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

In drug-resistant focal epilepsy, planning surgical resection can involve presurgical intracranial EEG (iEEG) recordings to detect seizures and other iEEG patterns to improve postsurgical seizure outcome. We hypothesized that resection of tissue generating interictal high-frequency oscillations (HFOs, 80-500 Hz) in the iEEG predicts surgical outcome. In eight international epilepsy centres, iEEG was recorded during the presurgical evaluation of patients. The patients were of all ages, had epilepsy of all types, and underwent surgical resection of a single focus aiming at seizure freedom. In a prospective analysis, we applied a fully automated definition of HFO that was independent of the dataset. Using an observational cohort design that was blinded to postsurgical seizure outcome, we analysed HFO rates during non-rapid-eye-movement sleep. If channels had consistently high rates over multiple epochs, they were labelled the 'HFO area'. After HFO analysis, centres provided the electrode contacts located in the resected volume and the seizure outcome at follow-up ≥24 months after surgery. The study was registered at www.clinicaltrials.gov (NCT05332990). We received 160 iEEG datasets. In 146 datasets (91%), the HFO area could be defined. The patients with a completely resected HFO area were more likely to achieve seizure freedom in comparison to those without [odds ratio 2.61, 95% confidence interval (CI) 1.15-5.91, P = 0.02]. Among seizure-free patients, the HFO area was completely resected in 31 and not completely resected in 43. Among patients with recurrent seizures, the HFO area was completely resected in 14 and not completely resected in 58. When predicting seizure freedom, the negative predictive value of the HFO area (68%, CI 52-81) was higher than that for the resected volume as a predictor by itself (51%, CI 42-59, P = 4 × 10-5). The sensitivity and specificity for complete HFO area resection were 0.88 (CI 0.72-0.98) and 0.39 (CI 0.25-0.54), respectively, and the area under the curve was 0.83 (CI 0.58-0.97), indicating good predictive performance. In a blinded cohort study from independent epilepsy centres, applying a previously validated algorithm for HFO marking without the need for adjusting to new datasets allowed us to validate the clinical relevance of HFOs to plan the surgical resection.

• MeSH
• dítě MeSH
• dospělí MeSH
• elektroencefalografie metody   MeSH
• elektrokortikografie * metody   MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• prospektivní studie MeSH
• refrakterní epilepsie * chirurgie   patofyziologie   MeSH
• výsledek terapie MeSH
• záchvaty * chirurgie   patofyziologie   diagnóza   MeSH
• Check Tag
• dítě MeSH
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• multicentrická studie MeSH
• pozorovací studie MeSH

This study aimed to investigate the effects of performing either eccentric-only (ECC) or eccentric-concentric (ECC-CON) back squats (BS) with a supramaximal load on countermovement jump (CMJ) performance. Changes in front thigh skin surface temperature and mechanical properties (oscillation frequency and stiffness) of the vastus lateralis were also examined. Fourteen male powerlifters participated in this study (age: 22.5 ± 2.3 years, body weight: 84.2 ± 11.1 kg, height: 178 ± 7 cm, training experience: 5.4 ± 1.6 years, BS one-repetition maximum [1RM]: 177 ± 22.8 kg). The experimental sessions included 2 sets of 2 BS at 110% 1RM of either ECC-CON (load distributed by half on the barbell [55%] and on weight releasers [55%]) or ECC (only eccentric phase of BS) and CTRL with no CA applied. CMJ performance, mechanical properties, and skin surface temperature were measured before and at the third, sixth, ninth, and 12th min. After each protocol, only the ECC-CON condition led to a significant increase in CMJ height after individual optimal rest time compared to pre-CA (38.1 ± 5.2 vs. 39.8 ± 5.0 cm; p = 0.003; effect size [ES] = 0.32; Δ = 4.9 ± 5.0%) with a significant rise in skin surface temperature (32.98 ± 1.24 vs. 33.69 ± 0.96°C; p = 0.006; ES = 0.62; Δ = 2.2 ± 2.6%) and no significant changes in mechanical properties of the vastus lateralis. The ECC-CON condition led to a significant acute improvement in CMJ height and an increase in front thigh skin surface temperature among powerlifters. The ECC-CON supramaximal lower limb PAPE protocol should be effectively used among males representing high levels of lower limb muscle strength (>2 × body mass).

