Electrophysiological study
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OBJECTIVE: We comprehensively characterized a large pediatric cohort with focal cortical dysplasia (FCD) type 1 to expand the phenotypic spectrum and to identify predictors of postsurgical outcomes. METHODS: We included pediatric patients with histopathological diagnosis of isolated FCD type 1 and at least 1 year of postsurgical follow-up. We systematically reanalyzed clinical, electrophysiological, and radiological features. The results of this reanalysis served as independent variables for subsequent statistical analyses of outcome predictors. RESULTS: All children (N = 31) had drug-resistant epilepsy with varying impacts on neurodevelopment and cognition (presurgical intelligence quotient [IQ]/developmental quotient scores = 32-106). Low presurgical IQ was associated with abnormal slow background electroencephalographic (EEG) activity and disrupted sleep architecture. Scalp EEG showed predominantly multiregional and often bilateral epileptiform activity. Advanced epilepsy magnetic resonance imaging (MRI) protocols identified FCD-specific features in 74.2% of patients (23/31), 17 of whom were initially evaluated as MRI-negative. In six of eight MRI-negative cases, fluorodeoxyglucose-positron emission tomography (PET) and subtraction ictal single photon emission computed tomography coregistered to MRI helped localize the dysplastic cortex. Sixteen patients (51.6%) underwent invasive EEG. By the last follow-up (median = 5 years, interquartile range = 3.3-9 years), seizure freedom was achieved in 71% of patients (22/31), including seven of eight MRI-negative patients. Antiseizure medications were reduced in 21 patients, with complete withdrawal in six. Seizure outcome was predicted by a combination of the following descriptors: age at epilepsy onset, epilepsy duration, long-term invasive EEG, and specific MRI and PET findings. SIGNIFICANCE: This study highlights the broad phenotypic spectrum of FCD type 1, which spans far beyond the narrow descriptions of previous studies. The applied multilayered presurgical approach helped localize the epileptogenic zone in many previously nonlesional cases, resulting in improved postsurgical seizure outcomes, which are more favorable than previously reported for FCD type 1 patients.
- MeSH
- dítě MeSH
- elektroencefalografie * metody MeSH
- epilepsie MeSH
- fokální kortikální dysplazie MeSH
- kohortové studie MeSH
- kojenec MeSH
- lidé MeSH
- magnetická rezonanční tomografie * MeSH
- malformace mozkové kůry, skupina I * chirurgie komplikace diagnostické zobrazování MeSH
- malformace mozkové kůry chirurgie komplikace diagnostické zobrazování MeSH
- mladiství MeSH
- pozitronová emisní tomografie MeSH
- předškolní dítě MeSH
- refrakterní epilepsie * chirurgie diagnostické zobrazování patofyziologie MeSH
- výsledek terapie MeSH
- Check Tag
- dítě MeSH
- kojenec MeSH
- lidé MeSH
- mladiství MeSH
- mužské pohlaví MeSH
- předškolní dítě MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
N-Methyl-d-aspartate receptors (NMDARs) play a crucial role in excitatory neurotransmission, with numerous pathogenic variants identified in the GluN subunits, including their ligand-binding domains (LBDs). The prevailing hypothesis postulates that the endoplasmic reticulum (ER) quality control machinery verifies the agonist occupancy of NMDARs, but this was tested in a limited number of studies. Using microscopy and electrophysiology in the human embryonic kidney 293 (HEK293) cells, we found that surface expression of GluN1/GluN2A receptors containing a set of alanine substitutions within the LBDs correlated with the measured EC50 values for glycine (GluN1 subunit mutations) while not correlating with the measured EC50 values for l-glutamate (GluN2A subunit mutations). The mutant cycle of GluN1-S688 residue, including the pathogenic GluN1-S688Y and GluN1-S688P variants, showed a correlation between relative surface expression of the GluN1/GluN2A receptors and the measured EC50 values for glycine, as well as with the calculated ΔGbinding values for glycine obtained from molecular dynamics simulations. In contrast, the mutant cycle of GluN2A-S511 residue did not show any correlation between the relative surface expression of the GluN1/GluN2A receptors and the measured EC50 values for l-glutamate or calculated ΔGbinding values for l-glutamate. Coexpression of both mutated GluN1 and GluN2A subunits led to additive or synergistic alterations in the surface number of GluN1/GluN2A receptors. The synchronized ER release by ARIAD technology confirmed the altered early trafficking of GluN1/GluN2A receptors containing the mutated LBDs. The microscopical analysis from embryonal rat hippocampal neurons (both sexes) corroborated our conclusions from the HEK293 cells.
