found in the heschl gyrus (HES), and no significant decreased nodal efficiency was observed. The dysfunctional connections were mainly concentrated in the HES and prefrontal cortex. Furthermore, the altered nodal centrality of the MFG and abnormal functional connectivity in AIS were associated with patients’ Mini-Mental State Examination scores. These results suggested that interrupted functional connectivity in language system organization after focal brain lesions could also result in disruptions in the topological organization of other brain circuits, and this may contribute to disturbances in cognition in AIS patients.     

Aberrant white matter networks mediate cognitive impairment in patients with silent lacunar infarcts in basal ganglia territory

Silent lacunar infarcts, which are present in over 20% of healthy elderly individuals, are associated with subtle deficits in cognitive functions. However, it remains largely unclear how these silent brain infarcts lead to cognitive deficits and even dementia. Here, we used diffusion tensor imaging tractography and graph theory to examine the topological organization of white matter networks in 27 patients with silent lacunar infarcts in the basal ganglia territory and 30 healthy controls. A whole-brain white matter network was constructed for each subject, where the graph nodes represented brain regions and the edges represented interregional white matter tracts. Compared with the controls, the patients exhibited a significant reduction in local efficiency and global efficiency. In addition, a total of eighteen brain regions showed significantly reduced nodal efficiency in patients. Intriguingly, nodal efficiency–behavior associations were significantly different between the two groups. The present findings provide new aspects into our understanding of silent infarcts that even small lesions in subcortical brain regions may affect large-scale cortical white matter network, as such may be the link between subcortical silent infarcts and the associated cognitive impairments. Our findings highlight the need for network-level neuroimaging assessment and more medical care for individuals with silent subcortical infarcts.     

Breakdown of the affective‐cognitive network in functional dystonia

Previous studies suggested that brain regions subtending affective‐cognitive processes can be implicated in the pathophysiology of functional dystonia (FD). In this study, the role of the affective‐cognitive network was explored in two phenotypes of FD: fixed (FixFD) and mobile dystonia (MobFD). We hypothesized that each of these phenotypes would show peculiar functional connectivity (FC) alterations in line with their divergent disease clinical expressions. Resting state fMRI (RS‐fMRI) was obtained in 40 FD patients (12 FixFD; 28 MobFD) and 43 controls (14 young FixFD‐age‐matched [yHC]; 29 old MobFD‐age‐matched [oHC]). FC of brain regions of interest, known to be involved in affective‐cognitive processes, and independent component analysis of RS‐fMRI data to explore brain networks were employed. Compared to HC, all FD patients showed reduced FC between the majority of affective‐cognitive seeds of interest and the fronto‐subcortical and limbic circuits; enhanced FC between the right affective‐cognitive part of the cerebellum and the bilateral associative parietal cortex; enhanced FC of the bilateral amygdala with the subcortical and posterior cortical brain regions; and altered FC between the left medial dorsal nucleus and the sensorimotor and associative brain regions (enhanced in MobFD and reduced in FixFD). Compared with yHC and MobFD patients, FixFD patients had an extensive pattern of reduced FC within the cerebellar network, and between the majority of affective‐cognitive seeds of interest and the sensorimotor and high‐order function (“cognitive”) areas with a unique involvement of dorsal anterior cingulate cortex connectivity. Brain FC within the affective‐cognitive network is altered in FD and presented specific features associated with each FD phenotype, suggesting an interaction between brain connectivity and clinical expression of the disease.     

Altered resting state functional brain network topology in chemotherapy-treated breast cancer survivors

Many women with breast cancer, especially those treated with chemotherapy, experience cognitive decline due in part to neurotoxic brain injury. Recent neuroimaging studies suggest widespread brain structural abnormalities pointing to disruption of large-scale brain networks. We applied resting state functional magnetic resonance imaging and graph theoretical analysis to examine the connectome in breast cancer survivors treated with chemotherapy relative to healthy comparison women. Compared to healthy females, the breast cancer group displayed altered global brain network organization characterized by significantly decreased global clustering as well as disrupted regional network characteristics in frontal, striatal and temporal areas. Breast cancer survivors also showed significantly increased self-report of executive function and memory difficulties compared to healthy females. These results suggest that topological organization of both global and regional brain network properties may be disrupted following breast cancer and chemotherapy. This pattern of altered network organization is believed to result in reduced efficiency of parallel information transfer. This is the first report of alterations in large-scale functional brain networks in this population and contributes novel information regarding the neurobiologic mechanisms underlying breast cancer-related cognitive impairment.     

