Dynamic functional connectivity and graph theory metrics in a rat model of temporal lobe epilepsy reveal a preference for brain states with a lower functional connectivity, segregation and integration

Christiaen, Emma; Goossens, Marie-Gabrielle; Descamps, Benedicte; Larsen, Lars Emil; Boon, Paul; Raedt, Robrecht; Vanhove, Christian

doi:10.1016/j.nbd.2020.104808

Cited by 22 publications

(25 citation statements)

References 32 publications

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“…Instead of the hypersynchrony brain network pattern, other studies have reported a suppression of connectivity in epileptogenesis in the intraperitoneal KA (IPKA) rat model of TLE. 16,19 One possible reason for the differences could be the different routes of administration. The intrahippocampal KA model results in more focal brain lesions than the IPKA model and has a more acute response than the intraperitoneal injection model.…”

Section: Discussionmentioning

confidence: 99%

“…17 A recent study indicated that a dynamic mechanism is responsible for altered resting-state functional brain networks in epilepsy: a shift of global and local excitability that supports the combination of hyper-and hypoconnectivity in the epileptic brain. 18 Although animal studies have identified brain network abnormalities related to epilepsy, [15][16][17]19 our understanding of brain network changes in animals that do not develop epilepsy, or so-called "lesioned controls," is limited. Compared to the healthy brain, epileptogenic network formation is considered to be associated with a series of insult-related compensations, leading to a disease-related, maladaptive plasticity.…”

Section: Introductionmentioning

confidence: 99%

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Topographical reorganization of brain functional connectivity during an early period of epileptogenesis

Harris

et al. 2021

Epilepsia

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Objective: The current study aims to investigate functional brain network representations during the early period of epileptogenesis. Methods: Eighteen rats with the intrahippocampal kainate model of mesial temporal lobe epilepsy were used for this experiment. Functional magnetic resonance imaging (fMRI) measurements were made 1 week after status epilepticus, followed by 2-4-month electrophysiological and video monitoring. Animals were identified as having (1) developed epilepsy (E+, n = 9) or (2) not developed epilepsy (E−, n = 6).Nine additional animals served as controls. Graph theory analysis was performed on the fMRI data to quantify the functional brain networks in all animals prior to the development of epilepsy. Spectrum clustering with the network features was performed to estimate their predictability in epileptogenesis. Results: Our data indicated that E+ animals showed an overall increase in functional connectivity strength compared to E− and control animals. Global network features and small-worldness of E− rats were similar to controls, whereas E+ rats demonstrated increased small-worldness, including increased reorganization degree, clustering coefficient, and global efficiency, with reduced shortest pathlength. A notable classification of the combined brain network parameters was found in E+ and E− animals. For the local network parameters, the E− rats showed increased hubs in sensorimotor cortex, and decreased hubness in hippocampus. The E+ rats showed a 1232 | LI et aL.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Topographical reorganization of brain functional connectivity during an early period of epileptogenesis

Harris

et al. 2021

Epilepsia

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“…Parts were successively immersed in different concentrations of alcohol, double-distilled water to hydrate, stained in HE, dehydrated, and sealed. The prepared tissue sections were observed under an optical microscope and photographed using a microimaging system ( Christiaen et al, 2020 ).…”

Section: Methodsmentioning

confidence: 99%

Wogonin preventive impact on hippocampal neurodegeneration, inflammation and cognitive defects in temporal lobe epilepsy

