Statistical Properties and Predictability of Extreme Epileptic Events

The use of extreme events theory for the analysis of spontaneous epileptic brain activity is a relevant multidisciplinary problem. It allows deeper understanding of pathological brain functioning and unraveling mechanisms underlying the epileptic seizure emergence along with its predictability. The latter is a desired goal in epileptology which might open the way for new therapies to control and prevent epileptic attacks. With this goal in mind, we applied the extreme event theory for studying statistical properties of electroencephalographic (EEG) recordings of WAG/Rij rats with genetic predisposition to absence epilepsy. Our approach allowed us to reveal extreme events inherent in this pathological spiking activity, highly pronounced in a particular frequency range. The return interval analysis showed that the epileptic seizures exhibit a highly-structural behavior during the active phase of the spiking activity. Obtained results evidenced a possibility for early (up to 7 s) prediction of epileptic seizures based on consideration of EEG statistical properties

ГОСПИТАЛЬНЫЕ РЕЗУЛЬТАТЫ БИМАММАРНОГО КОРОНАРНОГО ШУНТИРОВАНИЯ

HighlightsThe present study was conducted to evaluate in-hospital outcomes of one of the most effective and simultaneously controversial surgical techniques for myocardial revascularization using two internal thoracic arteries (ITA).To this date, this is the most complete analysis that has been carried out at the Research Institute on the topic of studying bilateral internal thoracic artery grafting (BITA). The results obtained are of great importance for the subsequent evaluation of long-term results. AbstractAim. To analyze in-hospital outcomes of BITA.Methods. The study included 232 patients who were admitted to the Cardiac Surgery Department for coronary artery bypass grafting (CABG). All patients were divided into 2 groups depending on the use of either single or bilateral ITA conduits. Both groups included equal number of patients – 116. In-hospital outcomes were analyzed.Results. BITA and CABG with single ITA were proven to be comparable regarding myocardial infarction, stroke, the need for percutaneous coronary intervention, death, and composite endpoint. At the same time BITA patients significantly more often had longer hospital stay and required inotropic drugs.Conclusion. BITA is a safe procedure comparable to classic CABG in terms of in-hospital complications, but at the same time, this intervention is associated with longer hospital stay, and extended inotropic drugs use.Основные положенияНастоящее исследование проведено для оценки госпитальных результатов одной из самых эффективных и одновременно противоречивых хирургических технологий реваскуляризации миокарда с применением двух внутренних грудных артерий.Представленный анализ является наиболее крупным из когда-либо выполненных специалистами НИИ КПССЗ по изучению бимаммарного коронарного шунтирования. Также полученные данные имеют важное значение для последующей оценки отдаленных результатов. РезюмеЦель. Оценить госпитальные результаты бимаммарного коронарного шунтирования.Материалы и методы. Изучены данные 232 историй болезни пациентов, поступивших в кардиохирургическое отделение для проведения коронарного шунтирования. Все больные были разделены на две группы в зависимости от использования одной или двух внутренних грудных артерий. В первую и вторую группы вошло равное количество пациентов – по 116 (50%) в каждой. Оценены результаты госпитального послеоперационного периода.Результаты. Бимаммарное и аортокоронарное шунтирование с использованием одной внутренней грудной артерии сопоставимы по таким госпитальным осложнениям, как инфаркт миокарда, инсульт, необходимость в чрескожном коронарном вмешательстве, а также по комбинированной конечной точке. Вместе с тем пациенты, перенесшие бимаммарное шунтирование, достоверно чаще нуждались в приеме инотропных препаратов, а также дольше находились в стационаре.Заключение. Бимаммарное шунтирование – безопасная процедура, сравнимая по госпитальным осложнениям с классическим аортокоронарным шунтированием, вместе с тем такое вмешательство требует более продолжительного пребывания пациентов в стационаре, а также дополнительного использования инотропных препаратов. 