- MeSH
- glycin metabolismus MeSH
- HEK293 buňky MeSH
- hipokampus cytologie metabolismus MeSH
- krysa rodu rattus MeSH
- kyselina glutamová metabolismus MeSH
- lidé MeSH
- ligandy MeSH
- mutace genetika MeSH
- proteinové domény MeSH
- proteiny nervové tkáně MeSH
- receptory N-methyl-D-aspartátu * metabolismus genetika chemie MeSH
- transport proteinů fyziologie genetika MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
OBJECTIVE: The pre-surgical evaluation of epilepsy relies on the electrophysiological recordings of spontaneous seizures. During this period drug dose decreases increase the likelihood of seizures transitioning the brain from a low to high seizure likelihood state, so-called pro-ictal state. This study aimed to identify the dynamic brain changes characteristic of this transition from 386 ten-minute segments of intracranial EEG recordings of 29 patients with drug-refractory temporal lobe epilepsy. METHODS: We studied brain dynamics through mean phase locking value and relative power in gamma band, and autocorrelation function width. We further explored interactions with pro-ictal factors, such as rate of interictal spikes and high frequency oscillations, circadian and multi-day cycles, and clinical outcomes. RESULTS: We observed significant increases in gamma power in the epileptogenic zone, and critical slowing in both the epileptogenic zone and presumably healthy cortex. These changes were linked with increases in spike and high frequency oscillations rate. CONCLUSIONS: Brain dynamics changed on the slow time scale - from the beginning to the end of the multi-day interval - but did not change in the short-term during the pre-ictal interval, thus could reflect pro-ictal changes. SIGNIFICANCE: We highlight gamma power and critical slowing indices as markers of pro-ictal brain states, as well as their potential to track the seizure-related brain mechanisms during the presurgical evaluation of epilepsy patients.
- MeSH
- dospělí MeSH
- elektroencefalografie metody MeSH
- elektrokortikografie metody MeSH
- epilepsie temporálního laloku * patofyziologie diagnóza MeSH
- gama rytmus EEG * fyziologie MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladiství MeSH
- mladý dospělý MeSH
- mozek * patofyziologie MeSH
- refrakterní epilepsie * patofyziologie MeSH
- záchvaty * patofyziologie MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladiství MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
UNLABELLED: Schizophrenia is a complex disorder characterized by altered brain functional connectivity, detectable during both task and resting state conditions using different neuroimaging methods. To this day, electroencephalography (EEG) studies have reported inconsistent results, showing both hyper- and hypo-connectivity with diverse topographical distributions. Interpretation of these findings is complicated by volume-conduction effects, where local brain activity fluctuations project simultaneously to distant scalp regions (zero-phase lag), inducing spurious inter-electrode correlations. AIM: In the present study, we explored the network dynamics of schizophrenia using a novel functional connectivity metric-corrected imaginary phase locking value (ciPLV)-which is insensitive to changes in amplitude as well as interactions at zero-phase lag. This method, which is less prone to volume conduction effects, provides a more reliable estimate of sensor-space functional network connectivity in schizophrenia. METHODS: We employed a cross-sectional design, utilizing resting state EEG recordings from two adult groups: individuals diagnosed with chronic schizophrenia (n = 30) and a control group of healthy participants (n = 30), all aged between 18 and 55 years old. RESULTS: Our observations revealed that schizophrenia is characterized by a prevalence of excess theta (4-8 Hz) power localized to centroparietal electrodes. This was accompanied by significant alterations in inter- and intra-hemispheric functional network connectivity patterns, mainly between frontotemporal regions within the theta band and frontoparietal regions within beta/gamma bands. CONCLUSIONS: Our findings suggest that patients with schizophrenia demonstrate long-range electrophysiological connectivity abnormalities that are independent of spectral power (i.e., volume conduction). Overall, distinct hemispheric differences were present in frontotemporo-parietal networks in theta and beta/gamma bands. While preliminary, these alterations could be promising new candidate biomarkers of chronic schizophrenia.
