Neuroticism and conscientiousness respectively positively and negatively correlated with the network characteristic path length in dorsal lateral prefrontal cortex: A resting-state fNIRS study

AbstractIn perceptual multistability, the content of consciousness alternates spontaneously between different interpretations of unchanged sensory input. The source of these internally driven transitions in conscious perception is unknown. Here we show that transient, low frequency (1-9 Hz) perisynaptic bursts in the macaque lateral prefrontal cortex precede spontaneous perceptual transitions in a no-report binocular motion rivalry task. These low-frequency transients suppress 20-40 Hz oscillatory bursts that selectively synchronise the discharge activity of neuronal ensembles signalling conscious content. Similar ongoing state changes, with dynamics resembling the temporal structure of spontaneous perceptual alternations during rivalry, dominate the prefrontal cortex during resting-state, thus pointing to their default, endogenous nature. Our results suggest that prefrontal state fluctuations control access to consciousness through a reorganisation in the activity of feature-specific neuronal ensembles.One sentence summaryPrefrontal state transitions precede spontaneous transitions in the content of consciousness.

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Altered Small-World Functional Network Topology in Patients with Optic Neuritis: A Resting-State fMRI Study

Disease Markers ◽

10.1155/2021/9948751 ◽

2021 ◽

Vol 2021 ◽

pp. 1-9

Author(s):

Ke Song ◽

Juan Li ◽

Yuanqiang Zhu ◽

Fang Ren ◽

Lingcan Cao ◽

...

Keyword(s):

Resting State ◽

Path Length ◽

Small World ◽

Brain Network ◽

Clustering Coefficient ◽

Control Group ◽

Network Efficiency ◽

Characteristic Path Length ◽

Brain Functional Connectivity ◽

The Brain

Aim. This study investigated changes in small-world topology and brain functional connectivity in patients with optic neuritis (ON) by resting-state functional magnetic resonance imaging (rs-fMRI) and based on graph theory. Methods. A total of 21 patients with ON (8 males and 13 females) and 21 matched healthy control subjects (8 males and 13 females) were enrolled and underwent rs-fMRI. Data were preprocessed and the brain was divided into 116 regions of interest. Small-world network parameters and area under the integral curve (AUC) were calculated from pairwise brain interval correlation coefficients. Differences in brain network parameter AUCs between the 2 groups were evaluated with the independent sample t -test, and changes in brain connection strength between ON patients and control subjects were assessed by network-based statistical analysis. Results. In the sparsity range from 0.08 to 0.48, both groups exhibited small-world attributes. Compared to the control group, global network efficiency, normalized clustering coefficient, and small-world value were higher whereas the clustering coefficient value was lower in ON patients. There were no differences in characteristic path length, local network efficiency, and normalized characteristic path length between groups. In addition, ON patients had lower brain functional connectivity strength among the rolandic operculum, medial superior frontal gyrus, insula, median cingulate and paracingulate gyri, amygdala, superior parietal gyrus, inferior parietal gyrus, supramarginal gyrus, angular gyrus, lenticular nucleus, pallidum, superior temporal gyrus, and cerebellum compared to the control group ( P < 0.05 ). Conclusion. Patients with ON show typical “small world” topology that differed from that detected in HC brain networks. The brain network in ON has a small-world attribute but shows reduced and abnormal connectivity compared to normal subjects and likely causes symptoms of cognitive impairment.

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Functional network topology in drug resistant and well-controlled idiopathic generalized epilepsy: a resting state functional MRI study

Brain Communications ◽

10.1093/braincomms/fcab196 ◽

2021 ◽

Vol 3 (3) ◽

Author(s):

Emily J Pegg ◽

Andrea McKavanagh ◽

R Martyn Bracewell ◽

Yachin Chen ◽

Kumar Das ◽

...

Keyword(s):

Network Topology ◽

Resting State ◽

Betweenness Centrality ◽

Path Length ◽

Seizure Control ◽

Drug Resistant ◽

Idiopathic Generalized Epilepsy ◽

Characteristic Path Length ◽

Graph Theoretic ◽

Generalized Epilepsy

Abstract Despite an increasing number of drug treatment options for people with idiopathic generalized epilepsy (IGE), drug resistance remains a significant issue and the mechanisms underlying it remain poorly understood. Previous studies have largely focused on potential cellular or genetic explanations for drug resistance. However, epilepsy is understood to be a network disorder and there is a growing body of literature suggesting altered topology of large-scale resting networks in people with epilepsy compared with controls. We hypothesize that network alterations may also play a role in seizure control. The aim of this study was to compare resting state functional network structure between well-controlled IGE (WC-IGE), drug resistant IGE (DR-IGE) and healthy controls. Thirty-three participants with IGE (10 with WC-IGE and 23 with DR-IGE) and 34 controls were included. Resting state functional MRI networks were constructed using the Functional Connectivity Toolbox (CONN). Global graph theoretic network measures of average node strength (an equivalent measure to mean degree in a network that is fully connected), node strength distribution variance, characteristic path length, average clustering coefficient, small-world index and average betweenness centrality were computed. Graphs were constructed separately for positively weighted connections and for absolute values. Individual nodal values of strength and betweenness centrality were also measured and ‘hub nodes’ were compared between groups. Outcome measures were assessed across the three groups and between both groups with IGE and controls. The IGE group as a whole had a higher average node strength, characteristic path length and average betweenness centrality. There were no clear differences between groups according to seizure control. Outcome metrics were sensitive to whether negatively correlated connections were included in network construction. There were no clear differences in the location of ‘hub nodes’ between groups. The results suggest that, irrespective of seizure control, IGE interictal network topology is more regular and has a higher global connectivity compared to controls, with no alteration in hub node locations. These alterations may produce a resting state network that is more vulnerable to transitioning to the seizure state. It is possible that the lack of apparent influence of seizure control on network topology is limited by challenges in classifying drug response. It is also demonstrated that network topological features are influenced by the sign of connectivity weights and therefore future methodological work is warranted to account for anticorrelations in graph theoretic studies.

