bluuebunny/crossref_metadata_2025 huggingface dataset:
Mathematical Model of Human Capital Dynamics
Authors: Trusov N. V. , Shananin A. A.
Published: April 2024

A mathematical description of household economic behavior is studied. On the one hand, households are consumers that seek to maximize the discounted utility function in an imperfect market of savings and consumer loans. On the other hand, households are workers in the labor market; they receive a wage and seek to enhance their skills to receive a higher wage. An increase in the level of worker’s skill is achieved via investment in human capital. In this paper, a mathematical model of the worker’s behavior in the labor market is represented in the form of an infinite-horizon optimal control problem. A solution existence theorem is proved, and necessary optimality conditions are obtained in the form of Pontryagin’s maximum principle. The model is identified using Russian statistical data for various social layers.
On a Particular Solution of the σ-Commutation Problem () for Toeplitz and Hankel Matrices
Authors: Chugunov V. N. , Ikramov Kh. D.
Published: April 2024

A unified approach is proposed to the construction of matrix pairs (T,H) that solve the ‑commutation problem for Toeplitz and Hankel matrices. For a certain particular case, a family of solutions is derived.
AN APPROACH TO THE IMPLEMENTATION OF THE MULTIGRID METHOD WITH FULL APPROXIMATION FOR CFD PROBLEMS
Authors: Gorobets A. V.
Published: April 2024

This paper is devoted to the use of the multigrid method to accelerate calculations of compressible flows in a stationary formulation on unstructured grids. The multigrid method is used with the construction of a full approximation for each grid level (FAS MG—Full Approximation Scheme Multigrid). In the case of an unstructured grid, such a method can cause difficulties associated both with the construction of grid levels and transition operators between them, and with software implementation in the existing simulation code. The program needs to deal with several different discretizations at once. If the entire data structure, including arrays with grid data, topology, and time integration data, was designed to work on a single grid, then the implementation of the FAS MG can turn into a disaster involving rewriting the entire code. The purpose of this work is to achieve multiple acceleration of calculations at the cost of minimal effort. The problem of implementing the multigrid method on the basis of an existing software package that was not designed to work with several grid levels is solved. The implementation of the multigrid method in an MPI parallel code is carried out in such a way that there is no need to rewrite the program to work with multiple grids at all. Also, difficulties with constructing grid levels for an unstructured grid are avoided; agglomeration of cells is not used, and the number of faces per cell at coarse levels is not increased. In fact, this paper describes how to deploy a FAS MG accelerator in literally a week, even in code that is outdated from the point of view of software architecture.
Three-Level Schemes with Double Change in the Time Step
Authors: Vabishchevich P. N.
Published: April 2024

Nonstationary problems are solved numerically by applying multilevel (with more than two levels) time approximations. They are easy to construct and relatively easy to study in the case of uniform grids. However, the numerical study of application-oriented problems often involves approximations with a variable time step. The construction of multilevel schemes on nonuniform grids is associated with maintaining the prescribed accuracy and ensuring the stability of the approximate solution. In this paper, three-level schemes for the approximate solution of the Cauchy problem for a second-order evolution equation are constructed in the special case of a doubled or halved step size. The focus is on the approximation features in the transition between different step sizes. The study is based on general results of the stability (well-posedness) theory of operator-difference schemes in a finite-dimensional Hilbert space. Estimates for stability with respect to initial data and the right-hand side are obtained in the case of a doubled or halved time step.
Data Parallelization Algorithms for the Direct Simulation Monte Carlo Method for Rarefied Gas Flows on the Basis of OpenMP Technology
Authors: Bykov N. Yu. , Fyodorov S. A.
Published: April 2024

A data parallelization algorithm for the direct simulation Monte Carlo method for rarefied gas flows is considered. The scaling of performance of the main algorithm procedures are analyzed. Satisfactory performance scaling of the parallel particle indexing procedure is shown, and an algorithm for speeding up the operation of this procedure is proposed. Using examples of solving problems of free flow and flow around a cone for a 28-core node with shared memory, an acceptable speedup of the entire algorithm was obtained. The efficiency of the data parallelization algorithm and the computational domain decomposition algorithm for free flow is compared. Using the developed parallel code, a study of the supersonic rarefied flow around a cone is carried out.
Accelerating the Solution of the Boltzmann Equation by Controlling Contributions to the Collision Integral
Authors: Tcheremissine F. G.
Published: April 2024

A method of reducing the number of arithmetic operations needed to evaluate the Boltzmann collision integral by the conservative projection method is proposed. This is achieved by eliminating the contributions that are less than a certain threshold. An estimate of the maximum magnitude of this threshold is given. For four such thresholds that differ by an order of magnitude from each other, calculations of the flows of rarefied gas at Mach numbers in the range from 0.5 to 10 are carried out, and the results are compared with those obtained using the basic method. In all cases, there is a slight (within a few percent) difference for the highest threshold and almost complete coincidence for the other thresholds. A multiple acceleration of the solution of the Boltzmann equation was obtained, which is most significant for large Mach numbers.
Numerical and Theoretical Analysis of Model Equations for Multicomponent Rarefied Gas
Authors: Frolova A. A.
Published: April 2024