- MeSH
- chronická nemoc MeSH
- dospělí MeSH
- elektroencefalografie * metody MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladiství MeSH
- mladý dospělý MeSH
- mozek patofyziologie diagnostické zobrazování MeSH
- nervová síť patofyziologie diagnostické zobrazování MeSH
- odpočinek fyziologie MeSH
- průřezové studie MeSH
- schizofrenie * patofyziologie diagnostické zobrazování MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladiství MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
Background and Objectives: Aortic stenosis (AS) is a frequent valvular disease characterized by the obstruction of left ventricular outflow. The resulting hemodynamic and structural changes create an arrhythmogenic substrate, with sudden cardiac death (SCD) often caused by ventricular arrhythmias (VAs) being a feared complication. This review examines the relationship between severe AS and VA, detailing the epidemiology, pathophysiological mechanisms, risk factors, and management approaches prior to aortic valve replacement (AVR). Materials and Methods: We conducted a comprehensive narrative review of the historical and contemporary literature investigating ventricular arrhythmias in severe aortic stenosis. Literature searches were performed in PubMed, MEDLINE, and Scopus databases using keywords, including "aortic stenosis", "ventricular arrhythmia", "sudden cardiac death", and "aortic valve replacement". Both landmark historical studies and modern investigations utilizing advanced monitoring techniques were included to provide a complete evolution of the understanding. Results: The prevalence of ventricular ectopy and non-sustained ventricular tachycardia increases with AS severity and symptom onset. Left ventricular hypertrophy, myocardial fibrosis, altered electrophysiological properties, and ischemia create the arrhythmogenic substrate. Risk factors include the male sex, concomitant aortic regurgitation, elevated filling pressures, and syncope. Diagnostic approaches range from standard electrocardiography to continuous monitoring and advanced imaging. Management centers on timely valve intervention, with medical therapy serving primarily as a bridge to AVR. Conclusions: Ventricular arrhythmias represent a consequence of valvular pathology in severe AS rather than an independent entity. Their presence signals advanced disease and a heightened risk for adverse outcomes. Multidisciplinary management with vigilant monitoring and prompt surgical referral is essential. Understanding this relationship enables clinicians to better identify high-risk patients requiring urgent intervention before life-threatening arrhythmic events occur.
- MeSH
- aortální stenóza * komplikace chirurgie patofyziologie MeSH
- chirurgická náhrada chlopně * metody MeSH
- komorová tachykardie etiologie MeSH
- lidé MeSH
- náhlá srdeční smrt etiologie MeSH
- rizikové faktory MeSH
- srdeční arytmie * etiologie patofyziologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
Epicardial access during electrophysiology procedures offers valuable insights and therapeutic options for managing ventricular arrhythmias (VAs). The current clinical consensus statement on epicardial VA ablation aims to provide clinicians with a comprehensive understanding of this complex clinical scenario. It offers structured advice and a systematic approach to patient management. Specific sections are devoted to anatomical considerations, criteria for epicardial access and mapping evaluation, methods of epicardial access, management of complications, training, and institutional requirements for epicardial VA ablation. This consensus is a joint effort of collaborating cardiac electrophysiology societies, including the European Heart Rhythm Association, the Heart Rhythm Society, the Asia Pacific Heart Rhythm Society, the Latin American Heart Rhythm Society, and the Canadian Heart Rhythm Society.