Altered brain functional network dynamics in obsessive–compulsive disorder

Obsessive–compulsive disorder (OCD) is a debilitating and disabling neuropsychiatric disorder, whose neurobiological basis remains unclear. Although traditional static resting‐state magnetic resonance imaging (rfMRI) studies have found aberrant functional connectivity (FC) in OCD, alterations in whole‐brain FC and topological properties in the context of brain dynamics remain relatively unexplored. The rfMRI data of 29 patients with OCD and 40 healthy controls were analyzed using group independent component analysis to obtain independent components (ICs) and a sliding‐window approach to generate dynamic functional connectivity (dFC) matrices. dFC patterns were clustered into three reoccurring states, and state transition metrics were obtained. Then, graph‐theory methods were applied to dFC matrices to calculate the variability of network topological organization. The occurrence of a state (State 1) with the highest modularity index and lowest mean FC between networks was increased significantly in OCD, and the fractional time in brain State 1 was positively correlated with anxiety level in patients. State 1 was characterized by having positive connections within default mode (DMN) and salience networks (SAN), and negative coupling between the two networks. Additionally, ICs belonging to DMN and SAN showed lower temporal variability of nodal degree centrality and efficiency in patients, which was related to longer illness duration and higher current obsession ratings. Our results provide evidence of clinically relevant aberrant dynamic brain activity in OCD. Increased functional segregation among networks and impaired functional flexibility in connections among brain regions in DMN and SAN may play important roles in the neuropathology of OCD.     

Disrupted topological organization of the frontal-mesolimbic network in obese patients

Neuroimaging studies have revealed brain functional abnormalities in frontal-mesolimbic regions in obesity. However, the effects of obesity on brain network topology remains largely unknown. In the current study, we employed resting-state functional magnetic resonance imaging and graph theory methods to investigate obesity-related changes in brain network topology in 26 obese patients and 28 normal weight subjects. Results revealed that the whole-brain networks of the two groups exhibited typical features of small-world topology. Obese patients showed significantly increased shortest path length (Lp) and decreased global efficiency (Eglob). Moreover, decreased nodal-degree/efficiency was found in frontal (medial orbitofrontal cortex-mOFC, rostral anterior cingulate cortex-rACC), striatal (caudate/nucleus accumbens) and limbic regions (insula, amygdala, hippocampus/parahippocampal gyrus) and thalamus in obese patients. Network-based statistics showed that a sub-network, composed of 31 nodes and 30 edges, was significantly disrupted in obese patients; 29 out of 30 connections were associated with the right rACC. In the obese group, Lp and Eglob were negatively correlated with body mass index (BMI, P?<?0.005), and BMI was negatively correlated with nodal-degree/efficiency of the mOFC (P?<?0.001). Findings suggest disruption of the small-world organization and a global reduction of integration of functional brain networks involving the right rACC in obesity and implicating the mOFC in mediating severity.     

Aberrant cerebral network topology and mild cognitive impairment in early Parkinson's disease

The aim of this study was to assess whether mild cognitive impairment (MCI) is associated with disruption in large‐scale structural networks in newly diagnosed, drug‐naïve patients with Parkinson's disease (PD). Graph theoretical analyses were applied to 3T MRI data from 123 PD patients and 56 controls from the Parkinson's progression markers initiative (PPMI). Thirty‐three patients were classified as having Parkinson's disease with mild cognitive impairment (PD‐MCI) using the Movement Disorders Society Task Force criteria, while the remaining 90 PD patients were classified as cognitively normal (PD‐CN). Global measures (clustering coefficient, characteristic path length, global efficiency, small‐worldness) and regional measures (regional clustering coefficient, regional efficiency, hubs) were assessed in the structural networks that were constructed based on cortical thickness and subcortical volume data. PD‐MCI patients showed a marked reduction in the average correlation strength between cortical and subcortical regions compared with controls. These patients had a larger characteristic path length and reduced global efficiency in addition to a lower regional efficiency in frontal and parietal regions compared with PD‐CN patients and controls. A reorganization of the highly connected regions in the network was observed in both groups of patients. This study shows that the earliest stages of cognitive decline in PD are associated with a disruption in the large‐scale coordination of the brain network and with a decrease of the efficiency of parallel information processing. These changes are likely to signal further cognitive decline and provide support to the role of aberrant network topology in cognitive impairment in patients with early PD. Hum Brain Mapp 36:2980–2995, 2015. © 2015 Wiley Periodicals, Inc.     