Model equations approximating the system of Boltzmann equations for a multicomponent gas are investigated. Methods for determining parameters in relaxation terms corresponding to cross-collision integrals are analyzed. Numerical solutions based on three model systems and the Boltzmann equations are compared as applied to the following problems: relaxation of a mixture to equilibrium, shock wave structure, and the dynamics of a vapor-gas cloud generated by pulsed laser irradiation of a target. It is shown that the parameters in the relaxation operators influence the degree of difference in the solutions produced by the various models.
A Uniformly Convergent Numerical Method for Singularly Perturbed Semilinear Integro-Differential Equations with Two Integral Boundary Conditions
Authors: Gunes B. , Cakir M.
Published: April 2024

This paper purposes to present a new discrete scheme for the singularly perturbed semilinear Volterra–Fredholm integro-differential equation including two integral boundary conditions. Initially, some analytical properties of the solution are given. Then, using the composite numerical integration formulas and implicit difference rules, the finite difference scheme is established on a uniform mesh. Error approximations for the approximate solution and stability bounds are investigated in the discrete maximum norm. Finally, a numerical example is solved to show -uniform convergence of the suggested difference scheme.
Nonclassical Heat Transfer in a Microchannel and a Problem for Lattice Boltzmann Equations
Authors: Ilyin O. V.
Published: April 2024

A one-dimensional problem of heat transfer in a bounded domain (microchannel) filled with rarefied gas is considered. Two molecular beams enter the domain from the left boundary, the velocities of the particles are equal in the each beam. The diffuse reflection condition is set on the right boundary. It is shown using the Shakhov kinetic model that by varying the ratio of velocities in the molecular beams it is possible to obtain a heat flux of various magnitudes and signs such that the te-mperatures on the left and right boundaries are equal or the temperature gradient in the boundary layer has the same sign as the heat flux. This problem is related to the problem of constructing lattice Boltzmann equations with four velocities, which can reproduce the first Maxwell half-moments. It is shown that in this case the optimal ratio of discrete velocities is 1 : 4.
Generalisation of the Penalised Wall Function Method for the Simulation of Turbulent flows With Unfavourable Pressure Gradients
Authors: Vasilyev O. V. , Zhdanova N. S.
Published: April 2024

The penalized wall function method for simulation of compressible near-wall turbulent flow regions in the numerical modeling of viscous compressible flows is developed. The method is formulated as a differential condition to match the outer and the wall function solutions and is based on a generalized characteristic-based volume penalization method to transfer shear stress from the outer region of the boundary layer to the wall. The method is modified to extend its applicability to turbulent flows with adverse pressure gradient, when separation and reattachment zones are formed, as well as to use computational meshes with coarser near-wall resolution. These advantages are demonstrated for two test problems, namely, the flow over a flat plate with zero and adverse pressure gradients.
EFFECT OF TAURINE ON MANIFESTATION OF AUDIOGENIC EPILEPSY IN RATS WITH PENDULUM MOVEMENTS
Authors: Alekhina T. A.
Published: April 2024

A decrease of taurine in hippocampus of the line of rats with pendulum movements (PM), predisposed to audiogenic epilepsy, was shown. Taurine (aminoethanesulfonic acid) is known to be an anticonvulsant drug. The aim of the present work was to verify the predictive validity of taurine in rats with pendulum movements (PM). In neonatal period the exogenous taurine administration did not influence a convulsive activity at the age of 1.5 and 3 months in PM rats. The increase in the number of audiogenic seizures after taurine injections was found in adolescent period in 1.5 months and in prolonged point – in 3 months. The number of abortive seizures decreased under acute injection of taurine in adult PM rats, but the level of ictal and postictal indicators restored one month later, at the age of 4 months. Obtained results indicate the absence of effect of taurine administered to rats in the neonatal age, while at the long-term scale, the rats showed the increasing seizure activity under the action of taurine in adolescent period and confirm the predictive validity of this drug in adult PM rats.
ASSOCIATION OF THE ZNF804A rs1344706 GENE POLYMORPHISM WITH THE INDUCED EEG RHYTHMS IN VISUAL PERCEPTION OF THE VERBAL STIMULI IN HEALTHY SUBJECTS AND IN SCHIZOPHRENIA
Authors: Garakh Zh. V. , Golimbet V. E. , Larionova E. V. , Lezheiko T. V. , Strelets V. B. , Zaytseva Yu.
Published: April 2024

We studied the relationship between the ZNF804A rs1344706 gene polymorphism and the parameters of event-related synchronization/desynchronization of EEG rhythms in visual perception of semantic and meaningless verbal information in patients with schizophrenia and schizophrenia spectrum disorders (n = 93) and mentally healthy subjects (n = 93). When reading verbal information regardless of psychiatric status, the theta rhythm synchronization was less pronounced in subjects with the AA genotype than in carriers of allele C. In healthy subjects, the carriers of the AA genotype, in comparison with carriers of allele C, the synchronization of theta rhythm in the posterior cortical areas of the left hemisphere was reduced, and there were no differences in the synchronization of gamma and desynchronization of mu rhythms when perceiving semantic and nonsensical verbal information. In patients with genotype AA, compared with carriers of allele C, the desynchronization of mu rhythm was smaller, which correlated with the severity of poverty of speech on the PANSS scale. The study results indicate a modulating effect of the rs1344706 polymorphism of the ZNF804A gene on the neurophysiological characteristics of the reading process and its contribution to the variability of clinically expressed language disorders.
WALKING OF A DECEREBRATE CAT AT SIMULTANEOUSLY DIFFERENT SPEEDS ON A SPLIT TREDBAN
Authors: Lyakhovetskii V. A. , Shkorbatova P. Y. , Gorskii O. V. , Musienko P. E. , Merkulyeva N.S.
Published: April 2024

