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"granger", "seizure"

Rong Li, Chongyu Hu, Liangcheng Wang, Ding Liu, Dingyang Liu, Wei Liao, Bo Xiao, Huafu Chen, Li Feng
Growing evidence has demonstrated widespread brain network alterations in temporal lobe epilepsy (TLE). However, the relatively accurate portrait of the subcortical-cortical relationship for impaired consciousness in TLE remains unclear. We proposed that consciousness-impairing seizures may invade subcortical arousal system and corresponding cortical regions, resulting in functional abnormalities and information flow disturbances between subcortical and cortical networks. We performed resting-state fMRI in 26 patients with TLE and 30 matched healthy controls...
January 7, 2019: Brain Imaging and Behavior
Chunfeng Yang, Wentao Xiang, Jiasong Wu, Youyong Kong, Longyu Jiang, Jèannes Régine Le Bouquin, Huazhong Shu
The objective is to deal with brain effective connectivity among epilepsy electroencephalogram (EEG) signals recorded by use of depth electrodes in the cerebral cortex of patients suffering from refractory epilepsy during their epileptic seizures. The Wiener-Granger Causality Index (WGCI) is a well-known effective measure that can be useful to detect causal relations of interdependence in these kinds of EEG signals. It is based on the linear autoregressive model, and the issue of the estimation of the model parameters plays an important role in the calculation accuracy and robustness of WGCI to do research on brain effective connectivity...
May 1, 2018: Sheng Wu Yi Xue Gong Cheng Xue za Zhi, Journal of Biomedical Engineering, Shengwu Yixue Gongchengxue Zazhi
Lu-Wei Jiang, Ruo-Bing Qian, Xian-Ming Fu, Dong Zhang, Nan Peng, Chao-Shi Niu, Ye-Han Wang
PURPOSE: Epilepsy is considered a disorder of neural networks. Patients diagnosed with refractory epilepsy frequently experience attention impairments. Seizure activity in epilepsy may disturb brain networks and damage the brain function of attention. The aims of this study were to assess functional and causal connectivities of the attention networks and default mode network using resting-state functional magnetic resonance imaging (fMRI). METHOD: Resting-state fMRI data were gathered from 19 patients with refractory epilepsy (mixed localization and aetiologies) and 21 healthy people...
November 2018: Epilepsy & Behavior: E&B
Nicoleta Stoicea, Kenneth Moran, Abdel-Rasoul Mahmoud, Andrew Glassman, Thomas Ellis, John Ryan, Jeffrey Granger, Nicholas Joseph, Nathan Salon, Wiebke Ackermann, Barbara Rogers, Weston Niermeyer, Sergio D Bergese
BACKGROUND: Tranexamic acid (TXA) is an antifibrinolytic agent that has shown promise in reducing blood loss during total hip arthroplasty (THA). Several studies have reported side effects of high-dose TXA administration, including myocardial infarction (MI), thromboembolic events, and seizures. These possible side effects have prevented the widespread adoption of TXA in the surgical community. METHODS: We conducted a retrospective chart review of 564 primary and revision THAs performed at a single academic center...
May 2018: Medicine (Baltimore)
Pieter van Mierlo, Octavian Lie, Willeke Staljanssens, Ana Coito, Serge Vulliémoz
We investigated the influence of processing steps in the estimation of multivariate directed functional connectivity during seizures recorded with intracranial EEG (iEEG) on seizure-onset zone (SOZ) localization. We studied the effect of (i) the number of nodes, (ii) time-series normalization, (iii) the choice of multivariate time-varying connectivity measure: Adaptive Directed Transfer Function (ADTF) or Adaptive Partial Directed Coherence (APDC) and (iv) graph theory measure: outdegree or shortest path length...
September 2018: Brain Topography
Tatiana M Medvedeva, Marina V Sysoeva, Gilles van Luijtelaar, Ilya V Sysoev
PURPOSE: The organization of neural networks and the mechanisms, which generate the highly stereotypical for absence epilepsy spike-wave discharges (SWDs) is heavily debated. Here we describe such a model which can both reproduce the characteristics of SWDs and dynamics of coupling between brain regions, relying mainly on properties of hierarchically organized networks of a large number of neuronal oscillators. MODEL: We used a two level mesoscale model. The first level consists of three structures: the nervus trigeminus serving as an input, the thalamus and the somatosensory cortex; the second level of a group of nearby situated neurons belonging to one of three modeled structures...