• MeSH
• biomechanika MeSH
• čtyřhlavý sval stehenní fyziologie   MeSH
• dospělí MeSH
• kosterní svaly fyziologie   MeSH
• lidé MeSH
• mladý dospělý MeSH
• odporový trénink MeSH
• sportovní výkon * fyziologie   MeSH
• stehno fyziologie   MeSH
• svalová síla fyziologie   MeSH
• teplota kůže * fyziologie   MeSH
• vzpírání * fyziologie   MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

BACKGROUND: Temporal interference stimulation (TIS) is a novel noninvasive electrical stimulation technique to focally modulate deep brain regions; a minimum of two high-frequency signals (f1 and f2 > 1 kHz) interfere to create an envelope-modulated signal at a deep brain target with the frequency of modulation equal to the difference frequency: Δf = |f2 - f1|. OBJECTIVE: The goals of this study were to verify the capability of TIS to modulate the subthalamic nucleus (STN) with Δf and to compare the effect of TIS and conventional deep brain stimulation (DBS) on the STN beta oscillations in patients with Parkinson's disease (PD). METHODS: DBS leads remained externalized after implantation, allowing local field potentials (LFPs) recordings in eight patients with PD. TIS was performed initially by two pairs (f1 = 9.00 kHz; f2 = 9.13 kHz, 4 mA peak-peak per pair maximum) of scalp electrodes placed in temporoparietal regions to focus the envelope signal maximum (Δf = 130 Hz) at the motor part of the STN target. RESULTS: The comparison between the baseline LFPs and recordings after TIS and conventional DBS sessions showed substantial suppression of high beta power peak after both types of stimulation in all patients. CONCLUSIONS: TIS has the potential to effectively modulate the STN and reduce the beta oscillatory activity in a completely noninvasive manner, as is traditionally possible only with intracranial DBS. Future studies should confirm the clinical effectiveness of TIS and determine whether TIS could be used to identify optimal DBS candidates and individualize DBS targets. © 2025 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

• MeSH
• beta rytmus EEG * fyziologie   MeSH
• hluboká mozková stimulace * metody   MeSH
• lidé středního věku MeSH
• lidé MeSH
• nucleus subthalamicus * patofyziologie   MeSH
• Parkinsonova nemoc * terapie   patofyziologie   MeSH
• senioři MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

The relationship between working memory (WM) and neuronal oscillations can be studied in detail using brain stimulation techniques, which provide a method for modulating these oscillations and thus influencing WM. The endogenous coupling between the amplitude of gamma oscillations and the phase of theta oscillations is crucial for cognitive control. Theta/gamma peak-coupled transcranial alternating current stimulation (TGCp-tACS) can modulate this coupling and thus influence WM performance. This study investigated the effects of TGCp-tACS on WM in older adults and compared their responses with those of younger participants from our previous work who underwent the same experimental design. Twenty-eight older subjects underwent both TGCp-tACS and sham stimulation sessions at least 72 h apart. Resting-state electroencephalography (EEG) was recorded before and after the interventions, and a WM task battery with five different WM tasks was performed during the interventions to assess various WM components. Outcomes measured included WM task performance (e.g., accuracy, reaction time (RT)) and changes in power spectral density (PSD) in different frequency bands. TGCp-tACS significantly decreased accuracy and RT on the 10- and 14-point Sternberg tasks and increased RT on the Digit Symbol Substitution Test in older adults. In contrast, younger participants showed a significant increase in accuracy only on the 14-item Sternberg task. Electrophysiological analysis revealed a decrease in delta and theta PSD and an increase in high gamma PSD in both younger and older participants after verum stimulation. In conclusion, theta-gamma coupling is essential for WM and modulation of this coupling affects WM performance. The effects of TGCp-tACS on WM vary with age due to natural brain changes. To better support older adults, the study suggests several strategies to improve cognitive function, including: Adjusting stimulation parameters, applying stimulation to two sites, conducting multiple sessions, and using brain imaging techniques for precise targeting.