The decisive role of sensory input in the initiation and modulation of locomotion has been shown repeatedly. One way to explore this input is the “split” treadmill paradigm. In the present study, a comparative analysis of the walking of a decerebrate cat on a split treadmill was carried out, the belts of which moved not only at different speeds (differed by 3 times), but also in different directions (forward and backward). The reciprocal work of two limbs, as well as the flexor and extensor muscles of each limb, is shown in such a locomotor mode. Two main walking strategies were identified: in response to one step of the limb walking along the slow treadmill belt, the limb walking along the fast belt made either one (1 : 1 mode) or two steps (1 : 2); strategies could interchange. The results of the study suggest the preservation of the integration of the locomotor networks of the two limbs with a significant mismatch of their sensory inputs.
THETA AND ALPHA BANDS SPECTRAL POWER OF RESTING-STATE EEG IN GROUPS WITH DIFFERENT EFFICIENCY OF JOINT ACTIVITY IN DIADS
Authors: Murtazina E. P. , Ginzburg-Shic Yu. A.
Published: April 2024

The aim of the study was to compare the spectral characteristics of theta and alpha frequency bands of the resting-state EEG between groups of subjects with different performance of subsequent joint sensorimotor activity in dyads. The study involved 26 men who, in 13 pairs, performed “Columns” trainings with biofeedback from EMG signals from the flexor muscles of the leading hand. According to their performance, the subjects of each pair were assigned to one of 2 groups: “winners” or “losers”. A higher spectral power of the theta rhythm of the EEG with closed eyes was found in the group of “losers” in comparison with the group of “winners” in the frontal, central and temporal zones of the cortex. The “winners” showed a higher level of spectral power of the EEG alpha rhythm with the eyes closed, especially in the alpha-2 frequency range in all 8 zones. The effectiveness of individual and joint training correlated negatively with the theta power and positively with the power of the EEG alpha rhythms in the closed-eyed state.
COHERENCE OF THE TETA1-BAND EEG IN A STATE OF RELATIVE REST AND DURING ATTENTION TESTING IN SUBJECTS WITH DIFFERENT LEVELS OF TRAIT ANXIETY
Authors: Dzhebrailova T. D. , Korobeinikova I. I. , Karatygin N. A. , Venerina Y. A. , Yantikova E. V.
Published: April 2024

Anxiety has a significant impact on the effectiveness of cognitive activity, which may be due to the peculiarities of the organization of voluntary and involuntary attention in individuals with different anxiety. Aim: to examine functional cortical connections in subjects with different levels of trait anxiety in a state of relative rest and when performing an attention test with usage of the coherent analysis of the teta1-band EEG (4–6 Hz). Coherence of teta1-band of EEG was analyzed in subjects (43 people, men aged 19–21 years) with low, medium and high level of trait anxiety (TA, according to C.D. Spielberger) in three experimental situations: the state of relative rest with closed eyes, the initial state before performing the test (with eyes opened) and during the test (red-black tables of F.D. Gorbov). Subjects with high TA in the state of relative rest with their eyes closed had a lower right-hemisphere coherence of the teta1-band EEG in the system of interrelations with focus in the temporal lead. In the initial state, with eyes opened and during test performing, individuals with high TA showed high level of interhemispheric coherence of the teta1-band of EEG. The highest lability of the structure of coherent relationships in the teta1-range of the EEG was observed in subjects with medium TA, who demonstrated an increase mainly in the interhemispheric coherence of most areas of the cortex during the test compared to the initial state. Individuals with high TA were characterized by relative inertia of the structure of coherent relationships in the teta1-range of the EEG at the stages of examination. The results of the study indicate that trait anxiety is one of the factors modulating the organization of neurocognitive networks both in a state of relative rest and during attention testing.
ACTIVITY OF THE MIRROR NEURON SYSTEM IN PEOPLE WITH DEPRESSIVE SYMPTOMS
Authors: Karimova E. D. , Smolskaya D. V. , Naratkina A. A.
Published: April 2024

The global events of the last few years have led to the fact that more and more people are beginning to experience depressive symptoms. Developing depression significantly affects the emotional state of a person and his perception of the world around him. The purpose of this study was to analyze the reactions of mu- and alpha-rhythms reflecting the work of the mirror and visual systems of the brain, when perceiving and repeating emotionally colored social stimuli in people with different levels of depression. The study involved 32 healthy subjects who were divided into two groups – with high and low levels of depression on the Beck scale. A 32-channel EEG was recorded in two experimental blocks activating the emotional and motor components of the mirror neuron system (MNS): 1) when perceiving emotional faces expressing joy or grief; 2) when observing and repeating motor hand gestures. The desynchronization levels of the mu- and alpha-rhythm components in each of the tasks identified by the independent component method (ICA) were analyzed. It was found that the mu- desynchronization was significantly higher in people with depression when repeating motor hand movements, as well as when perceiving negative emotional facial expressions. Desynchronization of the alpha rhythm did not differ in the two groups of volunteers. Thus, the development of a depressive state increases MNS activation, and its sensitivity to negative emotional stimuli. This effect does not apply to the visual cortex and visual attention.
METHODS OF BRAIN RESEARCH IN THE CERVICAL DYSTONIA
Authors: Ragimova A. , Feurra M.
Published: April 2024