February 2018: Neural Networks: the Official Journal of the International Neural Network Society
Caiyun Wu, Jing Xiang, Jintao Sun, Shuyang Huang, Lu Tang, Ailiang Miao, Yuchen Zhou, Qiqi Chen, Zheng Hu, Xiaoshan Wang
OBJECTIVE: The cortico-thalamo-cortical network plays a key role in childhood absence epilepsy (CAE). However, the exact interaction between the cortex and the thalamus remains incompletely understood. This study aimed to investigate the dynamic changes of frequency-dependent neural networks during the initialization of absence seizures. METHODS: Magnetoencephalography data from 14 patients with CAE were recorded during and between seizures at a sampling rate of 6000Hz and analyzed in seven frequency bands...
August 15, 2017: Neuroscience
Eun-Hyoung Park, Joseph R Madsen
BACKGROUND: A critical conceptual step in epilepsy surgery is to locate the causal region of seizures. In practice, the causal region may be inferred from the set of electrodes showing early ictal activity. There would be advantages in deriving information about causal regions from interictal data as well. We applied Granger's statistical approach to baseline interictal data to calculate causal interactions. We hypothesized that maps of the Granger causality network (or GC maps) from interictal data might inform about the seizure network, and set out to see if "causality" in the Granger sense correlated with surgical targets...
January 1, 2018: Neurosurgery
Sora Ahn, Sumin Jo, Sang Beom Jun, Hyang Woon Lee, Seungjun Lee
In this paper, we studied the mechanisms underlying the suppression of seizure-like events (SLEs) by electrical stimulation. We conducted an in-vitro experiment using entorhinal cortex combined hippocampal slices and two convulsant drugs, bicuculline and 4-aminopyridine, to induce spontaneous SLEs. We used a microelectrode array to observe network dynamics over the entire hippocampal area simultaneously, including regions far from the stimulation site. We stimulated the entorhinal cortex region, which has been determined to be a focus of SLEs by Granger causality analysis of multichannel time series data, by an external electrode...
June 14, 2017: Neuroreport
Christos Koutlis, Dimitris Kugiumtzis
Measures of Granger causality on multivariate time series have been used to form the so-called causality networks. A causality network represents the interdependence structure of the underlying dynamical system or coupled dynamical systems, and its properties are quantified by network indices. In this work, it is investigated whether network indices on networks generated by an appropriate Granger causality measure can discriminate different coupling structures. The information based Granger causality measure of partial mutual information from mixed embedding (PMIME) is used to form causality networks, and a large number of network indices are ranked according to their ability to discriminate the different coupling structures...
September 2016: Chaos
F Vallone, E Vannini, A Cintio, M Caleo, A Di Garbo
Epilepsy is characterized by substantial network rearrangements leading to spontaneous seizures and little is known on how an epileptogenic focus impacts on neural activity in the contralateral hemisphere. Here, we used a model of unilateral epilepsy induced by injection of the synaptic blocker tetanus neurotoxin (TeNT) in the mouse primary visual cortex (V1). Local field potential (LFP) signals were simultaneously recorded from both hemispheres of each mouse in acute phase (peak of toxin action) and chronic condition (completion of TeNT effects)...
September 2016: Physical Review. E
Marina V Sysoeva, Lyudmila V Vinogradova, Galina D Kuznetsova, Ilya V Sysoev, Clementina M van Rijn
PURPOSE: Spike-and-wave discharges (SWDs) recorded in the cortical EEGs of WAG/Rij rats are the hallmark for absence epilepsy in this model. Although this type of epilepsy was long regarded as a form of primary generalized epilepsy, it is now recognized that there is an initiation zone - the perioral region of the somatosensory cortex. However, networks involved in spreading the seizure are not yet fully known. Previously, the dynamics of coupling between different layers of the perioral cortical region and between these zones and different thalamic nuclei was studied in time windows around the SWDs, using nonlinear Granger causality...
November 2016: Epilepsy & Behavior: E&B
Huilin Wei, Jie An, Hui Shen, Ling-Li Zeng, Shijun Qiu, Dewen Hu
Idiopathic generalized epilepsy (IGE) patients with generalized tonic-clonic seizures (GTCS) suffer long-term cognitive impairments, and present a higher incidence of psychosocial and psychiatric disturbances than healthy people. It is possible that the cognitive dysfunctions and higher psychopathological risk in IGE-GTCS derive from disturbed causal relationship among core neurocognitive brain networks. To test this hypothesis, we examined the effective connectivity across the salience network (SN), default mode network (DMN), and central executive network (CEN) using resting-state functional magnetic resonance imaging (fMRI) data collected from 27 IGE-GTCS patients and 29 healthy controls...