БИМАММАРНОЕ КОРОНАРНОЕ ШУНТИРОВАНИЕ: ПЯТНАДЦАТИЛЕТНИЙ ОПЫТ

HighlightsBilateral internal thoracic artery (BITA) grafting is one of the most effective methods of direct myocardial revascularization. However, its results are still contradictory, despite the worldwide trend to use more autogenous arterial conduits.This study involves more than fifteen years of data in the use of BITA in Kuzbass in coronary artery disease surgery. The findings presented in the course of the analysis confirm the need to use both internal mammary arteries more actively. Aim. To analyze long-term results of BITA grafting in terms of more than 15 years follow-up.Methods. The study included 232 patients who were admitted at the Cardiac Surgery Department for coronary artery bypass grafting (CABG). All patients were divided into 2 groups depending on usage of single or bilateral internal thoracic artery conduits. Both groups included an equal number of patients 116 (50%). Long-term results were assessed in terms of more than 15 years follow-up.Results. BITA grafting is comparable with CABG in such major adverse cardiac and cerebrovascular events as repeated myocardial revascularization, stroke, and in combined endpoint such as myocardial infarction (MI), stroke, repeated myocardial revascularization, or patient’s death within 15 years. However, the BITA group is superior to the CABG group in freedom from MI, all-cause deaths, showing a higher life expectancy after surgery (p = 0.011), and improved left ventricular ejection fraction and decreased functional class of angina. Moreover, in the present research it was confirmed that the severity of atherosclerosis in the coronary arteries is lower after bypassing with autogenous arterial conduits.Conclusion. BITA is safe procedure comparable with CABG, however, it has more advantageous long-term clinical and angiographic results.Основные положенияБимаммарное коронарное шунтирование представляет собой один из эффективных методов прямой реваскуляризации миокарда. Однако до сих пор результаты процедуры противоречивы, несмотря на мировую тенденцию применять большее количество аутоартериальных кондуитов.Настоящее исследование отражает более чем пятнадцатилетние результаты использования этого метода в хирургическом лечении ишемической болезни сердца. Выводы, полученные в ходе анализа, подтверждают необходимость активнее применять обе внутренние грудные артерии. Цель. Оценить результаты бимаммарного коронарного шунтирования (БиМКШ) по данным более чем 15-летнего наблюдения.Материалы и методы. Обследованы 232 пациента, поступившие в кардиохирургическое отделение для проведения коронарного шунтирования (КШ). Все пациенты разделены на две группы в зависимости от использования одной или двух внутренних грудных артерий. В первую и вторую группы вошло равное количество больных – по 116 (50%) в каждой. Оценены результаты отдаленного (более 15 лет) послеоперационного периода.Результаты. БиМКШ сопоставимо со стандартным КШ по таким серьезным неблагоприятным сердечно-сосудистым событиям, как повторная реваскуляризация миокарда, инсульт, а также по комбинированной конечной точке, представленной инфарктом миокарда, инсультом, повторной реваскуляризацией миокарда, смертью пациента или их сочетанием. Вместе с тем БиМКШ превосходит стандартное КШ в свободе от инфаркта миокарда, случаях смерти от любых причин, демонстрируя более высокую продолжительность жизни больных после операции (p = 0,011), а также улучшает фракцию выброса левого желудочка и снижает функциональный класс стенокардии напряжения. Кроме этого, в настоящем исследовании установлено, что выраженность атеросклероза в коронарных артериях ниже после шунтирования аутоартериальными кондуитами, что, вероятно, связано с их коронаропротективным действием.Заключение. БиМКШ является безопасной процедурой, сравнимой с классическим КШ, однако демонстрирует более благоприятные отдаленные клинические и ангиографические результаты

Increasing Human Performance by Sharing Cognitive Load Using Brain-to-Brain Interface

Brain-computer interfaces (BCIs) attract a lot of attention because of their ability to improve the brain's efficiency in performing complex tasks using a computer. Furthermore, BCIs can increase human's performance not only due to human-machine interactions, but also thanks to an optimal distribution of cognitive load among all members of a group working on a common task, i.e., due to human-human interaction. The latter is of particular importance when sustained attention and alertness are required. In every day practice, this is a common occurrence, for example, among office workers, pilots of a military or a civil aircraft, power plant operators, etc. Their routinely work includes continuous monitoring of instrument readings and implies a heavy cognitive load due to processing large amounts of visual information. In this paper, we propose a brain-to-brain interface (BBI) which estimates brain states of every participant and distributes a cognitive load among all members of the group accomplishing together a common task. The BBI allows sharing the whole workload between all participants depending on their current cognitive performance estimated from their electrical brain activity. We show that the team efficiency can be increased due to redistribution of the work between participants so that the most difficult workload falls on the operator who exhibits maximum performance. Finally, we demonstrate that the human-to-human interaction is more efficient in the presence of a certain delay determined by brain rhythms. The obtained results are promising for the development of a new generation of communication systems based on neurophysiological brain activity of interacting people. Such BBIs will distribute a common task between all group members according to their individual physical conditions

Search for gravitational-lensing signatures in the full third observing run of the LIGO-Virgo network

Gravitational lensing by massive objects along the line of sight to the source causes distortions of gravitational wave-signals; such distortions may reveal information about fundamental physics, cosmology and astrophysics. In this work, we have extended the search for lensing signatures to all binary black hole events from the third observing run of the LIGO--Virgo network. We search for repeated signals from strong lensing by 1) performing targeted searches for subthreshold signals, 2) calculating the degree of overlap amongst the intrinsic parameters and sky location of pairs of signals, 3) comparing the similarities of the spectrograms amongst pairs of signals, and 4) performing dual-signal Bayesian analysis that takes into account selection effects and astrophysical knowledge. We also search for distortions to the gravitational waveform caused by 1) frequency-independent phase shifts in strongly lensed images, and 2) frequency-dependent modulation of the amplitude and phase due to point masses. None of these searches yields significant evidence for lensing. Finally, we use the non-detection of gravitational-wave lensing to constrain the lensing rate based on the latest merger-rate estimates and the fraction of dark matter composed of compact objects