The review is based on 149 foreign and Russian articles. The features of the brain functioning in cervical dystonia (CD) through the prism of modern technologies are reviewed. CD is hard to diagnose currently. CD is one of the promising areas not only in the clinical paradigm. In the future, CD can become an interesting model for studying the features of the balance of excitation/inhibition in brain neurons with the use of modern technologies. Using CD as a model of specific changes in function connections of brain regions, it would be possible to extrapolate the results to a healthy population and to the patients with other neurological or mental diseases.
UNNOTICED BUT NOT FORGOTTEN: EEG-CORRELATES OF AMBIGUOUS FIGURES PRIMING EFFECTS
Authors: Filippova M. G. , Chernov R. V. , Gorbunov I. A.
Published: April 2024

In order to find evidence of the inhibition or episodic retrieval account to explain the effect of negative priming, a study of behavioral and EEG-correlates of ambiguous figures perception, which are used as primes for the lexical decision task. It is shown that at the behavioral level the noticed meanings of used images demonstrate a positive, unnoticed – a negative priming-effect. EEG correlates of these effects in the anterio-central regions of the brain were revealed. Thus, the correlate of positive priming is attenuation of the N400 component, and the correlate of negative priming is attenuation of the late positive complex. Both components are considered in the literature as indicators of episodic retrieval, a memory-related process. The fact that the priming effect of the unnoticed meanings of ambiguous figures at the psychophysiological level is expressed in memory phenomena leads to the conclusion that the subjects remember the meanings they did not notice.
TIME COURSE AND VISUAL PRESENTATION EFFECTS ON THE MOTOR MIRROR NEURON SYSTEM INDUCED BY TRANSCRANIAL MAGNETIC STIMULATION
Authors: Nietto-Doval K. , Ragimova A. A. , Feurra M.
Published: April 2024

The study of mirror neurons (MN) has a long way since its discovery on monkeys and later on humans. However, there are inconsistencies on the way that stimuli are presented and on the time of stimuli presentation. Which is the optimal way to present motor movement stimuli? Is it possible to estimate the time course of the mirror neurons effect by using transcranial magnetic stimulation at specific time windows? In the current study we investigated different type of stimuli presentation (photo and video of hand movements) by using single pulse Transcranial Magnetic Stimulation of the dominant primary motor cortex (M1) at different time windows (0, 320, 640 ms). Motor evoked potentials from FDI (index finger muscle) and ADM (little finger muscle) were recorded on 11 healthy subjects at rest with their hands in orthogonal position while only observing the visual stimuli in three different presentation conditions. Our results showed that Video presentation induces the strongest mirror effect at 320 ms from the movement onset. This effect is muscle specific. The current evidence provides an optimal protocol for the investigation of the mirror neurons system in humans and pave the way for future clinical application and rehabilitation.
DYNAMICS OF THE PARIETAL-OCCIPITAL ALPHA RHYTHM ACTIVITY DURING COMPARISON OF VISUAL STIMULI DURATIONS
Authors: Rogachev A. O. , Sysoeva O. V.
Published: April 2024

This research is aimed at studying the dynamics of the parietal-occipital alpha rhythm in its connection with the process of stimuli duration comparison. EEG study was conducted in which participants (n = 48) were asked to compare pairs of visual stimuli of different durations ranging from 3.2 to 6.4 s. The time-frequency analysis of the EEG was carried out in the range of 8–12 Hz. The power of alpha rhythm increases from the stimulus onset to the middle of its presentation, but then its dynamic depends on the stimulus duration: it further increases for short durations (3.2, 3.6, 4.0 s), stays the same for middle durations (4.4, 4.8, 5.2 s) and decreases for long durations (5.6, 6.0, 6.4 s). The relative decrease of alpha power for long stimuli in relation to the short ones was related to subjective perception of time. The results are discussed from the point of view of the “dual klepsydra” model: it is assumed that alpha rhythm acts as an electrophysiological correlate of the functioning of “neural accumulators” associated with the subjective passage of time.
ANALYSIS OF BRAIN AND MUSCLE ACTIVITY DURING CONTROL OF BRAIN-SPINE NEUROINTERFACE
Authors: Bobrova E. V. , Reshetnikova V. V. , Grishin A. A. , Vershinina E. A. , Isaev M. R. , Plyachenko D. R. , Bobrov P. D. , Gerasimenko Yu. P.
Published: April 2024