Guo

Wang

et al. 2020

Saudi Journal of Biological Sciences

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Previous studies demonstrated that the pathophysiological changes after temporal lobe epilepsy (TLE) such as oxidative stress, inflammatory reaction contribute to cognitive defect and neuronal damage. The present study was conducted to evaluate the anticonvulsant effect of wogonin ameliorates kainate-induced TLE, and to investigate the mechanism underlying these effects. Rats were divided into control, wogonin, kainate, and wogonin-pretreated kainate groups. The rat model of TLE was induced by unilateral intrahippocampal injection of 0.4 ug/ul of kainate. The results showed that the cognitive function in TLE rats was significantly impaired, and wogonin treatment improved cognitive function in the Morris water maze (MWM). H & E staining and TUNEL staining showed obvious damage in the hippocampus of TLE rats, and wogonin alleviated the damage. To evaluate the oxidative stress, the expression of MDA and GSH in plasma were detected. Nrf-2 and HO-1 mRNA expression in the hippocampus were detected. The levels of MDA in plasma increased in TLE rats, and the levels of GSH in plasma and Nrf-2, HO-1 in the brain decreased. Treatment with wogonin alleviated these changes. We also detected the mRNA expression of inflammatory mediators like IL-1β, TNF-α, and NF kB in the brain. The inflammatory reaction was significantly activated in the brain of TLE rats, and wogonin alleviated neuroinflammation. We detected the mRNA expression of Bcl-2, Bax, caspase-3, in the hippocampus. The levels of Bcl-2 decreased in TLE rats, Bax and caspase-3 increased, while wogonin alleviated these changes. The present study indicated that wogonin exerted a noticeable neuroprotective effect in kainate-induced TLE rats.

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“…2) Dynamic FC: To capture the dynamic FC, we performed the SWC method [22], [34]. Based on previous studies [35], [36], we selected a fixed window size of 30 s to provide a good trade-off between the false fluctuation and over-smoothing. With a step size of 1 s, we captured the channel-pairwise correlation, producing (channels × channels × sliding time) dynamic FC matrices for each subject, where sliding time is the difference between total signal times and window size.…”

Section: B Proposed Methodsmentioning

confidence: 99%

Detection of Emotional Sensitivity Using fNIRS Based Dynamic Functional Connectivity

Tang

Chong

Kiguchi

et al. 2021

IEEE Trans. Neural Syst. Rehabil. Eng.

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In this study, we proposed an analytical framework to identify dynamic task-based functional connectivity (FC) features as new biomarkers of emotional sensitivity in nursing students, by using a combination of unsupervised and supervised machine learning techniques. The dynamic FC was measured by functional Near-Infrared Spectroscopy (fNIRS), and computed using a sliding window correlation (SWC) analysis. A k-means clustering technique was applied to derive four recurring connectivity states. The states were characterized by both graph theory and semi-metric analysis. Occurrence probability and state transition were extracted as dynamic FC network features, and a Random Forest (RF) classifier was implemented to detect emotional sensitivity. The proposed method was trialled on 39 nursing students and 19 registered nurses during decisionmaking, where we assumed registered nurses have developed strategies to cope with emotional sensitivity. Emotional stimuli were selected from International Affective Digitized Sound System (IADS) database. Experiment results showed that registered nurses demonstrated single dominant connectivity state of taskrelevance, while nursing students displayed in two states and had higher level of task-irrelevant state connectivity. The results also showed that students were more susceptive to emotional stimuli, and the derived dynamic FC features provided a stronger discriminating power than heart rate variability (accuracy of 81.65% vs 71.03%) as biomarkers of emotional sensitivity. This work forms the first study to demonstrate the stability of fNIRS based dynamic FC states as a biomarker. In conclusion, the results support that the state distribution of dynamic FC could help reveal the differentiating factors between the nursing students and registered nurses during decision making, and it is anticipated that the biomarkers might be used as indicators when developing professional training related to emotional sensitivity.

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Dynamic functional connectivity and graph theory metrics in a rat model of temporal lobe epilepsy reveal a preference for brain states with a lower functional connectivity, segregation and integration

Cited by 22 publications

References 32 publications

Topographical reorganization of brain functional connectivity during an early period of epileptogenesis

Topographical reorganization of brain functional connectivity during an early period of epileptogenesis

Wogonin preventive impact on hippocampal neurodegeneration, inflammation and cognitive defects in temporal lobe epilepsy

Detection of Emotional Sensitivity Using fNIRS Based Dynamic Functional Connectivity

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