Search for eccentric black hole coalescences during the third observing run of LIGO and Virgo

Despite the growing number of confident binary black hole coalescences observed through gravitational waves so far, the astrophysical origin of these binaries remains uncertain. Orbital eccentricity is one of the clearest tracers of binary formation channels. Identifying binary eccentricity, however, remains challenging due to the limited availability of gravitational waveforms that include effects of eccentricity. Here, we present observational results for a waveform-independent search sensitive to eccentric black hole coalescences, covering the third observing run (O3) of the LIGO and Virgo detectors. We identified no new high-significance candidates beyond those that were already identified with searches focusing on quasi-circular binaries. We determine the sensitivity of our search to high-mass (total mass M>70 M⊙) binaries covering eccentricities up to 0.3 at 15 Hz orbital frequency, and use this to compare model predictions to search results. Assuming all detections are indeed quasi-circular, for our fiducial population model, we place an upper limit for the merger rate density of high-mass binaries with eccentricities 0<e≤0.3 at 0.33 Gpc−3 yr−1 at 90\% confidence level

Ultralight vector dark matter search using data from the KAGRA O3GK run

Among the various candidates for dark matter (DM), ultralight vector DM can be probed by laser interferometric gravitational wave detectors through the measurement of oscillating length changes in the arm cavities. In this context, KAGRA has a unique feature due to differing compositions of its mirrors, enhancing the signal of vector DM in the length change in the auxiliary channels. Here we present the result of a search for U(1)B−L gauge boson DM using the KAGRA data from auxiliary length channels during the first joint observation run together with GEO600. By applying our search pipeline, which takes into account the stochastic nature of ultralight DM, upper bounds on the coupling strength between the U(1)B−L gauge boson and ordinary matter are obtained for a range of DM masses. While our constraints are less stringent than those derived from previous experiments, this study demonstrates the applicability of our method to the lower-mass vector DM search, which is made difficult in this measurement by the short observation time compared to the auto-correlation time scale of DM

Age-Related Changes in Functional Connectivity during the Sensorimotor Integration Detected by Artificial Neural Network

Large-scale functional connectivity is an important indicator of the brain’s normal functioning. The abnormalities in the connectivity pattern can be used as a diagnostic tool to detect various neurological disorders. The present paper describes the functional connectivity assessment based on artificial intelligence to reveal age-related changes in neural response in a simple motor execution task. Twenty subjects of two age groups performed repetitive motor tasks on command, while the whole-scalp EEG was recorded. We applied the model based on the feed-forward multilayer perceptron to detect functional relationships between five groups of sensors located over the frontal, parietal, left, right, and middle motor cortex. Functional dependence was evaluated with the predicted and original time series coefficient of determination. Then, we applied statistical analysis to highlight the significant features of the functional connectivity network assessed by our model. Our findings revealed the connectivity pattern is consistent with modern ideas of the healthy aging effect on neural activation. Elderly adults demonstrate a pronounced activation of the whole-brain theta-band network and decreased activation of frontal–parietal and motor areas of the mu-band. Between-subject analysis revealed a strengthening of inter-areal task-relevant links in elderly adults. These findings can be interpreted as an increased cognitive demand in elderly adults to perform simple motor tasks with the dominant hand, induced by age-related working memory decline

Dynamics of functional connectivity in multilayer cortical brain network during sensory information processing

Topology of a functional brain multilayer network is dynamically adjusted to provide optimal performance during accomplishing cognitive tasks, including sensory information processing. Functional connectivity between brain regions is achieved in terms of correlation or synchronization inference in recorded signals of neuronal activity. The promising approach for studying cortical network structure implies considering functional interactions in different frequency bands on the different layers of multilayer network model. Links between these layers can be restored based on cross-frequency couplings. While the topology of functional connectivity within each layer can be effectively restored from registered neurophysiological signals, mechanisms underlying coupling between different layers remain poorly understood. Here we consider evolution of the cortical network topology in alpha and beta frequency bands during visual stimuli processing. For each frequency band the functional connectivity between different brain regions is estimated by comparing Fourier spectra of EEG signals. The obtained functional topologies are considered as the layers of two-layer network. In the framework of a multilayer model we analyze evolution of functional network topology on both layers and reveal features of intralayer interaction underlying visual information processing in the brain