A brain-spine neurointerface based on the kinesthetic imagination of foot dorsiflexion with additional activation of foot movement by Biokin robotic device (mechanotherapy), and transcutaneous electrical spinal cord stimulation (TESCS) has been developed. Accuracy of classification of EEG-signals during the neurointerface control was on average 68% and significantly increases with the addition of mechanotherapy and TESCS by 9%. The EMG activity of the tibialis anterior (TA) – the muscle, which performs dorsiflexion of the foot, significantly increased during the instruction to imagine movement compared to that during the instruction to be at rest. The addition of mechanotherapy and TESCS during the neurointerface control has a greater effect not on the increase in TA activity when imagining the movement of the ipsilateral foot, but on the decrease in TA activity at rest. The revealed effects are apparently important for the formation of adequate coordination patterns of control signals from the CNS and of muscle activity during the implementation of movements and can be used in the clinical rehabilitation of motor activity using the cortico-spinal neurointerface.
NEUROINFLAMMATION AND IMMUNE DYSFUNCTION IN THE PATHOGENESIS OF PARKINSON’S DISEASE
Authors: Idova G. V. , Alperina E. L. , Zhanaeva S. Ya.
Published: April 2024

Parkinson’s disease (PD) is a chronic progressive neurodegenerative disorder, characterized by dopaminergic neuronal loss, aggregation of alpha-synuclein and severe motor impairments. This review summarizes current data on the key role of neuroinflammation and immune dysfunction in neurodegeneration and disease development. We examine clinical and experimental evidence for microglia activation, participation of Toll-like receptors in this process, a wide range of chemokines and pro- and anti-inflammatory cytokines in the course of the disease. Emphasis is also made on the impact of the innate and adaptive immune responses in the mechanisms of systemic inflammation both in the brain and in the periphery. The involvement of brain-infiltrating immune cells and their subpopulations in the process of neuroinflammation and neurodegeneration, changes in the composition and phenotype of peripheral immune cells and their functional characteristics are discussed. Analysis of immune cell subsets and their ratios reveals subtle PD-specific changes in cellular populations that can be used as reliable biomarkers for diagnosis, prognosis of the disease course, and development of new approaches for anti-inflammatory and targeted therapies in PD.
AGE AND SEX CHARACTERISTICS OF THE BEHAVIOR OF PRENATALLY STRESSED RATS IN A BLACK-AND-WHITE MODIFICATION OF THE BEHAVIORAL MODEL “SUOK-TEST”
Authors: Kuleshova O. N.
Published: April 2024

Research activity, anxiety and motor disintegration were studied in prenatally stressed immature and adult male and female rats in the Suok-test model. The mothers of these animals from the 16th to the 19th days of pregnancy were placed for 3 hours in plastic pencil cases that fix the animals. The offspring were tested on day 20 and month 4 of postnatal ontogenesis. Mature females were tested taking into account the estrous cycle. A decrease in anxiety and an increase in research activity was observed in all experimental groups, with the exception of mature females at the diestrus stage. At this stage of the estrous cycle, behavioral patterns were identified in females that characterize anxiety and a decrease in the research component of behavior. Sensorimotor disintegration characteristic of immature animals was compensated with age, but not in females at the diestrus stage. Thus, according to the results of the study, it can be concluded that prenatal stress can carry both adaptive functions, causing the growth of the research component of behavior, and maladaptive ones. The anxiolytic effects of prenatal stress are rather negative, reducing evolutionarily significant protective mechanisms.
SALIFEN PREVENTS PERINATAL HYPOXIA-INDUCED COGNITIVE IMPAIRMENTS AND CHANGES IN GABAB RECEPTOR EXPRESSION IN THE RAT NEOCORTEX
Authors: Mironova V. I. , Pritvorova A. V. , Akulova V. K. , Mikhailenko V. A. , Otellin V. A. , Khozhai L. I. , Ordyan N. E.
Published: April 2024

We have studied the effects of acute normobaric hypoxia in the early postnatal period of the development (the 2nd postnatal day) on learning and memory abilities and the expression of GABAB receptors in the neocortex (medial prefrontal cortex) in adolescent rats (the 55–60th postnatal day), as well as the possibility of correction of the revealed impairments by GABA derivative salifen. It was shown that perinatal hypoxia disrupts task acquisition and consolidation in the novel object recognition test, impairs passive avoidance performance, and also reduces spatial learning abilities in the Morris water maze. Western blotting analysis revealed increased levels of GABAB receptor protein in the medial prefrontal cortex of the rats following the exposure to perinatal hypoxia. Post-hypoxic daily salifen injections over 14 days at a dose of 15 mg/kg improved cognitive abilities in rats, and also normalized GABAB receptor content in the rat medial prefrontal cortex. The results of the present research are of considerable significance for solution of applied problem of neonatology – the search for effective drug candidates for the pharmacological correction of the impacts of perinatal hypoxia.
BASIC AND SUPERORDINATE IMAGE CATEGORIZATION. INFLUENCE OF THE CONGRUENCE DEGREE AND TEMPORAL PARAMETERS OF PREVIOUS STIMULUS PRESENTATION
Authors: Gerasimenko N. Yu. , Kushnir A. B. , Mikhailova E. S.
Published: April 2024