- MeSH
- elektrofyziologické techniky kardiologické normy MeSH
- epikardiální mapování MeSH
- katetrizační ablace * metody normy MeSH
- komorová tachykardie * chirurgie diagnóza patofyziologie MeSH
- konsensus * MeSH
- lidé MeSH
- perikard chirurgie MeSH
- srdeční arytmie chirurgie diagnóza patofyziologie terapie MeSH
- výsledek terapie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
- směrnice pro lékařskou praxi MeSH
Mutations in CACNA1C, the gene encoding Cav1.2 voltage-gated calcium channels, are associated with a spectrum of disorders, including Timothy syndrome and other neurodevelopmental and cardiac conditions. In this study, we report a child with a de novo heterozygous missense variant (c.1973T > C; L658P) in CACNA1C, presenting with refractory epilepsy, global developmental delay, hypotonia, and multiple systemic abnormalities, but without overt cardiac dysfunction. Electrophysiological analysis of the recombinant Cav1.2 L658P variant revealed profound gating alterations, most notably a significant hyperpolarizing shift in the voltage dependence of activation and inactivation. Additionally, molecular modeling suggested that the L658P mutation disrupts interactions within the IIS5 transmembrane segment, reducing the energy barrier for state transitions and facilitating channel opening at more negative voltages. These findings establish L658P as a pathogenic CACNA1C variant primarily associated with severe neurological dysfunction and expands the phenotypic spectrum of CACNA1C-related disorders.
- MeSH
- dítě MeSH
- gating iontového kanálu * MeSH
- lidé MeSH
- missense mutace genetika MeSH
- molekulární modely MeSH
- neurovývojové poruchy * genetika MeSH
- předškolní dítě MeSH
- sekvence aminokyselin MeSH
- vápníkové kanály - typ L * genetika MeSH
- Check Tag
- dítě MeSH
- lidé MeSH
- mužské pohlaví MeSH
- předškolní dítě MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- kazuistiky MeSH
Alzheimer's disease (AD), a leading cause of dementia worldwide, is a multifactorial neurodegenerative disorder characterized by amyloid-beta plaques, tauopathy, neuronal loss, neuro-inflammation, brain atrophy, and cognitive deficits. AD manifests as familial early-onset (FAD) with specific gene mutations or sporadic late-onset (LOAD) caused by various genetic and environmental factors. Numerous transgenic rodent models have been developed to understand AD pathology development and progression. The TgF344-AD rat model is a double transgenic model that carries two human gene mutations: APP with the Swedish mutation and PSEN-1 with delta exon 9 mutations. This model exhibits a complete repertoire of AD pathology in an age-dependent manner. This review summarizes multidisciplinary research insights gained from studying TgF344-AD rats in the context of AD pathology. We explore neuropathological findings; electrophysiological assessments revealing disrupted synaptic transmission, reduced spatial coding, network-level dysfunctions, and altered sleep architecture; behavioral studies highlighting impaired spatial memory; alterations in excitatory-inhibitory systems; and molecular and physiological changes in TgF344-AD rats emphasizing their age-related effects. Additionally, the impact of various interventions studied in the model is compiled, underscoring their role in bridging gaps in understanding AD pathogenesis. The TgF344-AD rat model offers significant potential in identifying biomarkers for early detection and therapeutic interventions, providing a robust platform for advancing translational AD research. Key words Alzheimer's disease, Transgenic AD models, TgF344-AD rats, Spatial coding.