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Potential Locations for Non-Invasive Brain Stimulation in Treating Schizophrenia: A Resting-State Functional Connectivity Analysis

Frontiers in Neurology ◽

10.3389/fneur.2021.766736 ◽

2021 ◽

Vol 12 ◽

Author(s):

Yanzhe Ning ◽

Sisi Zheng ◽

Sitong Feng ◽

Binlong Zhang ◽

Hongxiao Jia

Keyword(s):

Prefrontal Cortex ◽

Functional Connectivity ◽

Brain Stimulation ◽

Resting State ◽

Regions Of Interest ◽

Connectivity Analysis ◽

Resting State Functional Connectivity ◽

Lateral Prefrontal Cortex ◽

Non Invasive ◽

Brain Surface

Introduction: Non-invasive brain stimulation (NIBS) techniques have been widely used for the purpose of improving clinical symptoms of schizophrenia. However, the ambiguous stimulation targets may limit the efficacy of NIBS for schizophrenia. Exploring effective stimulation targets may improve the clinical efficacy of NIBS in schizophrenia.Methods: We first conducted a neurosynth-based meta-analysis of 715 functional magnetic resonance imaging studies to identify schizophrenia-related brain regions as regions of interest. Then, we performed the resting-state functional connectivity analysis in 32 patients with first-episode schizophrenia to find brain surface regions correlated with the regions of interest in three pipelines. Finally, the 10–20 system coordinates corresponding to the brain surface regions were considered as potential targets for NIBS.Results: We identified several potential targets of NIBS, including the bilateral dorsal lateral prefrontal cortex, supplementary motor area, bilateral inferior parietal lobule, temporal pole, medial prefrontal cortex, precuneus, superior and middle temporal gyrus, and superior and middle occipital gyrus. Notably, the 10-20 system location of the bilateral dorsal lateral prefrontal cortex was posterior to F3 (F4), not F3 (F4).Conclusion: Conclusively, our findings suggested that the stimulation locations corresponding to these potential targets might help clinicians optimize the application of NIBS therapy in individuals with schizophrenia.

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Altered small-world functional network topology in patients with optic neuritis: A resting- state fMRI study

10.1101/2020.06.09.141432 ◽

2020 ◽

Cited By ~ 2

Author(s):

Ke Song ◽

Juan Li ◽

Yuanqiang Zhu ◽

Fang Ren ◽

Lingcan Cao ◽

...

Keyword(s):

Resting State ◽

Path Length ◽

Small World ◽

Brain Network ◽

Clustering Coefficient ◽

Control Group ◽

Network Efficiency ◽

Characteristic Path Length ◽

Brain Functional Connectivity ◽

The Brain

AbstractPurposeThis study investigated changes in small-world topology and brain functional connectivity in patients with optic neuritis (ON) by resting-state functional magnetic resonance imaging (rs-fMRI) and based on graph theory.MethodsA total of 21 patients with ON (8 males and 13 females) and 21 matched healthy control subjects (8 males and 13 females) were enrolled at the First Affiliated Hospital of Nanchang University and underwent rs-fMRI. Data were preprocessed and the brain was divided into 116 regions of interest. Small-world network parameters and area under the integral curve (AUC) were calculated from pairwise brain interval correlation coefficients. Differences in brain network parameter AUCs between the 2 groups were evaluated with the independent sample t-test, and changes in brain connection strength between ON patients and control subjects were assessed by network-based statistical analysis.ResultsIn the sparsity range from 0.08 to 0.48, both groups exhibited small-world attributes.Compared to the control group, global network efficiency, normalized clustering coefficient, and small-world value were higher whereas the clustering coefficient value was lower in ON patients. There were no differences in characteristic path length, local network efficiency, and normalized characteristic path length between groups. In addition, ON patients had lower brain functional connectivity strength among the rolandic operculum, medial superior frontal gyrus, insula, median cingulate and paracingulate gyri, amygdala, superior parietal gyrus, inferior parietal gyrus, supramarginal gyrus, angular gyrus, lenticular nucleus, pallidum, superior temporal gyrus, cerebellum_Crus1_L, and left cerebellum_Crus6_L compared to the control group (P < 0.05).ConclusionThe brain network in ON has a small-world attributes but shows reduced and abnormal connectivity compared to normal subjects. These findings provide a further insight into the neural pathogenesis of ON and reveal specific fMRI findings that can serve as diagnostic and prognostic indices.

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