The influence of temporal characteristics of mask presentation on performance in basic and superordinate image categorization tasks was investigated in young healthy subjects using a forward masking model. The masks could be congruent, noncongruent, or semantically neutral to the stimulus images. In the first series of experiments, the influence of stimulus onset asynchrony (SOA, the time interval between the onset of the mask and the onset of the stimulus) was studied. SOA varied from 100 to 350 ms in steps of 50 ms, whereas mask duration remained unchanged and equaled 100 ms. In the second series, the influence of mask duration was investigated. It varied from 100 to 250 ms in steps of 50 ms, while SOA remained constant at 250 ms. It was found that superordinate categorization was performed faster. This could be due to the fact that superordinate categorization involves a low-frequency information of stimulus description that is rapidly transmitted through the magnocellular visual pathway. The basic categorization was more sensitive to the temporal properties of the mask and its category. Changes in SOA had a stronger effect than those in mask duration. Assuming that SOA changes affect the early perceptual phase of stimulus processing, the sensitivity of this phase to irrelevant information seems to be reflected in the stronger influence of SOA changes on basic categorization compared to superordinate categorization.
COORDINATING ROLE OF ACTIN CYTOSKELETON IN SHORT-TERM PLASTICITY OF NEURAL ENSEMBLES INVOLVING EXCITATORY AND INHIBITORY SYNAPSES
Authors: Kudryashova I. V.
Published: April 2024

The problem of frequency coding is closely related to the studies of inhibitory transmission as a factor of neural network plasticity. The rewiew presents basic mechanisms of inhibitory control of spatio-temporal pattern of neural activity during signal processing. Current views are analyzed in respect of dynamic synapses, their instability and variation within the ongoing activity. The results presented here demonstrate that short-term plasticity operates with the combined contribution of excitatory and inhibitory synapses. The role of GABAergic potentials in modulation of intracellular messenger’s activity is discussed, including those implicated in postsynaptic modifications of excitatory and inhibitory transmission. The main topics concerning the molecular mechanisms centered on the lateral diffusion of GABAA receptors. The data of many reports argue for coordinating role of actin cytoskeleton. It is proposed that postsynaptic mechanisms underlying GABAA plasticity may be activated in result of fast adaptation of actin cytoskeleton and associated proteins to disbalance between excitation and inhibition.
PUPILLOMETRY IN THE ASSESSMENT OF EMOTIONAL STATE AND COGNITIVE FUNCTIONS IN HUMAN
Authors: Kutlubaev M. A. , Shagieva D. R. , Karimova G. I. , Izmalkova A. I. , Myachikov A. V.
Published: April 2024

Pupillometry is a method allowing quantitative assessment of the pupil diameter. The size of the pupil is regulated by the structures of autonomic nervous system (nuclei of the oculomotor nerve, ciliospinal center) and related to the ambient lighting. However, overlying structures of the brain, in particular cortex, via locus coeruleus, upper colliculi of quadrigeminal bodies modulate the pupillary response regardless ambient lighting condition. Thus the baseline diameter of the pupil and its changes associated with certain tasks could be used for the objective assessment of the emotional state and cognitive functions in a human. There are data showing the changes in the pupillary response in patients with autism spectrum disorder, depression as well as Alzheimer’s disease, Parkinson’s disease and other organic disorders of the brain. More research in pupillometry is needed to identify new areas for its use.
SEX DIFFERENCES IN SELECTIVE AUDITORY ATTENTION DURING DICHOTIC LISTENING WITH DIFFERENT LEVELS OF COMPLEXITY: AN FMRI STUDY
Authors: Mayorova L. A. , Kushnir A. B.
Published: April 2024

A group of 20 healthy subjects (11 males and 9 females) performed a selective auditory attention task in a dichotic listening paradigm with different levels of perceptual load. Analysis of brain activation patterns measured with fMRI during selective listening to fusion speech with distractors of varying strengths revealed statistically significant sex differences in the topography of cortical activity. “Female male” effects dominated in the left superior temporal gyrus and the left pre and postcentral gyrus; while the most pronounced “male female” effects were found in the left islet, shell and frontal lobule. Statistically significant effects were also obtained by comparing activation patterns according to the level of task complexity: It was shown that masking with a female speaker’s voice caused greater activation of additional high-level information processing areas. The findings indicate the presence of sexual dimorphism in the organization of the selective auditory attention system.
THE CONTRIBUTION OF EPIGENETIC MECHANISMS TO THE FORMATION, MAINTENANCE AND RECONSOLIDATION OF THE LONG-TERM FOOD AVERSIVE MEMORY IN TERRESTRIAL SNAIL
Authors: Zuzina А. B. , Balaban P. М.
Published: April 2024

This work was devoted to the analysis of the role of epigenetic mechanisms (histone acetylation, DNA methylation, histone serotonylation) in the formation, storage, and reconsolidation of long-term food aversive memory in the snail. In the first part of the work, we investigated the effect of systemic administration of sodium butyrate, an inhibitor of histone deacetylase, in a model of conditioned food aversion reflex of the snail. We have shown that the administration of sodium butyrate to animals with poor memory resulted in memory enhancement. Further, in experiments using the DNA methyltransferase blocker RG108, it was found that impaired DNA methylation impairs long-term food aversive memory in the snail. However, memory reactivation neutralizes the effect of inhibiting the activity of DNA methyltransferases. In the final section of the work, the hypothesis of the involvement of transglutaminase-mediated serotonylation in the processes of reconsolidation of food aversive memory in the snail was tested. Behavioral analysis showed that administration of the transglutaminase blocker monodansylcadaverine (hence, blockade of serotonylation) after a reminder disrupted the reconsolidation process and led to memory suppression/erasure.
DISORDERS OF MOTOR ACTIVITY ON THE MODEL OF AUTISM SPECTRUM DISORDERS
Authors: Khairullin A. E. , Efimova D. V. , Ivanova D. V. , Baltina T. V. , Baltin M. E. , Grishin S. N. , Ziganshin A. U.
Published: April 2024

Autism, or autism spectrum disorder (ASD), is a multifactorial disease that is characterized not only by disorders of the psycho-emotional state and social interaction, but also by somatic dysfunctions. A number of studies have also reported changes in the musculoskeletal system in patients with ASD. In this work, by the method of video analysis of movements, we demonstrated a decrease in horizontal and vertical motor activity, in addition, deviant movements were recorded, which indicates a violation in locomotor activity and increased anxiety in rats with a valproate model of autism. However, a mechano-myographic study did not reveal significant changes in the contractility parameters of isolated skeletal muscles of rats with the ASD model. Thus, it can be concluded that general differences in movement may be an independent factor in the diagnosis of autism. A more thorough study using a larger sample and detailed kinematic analysis can help in further assessing the variability of motor functions as a potential diagnostic and prognostic marker of ASD.
EFFECT OF CHLORAL HYDRATE ON MORPHOLOGICAL CHANGES IN THE NEOCORTEX AND FUNCTIONAL STATE OF OLD MALE RATS
Authors: Shcherbak N. S. , Yukina G. Yu. , Gurbo A. G. , Sukhorukova E. G. , Sargsian A. G. , Thomson V. V.
Published: April 2024

In order to avoid obtaining distorted results at the stage of preclinical study of new pharmaceutical substances and therapeutic strategies, it is necessary to take into account the features and possible influence of the age of the animal and the anesthesia used on the outcome of the experiment. We studied the effect of chloral hydrate on morphological changes in neurons and the reaction of neocortical microglia and the functional state of old male Wistar rats (24 months). Differences were assessed in control rats and in the group using chloral hydrate at the dose required to achieve anesthesia (400 mg/kg animal weight) after 48hours. After the application of chloral hydrate, the surviving animals (mortality rate 37.5%) showed a significant increase in the signs of neurological deficit in the form of motor, sensory and behavioral disorders compared to the rats of the control group. In the fronto-parietal region of the neocortex of the surviving animals, the expression level of the Iba-1 protein was significantly higher than in the control, neurons and microgliocytes with pronounced morphological changes were noted, while their number did not significantly differ from that in the control group. The obtained results suggest that the adverse effect in the early period after anesthesia with chloral hydrate without model surgical intervention in old rats, which manifests itself in the form of a deterioration in the functional state and mortality, can be realized due to the activation of microglia in the fronto-parietal region of the neocortex. However, the process of determining the specific structure of the brain, the activation of microglia in which is more responsible for the formation of neurological disorders, is quite complex and needs further study. In fundamental and preclinical studies of neuroprotective effects, in which old rats are used as the object of study and chloral hydrate is used as an anesthetic, these features must be taken into account.
MOTOR CONTROL AND COGNITIVE FUNCTIONS RECOVERY DURING FORCED AWAKENING FROM SLOW-WAVE DAYTIME SLEEP
Authors: Soloveva A. K. , Solovev N. K. , Mokrousova A. O. , Ukraintseva Yu. V.
Published: April 2024

The recovery mechanisms of various forms of behavior upon awakening from sleep are still not well understood. In this work, we investigated the recovery of simple motor reactions to visual stimuli, fine hand-eye coordination, and abstract thinking upon awakening from the deepest, SWS stage of daytime sleep. Subjects were offered two types of tasks: visual-motor tasks in which it was necessary to control a moving object; and arithmetic, in which it was necessary to determine the correctness of the proposed equalities in wakefulness before sleep and during the first 2 minutes of awakening from sleep. The results obtained showed that the speed of a simple motor reaction to the appearance of a visual stimulus reached the wakefulness level almost immediately after awakening (within 4 seconds), while the restoration of the ability to determine the correctness or incorrectness of arithmetic equalities, as well as the ability to accurately control the trajectory of a moving object required much more time: about 40 seconds (in the arithmetic task) and 60 seconds (in the visual-motor task). The power of the alpha-rhythm upon awakening was higher than in wakefulness. Delta-rhythm power was increased only at the beginning of awakening while task performing was difficult, and in the second minute of awakening the delta-rhythm decreased when task performing was restored. Our data indicate that simple and complex forms of behavior upon awakening are not restored simultaneously.
Increase in histone acetylation rescues a weak remote fear memory in rats
Authors: Vinarskaya A. Kh. , Balaban P. M. , Zuzina A. B.
Published: April 2024

There is a growing body of evidence of memory-enhancing effects of histone deacetylase (HDAC) inhibitors in different species and models. Less clearly is understood whether the increased histone acetylation is able to facilitate the remote fear memory. Thus, the aim of the current study was to examine the ability of HDAC inhibitor sodium butyrate (SB) to ameliorate weakening of the remote fear memory in rats. To assess the ability of HDAC inhibitor SB to improve remote fear memory we compared the performance of two laboratory strains of rats, Wistar and Long-Evans, in context fear conditioning task six months after training before and after the SB administration. We found that the rats showed a strong fear response to the context 24 h after the end of conditioned fear training, full absence of fear after 6 months, and high fear response after the SB administration without additional learning. In control experiments, we found that time-dependent decrease in conditioned fear response to the context was similar in rats under vehicle administration. Moreover, the data obtained showed that both rats’ strains showed a similar decrease in freezing response over time, and HDAC inhibition improved the weak remote fear memory in both of them. In addition, the decrease in freezing and memory reinstatement by males matched completely to the female rats’ performance. These results indicate that HDAC inhibition appears to have the same “rescue” effects on remote fear memory reinstatement regardless of the strain and gender of rats.
Solution Uniqueness Criteria in a Time-Nonlocal Problem for the Operator Differential Equation l(.)-A with the Tricomi Operator A
Authors: Kanguzhin B. E , Koshanov B. D
Published: April 2024