2016: Frontiers in Human Neuroscience
Ana Clara Silveira Broggini, Ingrid Miranda Esteves, Rodrigo Neves Romcy-Pereira, João Pereira Leite, Richardson Naves Leão
The pathologically synchronized neuronal activity in temporal lobe epilepsy (TLE) can be triggered by network events that were once normal. Under normal conditions, hippocampus and medial prefrontal cortex (mPFC) work in synchrony during a variety of cognitive states. Abnormal changes in this circuit may aid to seizure onset and also help to explain the high association of TLE with mood disorders. We used a TLE rat model generated by perforant path (PP) stimulation to understand whether synchrony between dorsal hippocampal and mPFC networks is altered shortly before a seizure episode...
May 2016: Experimental Neurology
Ana Coito, Melanie Genetti, Francesca Pittau, Giannina R Iannotti, Aljoscha Thomschewski, Yvonne Höller, Eugen Trinka, Roland Wiest, Margitta Seeck, Christoph M Michel, Gijs Plomp, Serge Vulliemoz
OBJECTIVE: In patients with epilepsy, seizure relapse and behavioral impairments can be observed despite the absence of interictal epileptiform discharges (IEDs). Therefore, the characterization of pathologic networks when IEDs are not present could have an important clinical value. Using Granger-causal modeling, we investigated whether directed functional connectivity was altered in electroencephalography (EEG) epochs free of IED in left and right temporal lobe epilepsy (LTLE and RTLE) compared to healthy controls...
March 2016: Epilepsia
M V Sysoeva, A Lüttjohann, G van Luijtelaar, I V Sysoev
PURPOSE: Spike and wave discharges (SWDs), generated within cortico-thalamo-cortical networks, are the electroencephalographic biomarker of absence epilepsy. The current work aims to identify mechanisms of SWD initiation, maintenance and termination by the analyses of dynamics and directionality of mutual interactions between the neocortex and various functionally different thalamic nuclei. METHODS: Local-field potential recordings of 16 male Wistar Albino Glaxo from Rijswijk (WAG/Rij) rats, equipped with electrodes targeting layer 4-6 of the somatosensory cortex, rostral and caudal reticular thalamic nuclei (rRTN and cRTN), ventro-posteromedial (VPM), anterior (ATN) and posterior (PO) thalamic nuclei, were obtained...
February 9, 2016: Neuroscience
Wai-Yin Wan, Don Weatherburn, Grant Wardlaw, Vasilis Sarafidis, Grant Sara
BACKGROUND: Direct evidence of the effect of drug seizures on drug use and drug-related harm is fairly sparse. The aim of this study was to see whether seizures of heroin, cocaine and ATS predict the number of people arrested for use and possession of these drugs and the number overdosing on them. METHOD: We examined the effect of seizure frequency and seizure weight on arrests for drug use and possession and on the frequency of drug overdose with autoregressive distributed lag (ARDL) models...
January 2016: International Journal on Drug Policy
Robert Coben, Iman Mohammad-Rezazadeh
Epilepsy is a chronic neurological disorder characterized by repeated seizures or excessive electrical discharges in a group of brain cells. Prevalence rates include about 50 million people worldwide and 10% of all people have at least one seizure at one time in their lives. Connectivity models of epilepsy serve to provide a deeper understanding of the processes that control and regulate seizure activity. These models have received initial support and have included measures of EEG, MEG, and MRI connectivity...
2015: Frontiers in Human Neuroscience
A M Gregory, R Nenert, J B Allendorfer, R Martin, R K Kana, J P Szaflarski
Effective visual memory encoding, a function important for everyday functioning, relies on episodic and semantic memory processes. In patients with medial temporal lobe epilepsy (MTLE), memory deficits are common as the structures typically involved in seizure generation are also involved in acquisition, maintenance, and retrieval of episodic memories. In this study, we used group independent component analysis (GICA) combined with Granger causality analysis to investigate the neuronal networks involved in visual memory encoding during a complex fMRI scene-encoding task in patients with left MTLE (LMTLE; N=28) and in patients with right MTLE (RMTLE; N=18)...
May 2015: Epilepsy & Behavior: E&B
Charles M Epstein, Bhim M Adhikari, Robert Gross, Jon Willie, Mukesh Dhamala
OBJECTIVE: In recent decades intracranial EEG (iEEG) recordings using increasing numbers of electrodes, higher sampling rates, and a variety of visual and quantitative analyses have indicated the presence of widespread, high frequency ictal and preictal oscillations (HFOs) associated with regions of seizure onset. Seizure freedom has been correlated with removal of brain regions generating pathologic HFOs. However, quantitative analysis of preictal HFOs has seldom been applied to the clinical problem of planning the surgical resection...
December 2014: Epilepsia
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