• MeSH
• dospělí MeSH
• elektroencefalografie MeSH
• gama rytmus EEG * fyziologie   MeSH
• krátkodobá paměť * fyziologie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• přímá transkraniální stimulace mozku * MeSH
• reakční čas fyziologie   MeSH
• senioři MeSH
• stárnutí fyziologie   MeSH
• theta rytmus EEG * fyziologie   MeSH
• zdraví MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

Working memory (WM) is essential for the temporary storage and processing of information required for complex cognitive tasks and relies on neuronal theta and gamma oscillations. Given the limited capacity of WM, researchers have investigated various methods to improve it, including transcranial alternating current stimulation (tACS), which modulates brain activity at specific frequencies. One particularly promising approach is theta-gamma peak-coupled-tACS (TGCp-tACS), which simulates the natural interaction between theta and gamma oscillations that occurs during cognitive control in the brain. The aim of this study was to improve WM in healthy young adults with TGCp-tACS, focusing on both behavioral and neurophysiological outcomes. Thirty-one participants completed five WM tasks under both sham and verum stimulation conditions. Electroencephalography (EEG) recordings before and after stimulation showed that TGCp-tACS increased power spectral density (PSD) in the high-gamma region at the stimulation site, while PSD decreased in the theta and delta regions throughout the cortex. From a behavioral perspective, although no significant changes were observed in most tasks, there was a significant improvement in accuracy in the 14-item Sternberg task, indicating an improvement in phonological WM. In conclusion, TGCp-tACS has the potential to promote and improve the phonological component of WM. To fully realize the cognitive benefits, further research is needed to refine the stimulation parameters and account for individual differences, such as baseline cognitive status and hormonal factors.

• MeSH
• chování fyziologie   MeSH
• dospělí MeSH
• elektrická stimulace MeSH
• elektroencefalografie MeSH
• gama rytmus EEG fyziologie   MeSH
• krátkodobá paměť * fyziologie   MeSH
• lidé MeSH
• mladý dospělý MeSH
• přímá transkraniální stimulace mozku * metody   MeSH
• theta rytmus EEG fyziologie   MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

Antagonistic activity of brain networks likely plays a fundamental role in how the brain optimizes its performance by efficient allocation of computational resources. A prominent example involves externally/internally oriented attention tasks, implicating two anticorrelated, intrinsic brain networks: the default mode network (DMN) and the dorsal attention network (DAN). To elucidate electrophysiological underpinnings and causal interplay during attention switching, we recorded intracranial EEG (iEEG) from 25 epilepsy patients with electrode contacts localized in the DMN and DAN. We show antagonistic network dynamics of activation-related changes in high-frequency (> 50 Hz) and low-frequency (< 30 Hz) power. The temporal profile of information flow between the networks estimated by functional connectivity suggests that the activated network inhibits the other one, gating its activity by increasing the amplitude of the low-frequency oscillations. Insights about inter-network communication may have profound implications for various brain disorders in which these dynamics are compromised.

• MeSH
• dospělí MeSH
• elektroencefalografie MeSH
• elektrofyziologické jevy MeSH
• epilepsie patofyziologie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• mozek * fyziologie   patofyziologie   MeSH
• nervová síť * fyziologie   MeSH
• pozornost * fyziologie   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

Despite advances in understanding the cellular and molecular processes underlying memory and cognition, and recent successful modulation of cognitive performance in brain disorders, the neurophysiological mechanisms remain underexplored. High frequency oscillations beyond the classic electroencephalogram spectrum have emerged as a potential neural correlate of fundamental cognitive processes. High frequency oscillations are detected in the human mesial temporal lobe and neocortical intracranial recordings spanning gamma/epsilon (60-150 Hz), ripple (80-250 Hz) and higher frequency ranges. Separate from other non-oscillatory activities, these brief electrophysiological oscillations of distinct duration, frequency and amplitude are thought to be generated by coordinated spiking of neuronal ensembles within volumes as small as a single cortical column. Although the exact origins, mechanisms and physiological roles in health and disease remain elusive, they have been associated with human memory consolidation and cognitive processing. Recent studies suggest their involvement in encoding and recall of episodic memory with a possible role in the formation and reactivation of memory traces. High frequency oscillations are detected during encoding, throughout maintenance, and right before recall of remembered items, meeting a basic definition for an engram activity. The temporal coordination of high frequency oscillations reactivated across cortical and subcortical neural networks is ideally suited for integrating multimodal memory representations, which can be replayed and consolidated during states of wakefulness and sleep. High frequency oscillations have been shown to reflect coordinated bursts of neuronal assembly firing and offer a promising substrate for tracking and modulation of the hypothetical electrophysiological engram.

