Connection Of Subsystems Research Articles

Reduced resting-state functional connectivity of default mode network subsystems in patients with obsessive-compulsive disorder

ObjectivesNeuroimaging studies have reported extensive resting-state functional connectivity (rsFC) abnormalities in the default mode network (DMN) in patients with obsessive-compulsive disorder (OCD), but findings are inconsistent. DMN can be divided into three subsystems: core, dorsal medial prefrontal cortex (dMPFC), and medial temporal lobe (MTL). This study aimed to explore abnormalities in rsFC strength within and between DMN subsystems in OCD patients, and their relationship with clinical symptoms. MethodsThis study recruited 39 OCD patients and 45 healthy controls (HCs). OCD symptoms were assessed using the Yale-Brown Obsessive-Compulsive Scale (YBOCS). The seed-to-seed method was used to construct rsFC matrix. The rsFC strength within and between the three DMN subsystems were calculated. ResultsCompared to the HC group, the OCD group exhibited reduced rsFC strength within core subsystem (F = 7.799, p = 0.007, Bonferroni corrected p = 0.042). Further, this reduction was also observed in the unmedicated OCD group (n = 19), but not in the medicated OCD group (n = 18). In addition, rsFC strength within core subsystem was negatively correlated with the obsession subscale of YBOCS in the OCD group (r = −0.512, p = 0.004, Bonferroni corrected p = 0.008). Further, this correlation was also significant in the unmedicated OCD group, but not in the medicated OCD group. ConclusionsOur findings suggest that reduced rsFC strength within core subsystem is a feature of OCD patients and may serve as a potential biomarker of obsession severity. Moreover, pharmacological treatments may affect rsFC strength in DMN.

Roles of the Default Mode Network in Different Aspects of Self-representation When Remembering Social Autobiographical Memories.

Autobiographical memory (AM) is episodic memory for personally experienced events, in which self-representation is more important than that in laboratory-based memory. Theoretically, self-representation in a social context is categorized as the interpersonal self (IS) referred to in a social interaction with a person or the social-valued self (SS) based on the reputation of the self in the surrounding society. Although functional neuroimaging studies have demonstrated the involvement of the default mode network (DMN) in self-representation, little is known about how the DMN subsystems contribute differentially to IS-related and SS-related AMs. To elucidate this issue, we used fMRI to scan healthy young adults during the recollection of AMs. We performed multivariate pattern analysis (MVPA) and assessed functional connectivity in the DMN subsystems: the midline core, medial temporal lobe (MTL), and dorsomedial pFC (dmPFC) subsystems. The study yielded two main sets of findings. First, MVPA revealed that all DMN subsystems showed significant classification accuracy between IS-related and nonsocial-self-related AMs, and IS-related functional connectivity of the midline core regions with the retrosplenial cortex of the MTL subsystem and the dmPFC of the dmPFC subsystem was significant. Second, MVPA significantly distinguished between SS-related and nonsocial-self-related AMs in the midline core and dmPFC subsystems but not in the MTL subsystem, and SS-related functional connectivity with the midline core regions was significant in the temporal pole and TPJ of the dmPFC subsystem. Thus, dissociable neural mechanisms in the DMN could contribute to different aspects of self-representation in social AMs.

Effective Connectivity of Default Mode Network Subsystems in Parkinson’s Disease with Mild Cognitive Impairment Based on Spectral Dynamic Causal Modeling

Effective Connectivity of Default Mode Network Subsystems in Parkinson’s Disease with Mild Cognitive Impairment Based on Spectral Dynamic Causal Modeling

Quadratic stability of uncertain large-scale networked systems

In this paper, the quadratic stability of continuous-time uncertain large-scale networked systems is considered. The systems are composed of many subsystems distributed in different locations in space and interconnected according to a certain network topology. A computationally efficient sufficient condition for the quadratic stability of large-scale networked systems is established, utilising effectively the block diagonal structure of the system parameter matrix and the sparseness of the subsystem connection matrix (SCM). Furthermore, a stability condition is presented, which is entirely contingent on the parameters of each subsystem. The simulation results show that the obtained conditions have obvious advantages in analysing the quadratic stability of large-scale networked systems.