Large‐scale white matter network reorganization in posttraumatic stress disorder

Recently, graph theoretical approaches applied to neuroimaging data have advanced understanding of the human brain connectome and its abnormalities in psychiatric disorders. However, little is known about the topological organization of brain white matter networks in posttraumatic stress disorder (PTSD). Seventy‐six patients with PTSD and 76 age, gender, and years of education‐matched trauma‐exposed controls were studied after the 2008 Sichuan earthquake using diffusion tensor imaging and graph theoretical approaches. Topological properties of brain networks including global and nodal measurements and modularity were analyzed. At the global level, patients showed lower clustering coefficient (p = .016) and normalized characteristic path length (p = .035) compared with controls. At the nodal level, increased nodal centralities in left middle frontal gyrus, superior and inferior temporal gyrus and right inferior occipital gyrus were observed (p < .05, corrected for false‐discovery rate). Modularity analysis revealed that PTSD patients had significantly increased inter‐modular connections in the fronto‐parietal module, fronto‐striato‐temporal module, and visual and default mode modules. These findings indicate a PTSD‐related shift of white matter network topology toward randomization. This pattern was characterized by an increased global network integration, reflected by increased inter‐modular connections with increased nodal centralities involving fronto‐temporo‐occipital regions. This study suggests that extremely stressful life experiences, when they lead to PTSD, are associated with large‐scale brain white matter network topological reconfiguration at global, nodal, and modular levels.     

Selective Aberrant Functional–Structural Coupling of Multiscale Brain Networks in Subcortical Vascular Mild Cognitive Impairment

Subcortical vascular mild cognitive impairment(svMCI)is a common prodromal stage of vascular dementia.Although mounting evidence has suggested abnormalities in several single brain network metrics,few studies have explored the consistency between functional and structural connectivity networks in svMCI.Here,we constructed such networks using resting-state f MRI for functional connectivity and diffusion tensor imaging for structural connectivity in 30 patients with svMCI and 30 normal controls.The functional networks were then parcellated into topological modules,corresponding to several well-defined functional domains.The coupling between the functional and structural networks was finally estimated and compared at the multiscale network level(whole brain and modular level).We found no significant intergroup differences in the functional–structural coupling within the whole brain;however,there was significantly increased functional–structural coupling within the dorsal attention module and decreased functional–structural coupling within the ventral attention module in the svMCI group.In addition,the svMCI patients demonstrated decreased intramodular connectivity strength in the visual,somatomotor,and dorsal attention modules as well as decreased intermodular connectivity strength between several modules in the functional network,mainly linking the visual,somatomotor,dorsal attention,ventral attention,and frontoparietal control modules.There was no significant correlation between the altered module-level functional–structural coupling and cognitive performance in patients with svMCI.These findings demonstrate for the first time that svMCI is reflected in a selective aberrant topological organization in multiscale brain networks and may improve our understanding of the pathophysiological mechanisms underlying svMCI.     

Network level characteristics in the emotion recognition network after unilateral temporal lobe surgery

The human amygdala is considered a key region for successful emotion recognition. We recently reported that temporal lobe surgery (TLS), including resection of the amygdala, does not affect emotion recognition performance (Journal of Neuroscience, 2018, 38 , 9263). In the present study, we investigate the neural basis of this preserved function at the network level. We use generalized psychophysiological interaction and graph theory indices to investigate network level characteristics of the emotion recognition network in TLS patients and healthy controls. Based on conflicting emotion processing theories, we anticipated two possible outcomes: a substantial increase of the non‐amygdalar connections of the emotion recognition network to compensate functionally for the loss of the amygdala, in line with basic emotion theory versus only minor changes in network level properties as predicted by psychological construction theory. We defined the emotion recognition network in the total sample and investigated group differences on five network level indices (i.e. characteristic path length, global efficiency, clustering coefficient, local efficiency and small‐worldness). The results did not reveal a significant increase in the left or right temporal lobectomy group (compared to the control group) in any of the graph measures, indicating that preserved behavioural emotion recognition in TLS is not associated with a massive connectivity increase between non‐amygdalar nodes at network level. We conclude that the emotion recognition network is robust and functionally able to compensate for structural damage without substantial global reorganization, in line with a psychological construction theory.     

