On Stability and Inverse Optimality for a Class of Multi-agent Linear Consensus Protocols

Lee, Keun Uk; Lee, Jae Young; Choi, Yoon Ho; Park, Jin Bae

doi:10.1007/s12555-016-0723-1

Cited by 6 publications

(2 citation statements)

References 18 publications

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“…Generally, the FC of a brain shows the interactions between different brain regions, that is, the observed temporal correlations between spatially distant neurophysiological actions (Friston, 1994). Observations are mapped onto the connectome that reflects the heritable individual differences in the brain organization, which makes the connectivity-based approach that is promising for biometric (Finn et al, 2015; Lee et al, 2018; Pinti et al, 2018b). In this study, the FC analysis was divided into two parts: (i) An analysis of the initial RS phase of 4 min and (ii) a second experimental session of the WM task.…”

Section: Methodsmentioning

confidence: 99%

Effects of Acupuncture Therapy on MCI Patients Using Functional Near-Infrared Spectroscopy

Ghafoor

Lee

Hong

et al. 2019

Front. Aging Neurosci.

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Acupuncture therapy (AT) is a non-pharmacological method of treatment that has been applied to various neurological diseases. However, studies on its longitudinal effect on the neural mechanisms of patients with mild cognitive impairment (MCI) for treatment purposes are still lacking in the literature. In this clinical study, we assess the longitudinal effects of ATs on MCI patients using two methods: (i) Montreal Cognitive Assessment test (MoCA-K, Korean version), and (ii) the hemodynamic response (HR) analyses using functional near-infrared spectroscopy (fNIRS). fNIRS signals of a working memory (WM) task were acquired from the prefrontal cortex. Twelve elderly MCI patients and 12 healthy people were recruited as target and healthy control (HC) groups, respectively. Each group went through an fNIRS scanning procedure three times: The initial data were obtained without any ATs, and subsequently a total of 24 AT sessions were conducted for MCI patients (i.e., MCI-0: the data prior to ATs, MCI-1: after 12 sessions of ATs for 6 weeks, MCI-2: another 12 sessions of ATs for 6 weeks). The mean HR responses of all MCI-0–2 cases were lower than those of HCs. To compare the effects of AT on MCI patients, MoCA-K results, temporal HR data, and spatial activation patterns (i.e., t -maps) were examined. In addition, analyses of functional connectivity (FC) and graph theory upon WM tasks were conducted. With ATs, (i) the averaged MoCA-K test scores were improved (MCI-1, p = 0.002; MCI-2, p = 2.9 e –4 ); (ii) the mean HR response of WM tasks was increased ( p < 0.001); and (iii) the t -maps of MCI-1 and MCI-2 were enhanced. Furthermore, an increased FC in the prefrontal cortex in both MCI-1/MCI-2 cases in comparison to MCI-0 was obtained ( p < 0.01), and an increasing trend in the graph theory parameters was observed. All these findings reveal that ATs have a positive impact on improving the cognitive function of MCI patients. In conclusion, ATs can be used as a therapeutic tool for MCI patients as a non-pharmacological method (Clinical trial registration number: KCT 0002451 https://cris.nih.go.kr/cris/en/ ).

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Section: Methodsmentioning

confidence: 99%

Effects of Acupuncture Therapy on MCI Patients Using Functional Near-Infrared Spectroscopy

Ghafoor

Lee

Hong

et al. 2019

Front. Aging Neurosci.

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“…A starting threshold value of 0.5 was selected because it defines the connection strength among the channels, in order to ensure that the Pearson correlation coefficients are statistically significant. According to the matrix representation of the graphs, each matrix exactly defines a binary and undirected graph [73,74]. For analyzing the network, we computed the most commonly used metrics: connection density, global and nodal degree, nodal efficiency, global clustering coefficient, and network global efficiency [75].…”

Section: Hd-tdcs Stimulation Was Delivered By a Battery-drivenmentioning

confidence: 99%

Effects of HD‐tDCS on Resting‐State Functional Connectivity in the Prefrontal Cortex: An fNIRS Study

2018

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Functional connectivity is linked to several degenerative brain diseases prevalent in our aging society. Electrical stimulation is used for the clinical treatment and rehabilitation of patients with many cognitive disorders. In this study, the effects of high-definition transcranial direct current stimulation (HD-tDCS) on resting-state brain networks in the human prefrontal cortex were investigated by using functional near-infrared spectroscopy (fNIRS). The intrahemispheric as well as interhemispheric connectivity changes induced by 1 mA HD-tDCS were examined in 15 healthy subjects. Pearson correlation coefficient-based correlation matrices were generated from filtered time series oxyhemoglobin (ΔHbO) signals and converted into binary matrices. Common graph theory metrics were computed to evaluate the network changes. Systematic interhemispheric, intrahemispheric, and intraregional connectivity analyses demonstrated that the stimulation positively affected the resting-state connectivity in the prefrontal cortex. The poststimulation connectivity was increased throughout the prefrontal region, while focal HD-tDCS effects induced an increased rate of connectivity in the stimulated hemisphere. The graph theory metrics clearly distinguished the prestimulation and poststimulation networks for a range of thresholds. The results of this study suggest that HD-tDCS can be used to increase functional connectivity in the prefrontal cortex. The increase in functional connectivity can be explored clinically for neurorehabilitation of patients with degenerative brain diseases.

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Optimal Consensus Control for Heterogeneous Nonlinear Multiagent Systems with Partially Unknown Dynamics

Wang¹,

Li³

et al. 2019

Int. J. Control Autom. Syst.

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On Stability and Inverse Optimality for a Class of Multi-agent Linear Consensus Protocols

Cited by 6 publications

References 18 publications

Effects of Acupuncture Therapy on MCI Patients Using Functional Near-Infrared Spectroscopy

Effects of Acupuncture Therapy on MCI Patients Using Functional Near-Infrared Spectroscopy

Effects of HD‐tDCS on Resting‐State Functional Connectivity in the Prefrontal Cortex: An fNIRS Study

Optimal Consensus Control for Heterogeneous Nonlinear Multiagent Systems with Partially Unknown Dynamics

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