(Q, S, R)-Dissipativity Analysis of Large-Scale Networked Systems

This brief investigates the (Q,S,R)-dissipativity of large-scale networked systems in the discrete-time case. The networked system consists of a large number of subsystems, each of which can have different dynamic characteristics, and the connections among subsystems are arbitrary. When the number of subsystems is large, the traditional analysis method based on lumped description may have computational difficulties. To solve this problem, some computationally attractive conditions are derived, which essentially depend on the block-diagonal structure of the system parameter matrices and the sparseness of the subsystem connection matrix. Numerical simulations illustrate that compared with the existing results, the conditions suggested in this brief have higher computational efficiency in the dissipative analysis of large-scale networked systems.

State efficiency estimation method in the road and transport environment according to the criterion of "zero death"

Considered in the article, the method for assessing the effectiveness of conditions in the road transport environment according to the criterion of "zero mortality" in road accidents is aimed at developing an effective approach and targeted actions in the field of ensuring road safety in road transport. The necessity of a systematic approach to ensure the audit of places of concentration of road accidents is substantiated. A conceptual model of an information system and the fact of an accident event as a mass event in a complex road and transport environment has been developed, which includes interacting connections of subsystems, factors of an emergency situation, the causes of an accident in the system "road user—vehicle—road—environment". An information system has been developed to reduce the impact of negative factors in the occurrence of road accidents in DTS. Combinations of possible variants of RTA and mutually exclusive properties of the information states of the environment are determined. Keywords: road safety, systems approach, complex system, zero mortality, traffic accident

Numerical and experimental investigation on autoparametric resonance of multi-system structures

The analysis of dynamic stability in frame structures has always been a critical issue in engineering and mechanical design. Autoparametric resonance instability problems present a more complex dynamic instability mechanism than general parametric resonance, and determining the unstable regions of frame structures with multiple subsystems requires consideration of the coupled vibration of each subsystem. Unfortunately, existing approximate formulas are inadequate to analyze the stable boundary of autoparametric resonance in frame structures. To address this issue, this paper proposes a novel method called the dynamic axial force transfer coefficient (DTC) method to investigate the spatial dynamic instability characteristics of complex frame structures under parametric excitation due to autoparametric resonance. The proposed method, in conjunction with the harmonic balance method and the finite element method (FEM), established the global finite element equation of the frame and derived the stable boundary equation of autoparametric resonance for general frame structures. A complex spatial frame model is built to verify the effectiveness of the DTC method, and a comprehensive parametric analysis is conducted to investigate the dynamic instability mechanism of autoparametric resonance, including structural damping, static load coefficient, connection and boundary conditions of subsystems, and cross-sectional dimensions of subsystems. The results show that autoparametric resonance stability analysis of frame structures should consider the design parameters of each subsystem independently. In addition, strong coupling interaction between subsystems may induce autoparametric internal resonance of structure subjected to dynamic load. An autoparametric resonance test of a Γ-shaped frame is presented to further verify the proposed method. The test reveals the mechanism of the strong coupling effect, which may lead to a high risk of structural failure. More importantly, the DTC method can accurately determine the unstable boundary of multi-system frame structures, which is consistent with conventional methods (EGE) and experimental results, and predict the strong coupling effect of practical structures. The proposed method is simpler and more convenient than the existing methods for stability analysis of the autoparametric resonance of general frame structures, and can provide more effective guidance for structural design.

Functional disconnection between subsystems of the default mode network in bipolar disorder

BackgroundDisruption in connectivity between default mode network (DMN) regions has previously been reported in bipolar disorder (BD). The current study aimed to investigate the dysfunction of the DMN subsystem in patients with BD during manic and depressive episodes and to explore its relationship with the symptoms of BD. MethodsFifty-two patients with bipolar disorder and 39 healthy controls were recruited. Eleven seed points were selected from three DMN subsystems. We performed seed-based resting-state functional connectivity (FC) analysis and obtained individual DMN FC matrices by computing the spatial correlations between pairs of FC maps. The strength of the connections within and between the three DMN subsystems, including the core subsystem, dorsal medial prefrontal cortex subsystem, and medial temporal lobe (MTL) subsystem, was used for group analyses. ResultsCompared with healthy controls, reduced FC between the core and MTL subsystem was observed in BD patients, especially in those with depressive episodes, but not in those with manic episodes. There were significant differences in core-MTL connectivity strength between the two patient groups during manic and depressive episodes. Moreover, core-MTL subsystem connectivity was negatively correlated with the depression scale. The FC within the core subsystem was negatively correlated with anxiety and negatively correlated with depression. ConclusionThis study provides evidence for an abnormal default network subsystem connection in bipolar disorder during manic and depressive episodes, revealing the neuropathological mechanism of the disease from the perspective of brain functional connectivity.