Disrupted brain functional networks in drug‐naïve children with attention deficit hyperactivity disorder assessed using graph theory analysis

Neuroimaging studies have revealed functional brain network abnormalities in attention deficit hyperactivity disorder (ADHD), but the results have been inconsistent, potentially related to confounding medication effects. Furthermore, specific topological alterations in functional networks and their role in behavioral inhibition dysfunction remain to be established. Resting‐state functional magnetic resonance imaging was performed on 51 drug‐naïve children with ADHD and 55 age‐matched healthy controls. Brain functional networks were constructed by thresholding the partial correlation matrices of 90 brain regions, and graph theory was used to analyze network topological properties. The Stroop test was used to assess cognitive inhibitory abilities. Nonparametric permutation tests were used to compare the topological architectures in the two groups. Compared with healthy subjects, brain networks in ADHD patients demonstrated altered topological characteristics, including lower global (FDR q = 0.01) and local efficiency (p = 0.032, uncorrected) and a longer path length (FDR q = 0.01). Lower nodal efficiencies were found in the left inferior frontal gyrus and anterior cingulate cortex in the ADHD group (FDR both q < 0.05). Altered global and nodal topological efficiencies were associated with the severity of inhibitory cognitive control deficits and hyperactivity symptoms in ADHD (p <0 .05). Alterations in network topologies in drug‐naïve ADHD patients indicate weaker small‐worldization with decreased segregation and integration of functional brain networks. Deficits in the cingulo‐fronto‐parietal attention network were associated with inhibitory control deficits.     

Anomalous single‐subject based morphological cortical networks in drug‐naive,first‐episode major depressive disorder

Major depressive disorder (MDD) has been associated with disruptions in the topological organization of brain morphological networks in group‐level data. Such disruptions have not yet been identified in single‐patients, which is needed to show relations with symptom severity and to evaluate their potential as biomarkers for illness. To address this issue, we conducted a cross‐sectional structural brain network study of 33 treatment‐naive, first‐episode MDD patients and 33 age‐, gender‐, and education‐matched healthy controls (HCs). Weighted graph‐theory based network models were used to characterize the topological organization of brain networks between the two groups. Compared with HCs, MDD patients exhibited lower normalized global efficiency and higher modularity in their whole‐brain morphological networks, suggesting impaired integration and increased segregation of morphological brain networks in the patients. Locally, MDD patients exhibited lower efficiency in anatomic organization for transferring information predominantly in default‐mode regions including the hippocampus, parahippocampal gyrus, precuneus and superior parietal lobule, and higher efficiency in the insula, calcarine and posterior cingulate cortex, and in the cerebellum. Morphological connectivity comparisons revealed two subnetworks that exhibited higher connectivity strength in MDD mainly involving neocortex‐striatum‐thalamus‐cerebellum and thalamo‐hippocampal circuitry. MDD‐related alterations correlated with symptom severity and differentiated individuals with MDD from HCs with a sensitivity of 87.9% and specificity of 81.8%. Our findings indicate that single subject grey matter morphological networks are often disrupted in clinically relevant ways in treatment‐naive, first episode MDD patients. Circuit‐specific changes in brain anatomic network organization suggest alterations in the efficiency of information transfer within particular brain networks in MDD. Hum Brain Mapp 38:2482–2494, 2017. © 2017 Wiley Periodicals, Inc.     