• MeSH
• elektroencefalografie MeSH
• kognice * fyziologie   MeSH
• lidé MeSH
• mozek fyziologie   MeSH
• mozkové vlny fyziologie   MeSH
• paměť fyziologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

Beta hypersynchrony was recently introduced into clinical practice in Parkinson's disease (PD) to identify the best stimulation contacts and for adaptive deep brain stimulation (aDBS) sensing. However, many other oscillopathies accompany the disease, and beta power sensing may not be optimal for all patients. The aim of this work was to study the potential clinical usefulness of beta power phase-amplitude coupling (PAC) with high frequency oscillations (HFOs). Subthalamic nucleus (STN) local field potentials (LFPs) from externalized DBS electrodes were recorded and analyzed in PD patients (n = 19). Beta power and HFOs were evaluated in a resting-state condition; PAC was then studied and compared with the electrode contact positions, structural connectivity, and medication state. Beta-HFO PAC (mainly in the 200-500 Hz range) was observed in all subjects. PAC was detectable more specifically in the motor part of the STN compared to beta power and HFOs. Moreover, the presence of PAC better corresponds to the stimulation setup based on the clinical effect. PAC is also sensitive to the laterality of symptoms and dopaminergic therapy, where the greater PAC cluster reflects the more affected side and medication "off" state. Coupling between beta power and HFOs is known to be a correlate of the PD "off" state. Beta-HFO PAC seems to be more sensitive than beta power itself and could be more helpful in the selection of the best clinical stimulation contact and probably also as a potential future input signal for aDBS.

• Publikační typ
• časopisecké články MeSH

BACKGROUND: Intraventricular hemorrhage (IVH) is an important cause of neurodevelopmental impairment in preterm infants. A number of risk factors for IVH have already been proposed; however, some controversies regarding optimal perinatal management persist. This study aimed to identify perinatal and neonatal attributes associated with IVH in a representative population of preterm infants. METHODS: Perinatal data on 1,279 very preterm infants (<32 weeks of gestation) admitted to a tertiary neonatal intensive care unit were analyzed. The records were assessed using univariate analysis and logistic regression model to evaluate the risk factors for any and high-grade IVH (grade III-IV according to the classification by Papile) within the first week after birth. RESULTS: The incidence of any IVH was 14.3% (183/1,279); the rate of low-grade (I-II) and high-grade (III-IV) IVH was 9.0% (115/1,279) and 5.3% (68/1,279), respectively. Univariate analysis revealed multiple factors significantly associated with intraventricular hemorrhage: lower gestational age and birth weight, absence of antenatal steroids, vaginal delivery, low Apgar score at 5 min, delivery room intubation, surfactant administration, high frequency oscillation, pulmonary hypertension, pulmonary hemorrhage, tension pneumothorax, persistent ductus arteriosus, hypotension and early onset sepsis. Logistic regression confirmed lower gestational age, vaginal delivery, ductus arteriosus and early onset sepsis to be independent predictors for any IVH. Pulmonary hemorrhage, tension pneumothorax and early onset sepsis were independent risk factors for high-grade IVH. Complete course of antenatal steroids was associated with a lower risk for any (odds ratio 0.58, 95% confidence interval 0.39-0.85; P = .006) and for high-grade intraventricular hemorrhage (odds ratio 0.36, 95% confidence interval 0.20-0.65; P < .001). CONCLUSION: The use of antenatal steroids and mode of delivery are crucial in the prevention of IVH; however, our study did not confirm the protective effect of placental transfusion. Severe respiratory insufficiency and circulatory instability remain to be powerful contributors to the development of IVH. Early detection and management of perinatal infection may also help to reduce the rate of brain injury and improve neurodevelopment in high-risk newborns.

• Publikační typ
• časopisecké články MeSH