Stability analysis of spatially interconnected systems with signal saturation

The robust stability problem of spatially interconnected systems with signal saturation among the many composed subsystems is considered. The system structure is usually sparse, and each subsystem has different dynamics. Firstly, a robust stability condition is established based on integral quadratic constraint (IQC) theory, which makes full use of the sparseness of the subsystem connection topology. Secondly, a decoupling robust condition that only depends on the subsystem parameters is proved. Finally, it is shown through numerical simulations that the obtained conditions are computationally valid in analyzing spatially interconnected systems with signal saturation constraints among the subsystems.

Functional connectivity of the default mode network subsystems in patients with major depressive episodes with mixed features

BackgroundThe neuroimaging mechanism of major depressive episodes with mixed features (MMF) is not clear.AimsThis study aimed to investigate the functional connectivity of the default mode network (DMN) subsystems among patients...

Role of cinematography in anticorruption enlightenment: global experience

Objective: to conduct a comprehensive interdisciplinary legal study of the role of cinematography in anti-corruption enlightenment of citizens.Methods: a structural and functional approach to the interpretation of society as a connection of subsystems, in which cinematography is a part of the cultural subsystem, while anti-corruption policy refers simultaneously to the public subsystem (enlightenment) and the state subsystem (politics). The chosen approach determines a set of specific research methods, such as a critical analysis of theoretical literature on corruption behavior and on the relationship between a viewer and a cinematography product in conjunction with an empirical study of various cases in the form of films and film projects devoted to anti-corruption topics.Results: the analysis of the mechanisms of building the relationships between a viewer and cinematography allowed identifying the possibilities of cinematography to have a long-term impact on a viewer, due not only to the technical capabilities of cinematography, but also to the psychobiological mechanisms of man. By the example of specific projects, the expediency of using cinema as an anti-corruption enlightenment tool was proved and justified. In particular, if the relevant messages are laid in the plot of a feature film, then, thanks to mirror neurons and human thinking mechanisms, they can serve educational purposes and demonstrate the consequences of corrupt behavior. It is important not to intimidate the audience with the horrors of living with corruption, but to show a positive way out and scenarios of living without it. This can lead to an increase in civic engagement, to an increase in interest in the issue under discussion, as well as to an increase in ratings of trust in the state.Scientific novelty: the article proves the inexpediency of evaluating cinema solely as a form of entertainment, and for the first time examines examples of the practical application of cinema for anti-corruption policy and enlightenment by comparing approaches used in different countries.Practical significance: the main conclusions of the article can be used in scientific, pedagogical and practical activities when developing long-term strategies and programs of anti-corruption enlightenment, as well as in the framework of cinematographic activities to assess the long-term consequences of the demonstrated film narrative.

Constructibility of a causal/impulse free NDS using descriptor form subsystems

Requirements are investigated in this paper for each descriptor form subsystem, with which a causal/impulse free networked dynamic system (NDS) can be constructed. For this purpose, a matrix rank based necessary and sufficient condition is at first derived for the causality/impulse freeness of an NDS, in which the associated matrix depends affinely on subsystem connections. From this result, a necessary and sufficient condition is derived for each subsystem, such that there exists a subsystem connection matrix that leads to a causal/impulse free NDS. This condition further leads to a necessary and sufficient condition for the existence of a local static output feedback that guarantees the construction of a causal/impulse free NDS. A prominent property of these conditions are that all the involved numerical computations are performed independently on each individual subsystem, which is quite attractive in reducing computation costs and improving numerical stability for large scale NDS analysis and synthesis. Situations have also been clarified in which NDS causality/impulse freeness is independent of subsystem connections. It has also been made clear that under some situations, local static output feedbacks are not helpful in constructing a causal NDS.

Developmental Disruption of Erbb4 in Pet1+ Neurons Impairs Serotonergic Sub-System Connectivity and Memory Formation.

The serotonergic system of mammals innervates virtually all the central nervous system and regulates a broad spectrum of behavioral and physiological functions. In mammals, serotonergic neurons located in the rostral raphe nuclei encompass diverse sub-systems characterized by specific circuitry and functional features. Substantial evidence suggest that functional diversity of serotonergic circuits has a molecular and connectivity basis. However, the landscape of intrinsic developmental mechanisms guiding the formation of serotonergic sub-systems is unclear. Here, we employed developmental disruption of gene expression specific to serotonergic subsets to probe the contribution of the tyrosine kinase receptor ErbB4 to serotonergic circuit formation and function. Through an in vivo loss-of-function approach, we found that ErbB4 expression occurring in a subset of serotonergic neurons, is necessary for axonal arborization of defined long-range projections to the forebrain but is dispensable for the innervation of other targets of the serotonergic system. We also found that Erbb4-deletion does not change the global excitability or the number of neurons with serotonin content in the dorsal raphe nuclei. In addition, ErbB4-deficiency in serotonergic neurons leads to specific behavioral deficits in memory processing that involve aversive or social components. Altogether, our work unveils a developmental mechanism intrinsically acting through ErbB4 in subsets of serotonergic neurons to orchestrate a precise long-range circuit and ultimately involved in the formation of emotional and social memories.

Effects of escitalopram therapy on resting-state functional connectivity of subsystems of the default mode network in unmedicated patients with major depressive disorder

Antidepressants are often the first-line medications prescribed for patients with major depressive disorder (MDD). Given the critical role of the default mode network (DMN) in the physiopathology of MDD, the current study aimed to investigate the effects of antidepressants on the resting-state functional connectivity (rsFC) within and between the DMN subsystems. We collected resting-state functional magnetic resonance imaging (rs-fMRI) data from 36 unmedicated MDD patients at baseline and after escitalopram treatment for 12 weeks. The rs-fMRI data were also collected from 61 matched healthy controls at the time point with the same interval. Then, we decomposed the DMN into three subsystems based on a template from previous studies and computed the rsFC within and between the three subsystems. Finally, repeated measures analysis of covariance was conducted to identify the main effect of group and time and their interaction effect. We found that the significantly reduced within-subsystem rsFC in the DMN core subsystem in patients with MDD at baseline was increased after escitalopram treatment and became comparable with that in the healthy controls, whereas the reduced within-subsystem rsFC persisted in the DMN dorsal medial prefrontal cortex (dMPFC) and medial temporal subsystems in patients with MDD following escitalopram treatment. In addition, the reduced between-subsystem rsFC between the core and dMPFC subsystem showed a similar trend of change after treatment in patients with MDD. Moreover, our main results were confirmed using the DMN regions from another brain atlas. In the current study, we found different effects of escitalopram on the rsFC of the DMN subsystems. These findings deepened our understanding of the neuronal basis of antidepressants’ effect on brain function in patients with MDD. The trial name: appropriate technology study of MDD diagnosis and treatment based on objective indicators and measurement. URL: http://www.chictr.org.cn/showproj.aspx?proj=21377. Registration number: ChiCTR-OOC-17012566.

Study on FE-SEA Modeling and Acoustic Performance of Heavy Duty Commercial Vehicle Based on Experimental Statistical Energy Parameters

Due to the difficulty of obtaining statistical energy parameters of complex structures and the complexity of modeling connection and model verification, the hybrid FE-SEA model has many problems in modeling complex structures. Therefore, in order to solve the above problems, this paper provides a reference for the application of the hybrid FE-SEA model in complex structures. In this paper, the hybrid FE-SEA commercial vehicle model is established by an experimental statistical energy parameter modeling method and a modification method. The model division and subsystem connection modeling of a complex substructure of a heavy vehicle cab are studied. In the hybrid model, the hybrid line connection and the hybrid point connection are established. On this basis, the parameters of the cab model were studied, and the statistical energy parameters such as modal density, internal loss factor, and coupling loss factor were obtained by the experimental method. The statistical energy parameters of the cab acoustic model are modified. Finally, the accuracy of the model is verified by vehicle test. In addition, the acoustic performance of the cab was optimized, and airtightness and acoustic packaging were verified. The full parameter modeling and correction method is adopted in this paper, which is an effective supplement to the traditional statistical energy parameter modeling method.