We study the uniqueness of the solution of a time-regular problem for the operator-differential equation with the Tricomi operator. The order of the differential expression is considered to be an arbitrary positive integer, and the regular boundary conditions are given with respect to the time variable. The operator is generated by the Tricomi equation. The boundary conditions for the Tricomi operator are given by the Dirichlet condition on the elliptic part and by the fractional derivative traces of the solution along the characteristics. It is indicated that this operator is a self-adjoint operator in the space. The self-adjointness of the operator guarantees the existence of a complete system of eigenfunctions orthonormal in if is a domain bounded by a Lyapunov curve and by characteristics of the wave equation.
Numerical Construction of the Transform of the Kernel of the Integral Representation of the Poincaré–Steklov Operator for an Elastic Strip
Authors: Bobylev A. A
Published: April 2024

For an isotropic stratified elastic strip we consider the Poincaré–Steklov operator that maps normal stresses into normal displacements on part of the boundary. A new approach is proposed for constructing the transform of the kernel of the integral representation of this operator. A variational formulation of the boundary value problem for the transforms of displacements is obtained. A definition is given and the existence and uniqueness are proved for a generalized solution of the problem. An iteration method for solving variational equations is constructed, and conditions for its convergence are obtained based on the contraction mapping principle. The variational equations are approximated by the finite element method. As a result, at each step of the iteration method, it is required to solve two independent systems of linear algebraic equations, which are solved using the tridiagonal matrix algorithm. A heuristic algorithm is proposed for choosing the sequence of parameters of the iteration method that ensures its convergence. Verification of the developed computational algorithm is carried out, and recommendations on the use of adaptive finite element grids are given
On the Spectral Properties of a Fourth-Order Self-Adjoint Operator
Authors: Polyakov D. M
Published: April 2024

We consider a spectral problem for a fourth-order differential operator with real periodic coefficients and Neumann-type boundary conditions. For this operator, the eigenvalue asymptotics and a regularized trace formula are obtained.
On the Absence of Solutions of Differential Inequalities with the
-Laplacian
Authors: Kon'kov A. A
Published: April 2024

For differential inequalities with the ∞-Laplacian in the principal part, we find conditions for the absence of solutions in unbounded domains. Examples are given that demonstrate the accuracy of these conditions.
Stability Criterion and Sharp Estimates for the “Super-Twisting” Algorithm
Authors: Fomichev V. V , Vysotskiy A. O
Published: April 2024

A new method for proving necessary and sufficient conditions for the global asymptotic stability of the “super-twisting” algorithm is given. The new method is based on obtaining a complete analytical solution of the system for the “worst-case” perturbation and permits one to obtain a criterion in a simpler, completely real form as well as to find estimates for the worst-case (majorizing) trajectory.
On the Exact Controllability of a Semilinear Evolution Equation with an Unbounded Operator
Authors: Chernov A. V
Published: April 2024

For the Cauchy problem associated with a controlled semilinear evolution equation with an unbounded maximal monotone operator in a Hilbert space, sufficient conditions are obtained for exact controllability to a given final state. Here a generalization of the Browder–Minty theorem and results on the total global solvability of this equation obtained by the author earlier are used. As an example, a semilinear wave equation is considered.
On the Preservation of a Quadratic Lyapunov Function of a Linear Differential Autonomous System under Constant Perturbations of the Coefficients
Authors: Antonovskaya O. G
Published: April 2024

For an autonomous linear homogeneous asymptotically stable differential system, we obtain sufficient conditions for the smallness of perturbations in the class of autonomous linear homogeneous systems under which a quadratic form that is a Lyapunov function of the original system remains a Lyapunov function of the perturbed system.
A Nonlocal Problem with an Integral Matching Condition for a Loaded Parabolic-Hyperbolic Equation with a Fractional Caputo Derivative
Authors: Abdullaev O. Kh
Published: April 2024

A nonlocal problem with an integral matching condition is studied for a parabolic-hyperbolic equation with two lines of type change containing a nonlinear loaded term. The uniqueness of the solution of the problem is proved by the method of energy integrals and the existence, using the theory of integral equations. Classes and sufficient conditions are determined for given functions that ensure the unique solvability of the problem under study.
On the Solvability of a System of Nonlinear Integral Equations with the Hammerstein–Stieltjes Operator on the Half-Line
Authors: Khachatryan Kh. A , Petrosyan A. S
Published: April 2024

We study a system of nonlinear integral equations of the Hammerstein–Stieltjes type whose pre-kernels are continuous distribution functions. A constructive existence theorem for a nontrivial, nonnegative, and bounded solution of the system is proved. The integral asymptotics of the constructed solution is studied. Examples of systems for which all the conditions of the theorem are satisfied are given.