Functional–structural relationship in large‐scale brain networks of patients with end stage renal disease after kidney transplantation: A longitudinal study

It is unclear how the brain network changed after kidney transplantation (KT). We explored the patterns of large‐scale complex network after KT in end‐stage renal disease (ESRD) patients with resting‐state functional MRI (rs‐fMRI) and diffusion tensor imaging (DTI). Twenty‐one ESRD patients (14 men; mean age, 31.5 ± 9.9 years) scheduled for KT and 17 age‐ and gender‐matched healthy controls (HC) (8 men; mean age, 28.9 ± 7.2 years) were enrolled in this study. Each participant underwent rs‐fMRI and DTI scans in three time points (pre‐KT, 1 and 6 months after KT [for ESRD]). Graph theory analysis was used to characterize the topological properties by using functional and structural network connectivities intergroup correlation analysis was performed between functional/structural MR indexes and clinical markers. Compared with HC, pre‐KT ESRD patients showed an altered topological organization in both functional and structural networks. Compared with pre‐KT, increased node degree and node efficiency were observed for both functional and structural networks at 1 month after KT (all p < .05), which were further increased at 6 months after KT (p < .05). Both functional and structural networks did not recover completely at 6 months after KT (all p < .05). The patients showed an increased functional–structural connectivity coupling at 1 month after KT compared with HC (p = .041). A trend of progressive recovery of functional and structural connectivity networks was observed in ERSD patients after KT, which did not recover to the normal levels even in 6 months after KT. The study results underlie cognitive function recovery in ESRD patients following KT in the neuropathophysiological perspective.     

Aberrant dynamic structure–function relationship of rich‐club organization in treatment‐naïve newly diagnosed juvenile myoclonic epilepsy

Neuroimaging studies have shown that juvenile myoclonic epilepsy (JME) is characterized by impaired brain networks. However, few studies have investigated the potential disruptions in rich‐club organization—a core feature of the brain networks. Moreover, it is unclear how structure–function relationships dynamically change over time in JME. Here, we quantify the anatomical rich‐club organization and dynamic structural and functional connectivity (SC–FC) coupling in 47 treatment‐naïve newly diagnosed patients with JME and 40 matched healthy controls. Dynamic functional network efficiency and its association with SC–FC coupling were also calculated to examine the supporting of structure–function relationship to brain information transfer. The results showed that the anatomical rich‐club organization was disrupted in the patient group, along with decreased connectivity strength among rich‐club hub nodes. Furthermore, reduced SC–FC coupling in rich‐club organization of the patients was found in two functionally independent dynamic states, that is the functional segregation state (State 1) and the strong somatomotor‐cognitive control interaction state (State 5); and the latter was significantly associated with disease severity. In addition, the relationships between SC–FC coupling of hub nodes connections and functional network efficiency in State 1 were found to be absent in patients. The aberrant dynamic SC–FC coupling of rich‐club organization suggests a selective influence of densely interconnected network core in patients with JME at the early phase of the disease, offering new insights and potential biomarkers into the underlying neurodevelopmental basis of behavioral and cognitive impairments observed in JME.     

The topological organization of white matter network in internet gaming disorder individuals

White matter (WM) integrity abnormalities had been reported in Internet gaming disorder (IGD). Diffusion tensor imaging (DTI) tractography allows identification of WM tracts, potentially providing information about the integrity and organization of relevant underlying WM fiber tracts’ architectures, which has been used to investigate the connectivity of cortical and subcortical structures in several brain disorders. Unfortunately, relatively little is known about the thoroughly circuit-level characterization of topological property changes of WM network with IGD. Sixteen right-hand adolescents with IGD participated in our study, according to the diagnostic criteria of IGD in DSM-5. Meanwhile, 16 age and gender-matched healthy controls were also enrolled. DTI tractography was employed to generate brain WM networks in IGD individuals and healthy controls. The 90 cortical and subcortical regions derived from AAL template were chosen as the nodes. The network parameters (i.e., Network strength, clustering coefficient, shortest path length, global efficiency, local efficiency, regional efficiency) were calculated and then correlated with the Internet addiction test (IAT) scores in IGD. IGD group showed decreased global efficiency, local efficiency and increased shortest path length. Further analysis revealed the reduced nodal efficiency in frontal cortex, anterior cingulate cortex and pallidium in IGD. In addition, the global efficiency of WM network was correlated with the IAT scores in IGD (r = ?0.5927; p = 0.0155). We reported the abnormal topological organization of WM network in IGD and the association with the severity of IGD, which may provide new insights into the neural mechanism of IGD from WM network level.