The aquaponic principle—It is all about coupling

AbstractThe aquaponic principle is the coupling of animal aquaculture (e.g. fish) with plant production (e.g. vegetables) for saving resources. At present, various definitions of aquaponics exist, some bearing the risk of misinterpretation by dismissing the original meaning or being contradictory. In addition, there is no standard terminology for the aspects of coupling between the aquaponic subsystems. In this study, we addressed both issues. (1) We developed new or revised definitions that are summarised by: Aquaponic farming comprises aquaponics (which couples tank‐based animal aquaculture with hydroponics) and trans‐aquaponics, which extends aquaponics to tankless aquaculture as well as non‐hydroponics plant cultivation methods. Within our conceptual system, the term aquaponics corresponds to the definitions of FAO and EU. (2) A system analysis approach was utilised to explore different aquaponic setups aiming to better describe the way aquaponic subsystems are connected. We introduced the new terms ‘coupling type’ and ‘coupling degree’, where the former qualitatively characterises the water‐mediated connections of aquaponic subsystems. A system with on‐demand nutrient water supply for the independent operating plant cultivation is an ‘on‐demand coupled system’ and we propose to deprecate the counterintuitive term ‘decoupled system’ for this coupling type. The coupling degree comprises a set of parameters to quantitatively determine the coupling's efficiency of internal streams, for example, water and nutrients. This new framework forms a basis for improved communication, provides a uniform metric for comparing aquaponic facilities, and offers criteria for facility optimisation. In future system descriptions, it will simplify evaluation of the coupling's contribution to sustainability of aquaponics.

A Revisit to the Controllability and Observability of Networked Dynamic Systems

In this article, the controllability and observability of a general networked dynamic system (NDS) are reinvestigated. While some computationally efficient conditions have been established in previous works, difficulties arise when a full normal rank condition is not satisfied for some subsystems. To address this problem, the subsystem connection topology of the NDS is utilized and a sufficient and necessary condition is derived for its controllability and observability in this article. It is observed that the effects of the transmission zeros and the uncontrollable/unobservable modes of subsystems should be eliminated by subsystem connections to guarantee the controllability/observability of an NDS. Moreover, a sufficient condition and a necessary condition are provided for constructing controllable/observable NDSs in the view of subsystem connection topology and subsystem internal input/output signal, respectively. Finally, the sensor placement of a mechanical system is discussed, which shows the effectiveness of our results.

Cognitive impairment in Parkinson's disease is associated with Default Mode Network subsystem connectivity and cerebrospinal fluid Aβ

IntroductionTo identify clinically implementable biomarkers of cognitive impairment in Parkinson's Disease (PD) derived from resting state-functional MRI (rs-fMRI) and CSF protein analysis. MethodsIn this single-center longitudinal cohort study, we analyzed rs-fMRI and CSF biomarkers from 50 PD patients (23 cognitively normal, 18 mild cognitive impairment, 9 dementia) and 19 controls, who completed comprehensive neuropsychological testing. A subgroup of participants returned for follow-up cognitive assessments three years later. From rs-fMRI, we studied the connectivity within two distinct Default Mode Network subsystems: left-to-right hippocampus (LHC-RHC) and medial prefrontal cortex-to-posterior cingulate cortex (mPFC-PCC). We used regression analyses to determine whether imaging (LHC-RHC, mPFC-PCC), clinical (CSF Aβ-42:40, disease duration), and demographic (age, sex, education) variables were associated with global and domain-specific cognitive impairments. ResultsLHC-RHC (F3,67 = 3.41,p=0.023) and CSF Aβ-42:40 (χ2(3) = 8.77,p = 0.033) were reduced across more cognitively impaired PD groups. Notably, LHC-RHC connectivity was significantly associated with all global and domain-specific cognitive impairments (attention/executive, episodic memory, visuospatial, and language) at the baseline visit. In an exploratory longitudinal analysis, mPFC-PCC was associated with future global and episodic memory impairment. ConclusionWe used biomarker techniques that are readily available in clinical and research facilities to shed light on the pathophysiologic basis of cognitive impairment in PD. Our findings suggest that there is a functionally distinct role of the hippocampal subsystem within the DMN resting state network, and that intrinsic connectivity between the hippocampi is critically related to a broad range of cognitive functions in PD.

Reduced functional connectivity of default mode network subsystems in depression: Meta-analytic evidence and relationship with trait rumination

Resting-state functional connectivity changes in the default mode network (DMN) of patients with major depressive disorder (MDD) have been linked to rumination. The DMN is divided into three subsystems: a midline Core, a dorsal medial prefrontal cortex (DMPFC) subsystem, and a medial temporal lobe (MTL) subsystem. We examined resting-state functional connectivity within and between DMN subsystems in MDD and its association with rumination. First, we conducted a meta-analysis on a large multi-site dataset of 618 MDD and 683 controls to quantify the differences in DMN subsystem functional connectivity between MDD and controls. Second, we tested the association of DMN subsystem functional connectivity and rumination in a sample of 115 unmedicated participants with symptoms of anxiety/depression and 48 controls.In our meta-analysis, only functional connectivity in the DMN Core was significantly reduced in MDD compared to controls (g = −0.246, CI = [−0.417; −0.074], pFDR = 0.048). Functional connectivity in the DMPFC subsystem and between the Core and DMPFC subsystems was slightly reduced but not significantly (g = −0.162, CI = [−0.310; −0.013], pFDR = 0.096; g = −0.249, CI = [−0.464; −0.034], pFDR = 0.084). Results were heterogeneous across sites for connectivity in the Core and between Core and DMPFC (I2 = 0.348 and I2 = 0.576 respectively). Prediction intervals consistently encompassed 0. In the independent sample we collected, functional connectivity within the DMN Core, DMPFC and between Core and DMPFC was not reduced in MDD compared to controls (all pFDR > 0.05). Trait rumination did not predict connectivity within and between DMN subsystems (all pFDR > 0.05).We conclude that MDD as a diagnostic category shows slightly reduced functional connectivity within the DMN Core, independent of illness duration, treatment, symptoms and trait rumination. However, this effect is small, highly variable and heterogeneous across samples, so that we could only detect it at the meta-analytic level, with a sample size of several hundreds. Our results indicate that reduced Core DMN connectivity has significant limitations as a potential clinical or prognostic marker for the diagnosis of MDD and might be more relevant to consider as a characteristic distinguishing a subgroup of individuals within this diagnostic category.

Functional disconnection between subsystems of the default mode network in schizophrenia.

A dysfunctional default mode network (DMN) has been reported in patients with schizophrenia. However, the stability of the deficits has not been determined across different stages of the disorder. We examined the functional connectivity of the DMN subsystems of 125 patients with first-episode schizophrenia (FES) or recurrent schizophrenia (RES), compared to that of 82 healthy controls. We tested the robustness of the findings in an independent cohort of 158 patients and 39 healthy controls. We performed resting-state functional connectivity analysis, and examined the strength of the connections within and between the three subsystems of the DMN (core, dorsal medial prefrontal cortex [dMPFC], and medial temporal lobe [MTL]). We also analyzed the connectivity correlations to symptoms and illness duration. We found reduced connectivity strength between the core and MTL subsystems in schizophrenia patients compared to controls, with no differences between the FES and RES patient groups; these findings were validated in the second sample. Schizophrenia patients also showed a significant reduction in connectivity within the MTL and between the dMPFC-MTL subsystems, similarly between FES and RES groups. The connectivity strength within the core subsystem was negatively correlated with clinical symptoms in schizophrenia. There was no significant correlation between the DMN subsystem connectivity and illness duration. DMN subsystem connectivity deficits are present in schizophrenia, and the homochronicity of their appearance indicates the trait-like nature of these alterations. The DMN deficit may be useful for early diagnosis, and MTL dysfunction may be a crucial mechanism underlying schizophrenia.