- MeSH
- Alzheimerova nemoc * genetika patologie metabolismus MeSH
- amyloidový prekurzorový protein beta genetika metabolismus MeSH
- krysa rodu rattus MeSH
- lidé MeSH
- modely nemocí na zvířatech * MeSH
- mozek patologie metabolismus MeSH
- potkani inbrední F344 MeSH
- potkani transgenní * MeSH
- presenilin-1 genetika MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
Social withdrawal and deficits in social cognition are hallmarks of Alzheimer's disease (AD). While early deficits in social behavior and memory have been documented in mouse AD models, they remain understudied in rat models. Early-stage AD is accompanied by dysfunction of parvalbumin-positive (PV+) interneurons, implicating their potential connection to early symptoms. In this study, we employed a 5-trial social memory task to investigate early deficits in social cognition in 6-month-old TgF344-AD male and female rats. We counted the number of PV+ interneurons and recorded local field potentials during social interactions in the hippocampal CA2 - a region critical for social information processing. Our results show decreased social interest and novelty preference in TgF344-AD male and female rats. However, reduced PV+ interneuron numbers were observed only in female rats and specific to the CA2 area. The electrophysiological recordings revealed reduced theta-gamma phase-amplitude coupling in the CA2 during direct social interactions. We conclude that deficits in social cognition accompany early-stage AD in TgF344-AD rats and are potentially linked to PV+ interneuron and brain oscillatory dysfunction in the CA2 region of the hippocampus.
- MeSH
- Alzheimerova nemoc * patofyziologie patologie metabolismus MeSH
- hipokampální oblast CA2 * patofyziologie metabolismus patologie MeSH
- interneurony * metabolismus patologie MeSH
- krysa rodu rattus MeSH
- modely nemocí na zvířatech MeSH
- parvalbuminy * metabolismus MeSH
- pohlavní dimorfismus MeSH
- potkani inbrední F344 MeSH
- potkani transgenní MeSH
- sociální chování * MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
BACKGROUND: Diabetes mellitus (DM) causes myocardial electrical remodeling and promotes ventricular tachycardia and/or fibrillation (VT/VF). However, experimental studies have been frequently unsuccessful in developing a DM model with the expected high level of arrhythmic outcomes. The present study aims at evaluating cardiac electrophysiological properties in the rats with different Type 1 DM (T1DM) durations and identifying an electrophysiological phenotype associated with the high incidence of VT/VF. METHODS: The experiments were performed in 109 male Wistar rats (6-10 weeks old), subdivided into the groups of control, 4-weeks and 8-weeks T1DM (streptozotocin model). The animals were studied with epicardial electrophysiological mapping, whole-cell patch-clamp and histological examination. The VT/VF susceptibility was tested in ischemia/reperfusion induced in the anesthetized animals. RESULTS: In the 4-weeks T1DM group, we observed the increase in the incidence of reperfusion VT/VF, collagen deposition and dispersion of repolarization, slowed longitudinal and transverse conduction velocity, prolonged action potential duration, increased INa and ICaL currents, nonchanged Ito and IK1 currents. In the 8-weeks T1DM group, the VT/VF incidence, dispersion of repolarization, INa and Ito currents decreased. Other parameters persisted unchanged as compared to the 4-weeks T1DM group. CONCLUSIONS: Relatively early (4 weeks) diabetic electrical remodeling was proarrhythmic and included augmentation of sodium and calcium currents in the presence of fibrosis and slowed conduction and increased dispersion of repolarization. An unexpected finding was that diabetic arrhythmogenesis was associated with the increase in depolarizing transmembrane currents. Further research is warranted to elucidate molecular mechanisms and test the potential for the control of observed changes.
- MeSH
- diabetes mellitus 1. typu * komplikace patofyziologie MeSH
- experimentální diabetes mellitus patofyziologie komplikace MeSH
- fibrilace komor patofyziologie MeSH
- komorová tachykardie patofyziologie etiologie MeSH
- krysa rodu rattus MeSH
- modely nemocí na zvířatech MeSH
- potkani Wistar * MeSH
- remodelace komor MeSH
- srdeční arytmie patofyziologie etiologie MeSH
- srdeční komory patofyziologie MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH