Susan Gordleeva

• PhD
• N. I. Lobachevsky State University of Nizhny Novgorod

In this paper, we propose a spiking neural network model with Hebbian connectivity for implementing energy-efficient associative memory, whose activity is determined by input stimuli. The model consists of three interacting layers of Hodgkin–Huxley–Mainen spiking neurons with excitatory and inhibitory synaptic connections. Information patterns are...

Perceptual decision-making enables humans to process sensory information and translate it into goal-directed actions. A critical component of this process is response time, which declines with age due to the slowing of both non-decision processes and evidence accumulation. While perceptual learning has been shown to counteract these declines, it re...

The purpose of this work is to study the role of mechanisms of astrocytic regulation of synaptic transmission in the processes of synchronization formation in signaling of neural networks by mathematical modeling methods. Methods. The paper presents a model of a small neuron-astrocyte ensemble. The HodgkinHuxley model is used as a model of the memb...

Low-threshold mechanoreceptors (LTMRs) are specialized sensory neurons responsible for transmitting tactile information to the brain. These receptors exhibit diverse characteristics in terms of conduction velocity, myelination, and adaptation to pressure, enabling them to encode a wide range of tactile experiences. This study presents a simplified...

The purpose of this work is to study the effects of spatio-temporal dynamics of spontaneous calcium signaling in the morphological structure of an astrocyte at the subcellular level using biophysical mathematical modeling methods. Methods. This work proposes a biophysical multicompartmental model of noise-induced calcium dynamics in the astrocytic...

The aftermath of a stroke can frequently result in impaired motor functions causing problems performing habitual limb movements. These movement disorders stem from damage to the cerebral cortex and disruptions to neuronal connections in the central pyramidal pathways [1]. Restoring motor skills following a stroke is a time-consuming and challenging...

The examination of synchronization in neural networks is essential to comprehend how the brain functions in normal and pathological states. The synchronization of signals between groups of neurons is paramount for brain activity and associated with various brain functions, including memory, movement, sleep, and attention. However, a balance between...

Motor imagery is a widely used technique in neurophysiological research and brain–computer interface applications for restoring lost motor functions. This study aimed to analyze the neural correlates of motor imagery at the level of brain functional networks using electroencephalography (EEG). Thirty subjects performed motor executions, quasi-movem...

Tactile perception is a fundamental sensory system, playing a pivotal role in our understanding of the surrounding environment and aiding in motor control. In this study, we investigated the distinct neural underpinnings of discriminative touch, affective touch (specifically the C tactile system), and knismesis. We developed a paradigm of EEG exper...

Tactile perception encompasses several submodalities that are realized with distinct sensory subsystems. The processing of those submodalities and their interactions remains understudied. We developed a paradigm consisting of three types of touch tuned in terms of their force and velocity for different submodalities: discriminative touch (haptics),...

The control of movement in living organisms represents a fundamental task that the brain has evolved to solve. One crucial aspect is how the nervous system organizes the transformation of sensory information into motor commands. These commands lead to muscle activation and subsequent animal movement, which can exhibit complex patterns. One example...

A miniature postsynaptic current (mPSC) is a small, rare, and highly variable spontaneous synaptic event that is generally caused by the spontaneous release of single vesicles. The amplitude and variability of mPSCs are key measures of the postsynaptic processes and are taken as the main characteristics of an elementary unit (quantal size) in tradi...

When viewing a completely ambiguous image, different interpretations can switch involuntarily due to internal top-down processing. In the case of the Necker cube, an entirely ambiguous stimulus, observers often display a bias in perceptual switching between two interpretations based on their perspectives: one with a from-above perspective (FA) and...

Experiments show activation of the left dorsolateral prefrontal cortex (DLPFC) in motor imagery (MI) tasks, but its functional role requires further investigation. Here, we address this issue by applying repetitive transcranial magnetic stimulation (rTMS) to the left DLPFC and evaluating its effect on brain activity and the latency of MI response....

In this study, we investigated the neural and behavioral mechanisms associated with precision visual-motor control during the learning of sport shooting. We developed an experimental paradigm adapted for naïve individuals and a multisensory experimental paradigm. We showed that in the proposed experimental paradigms, subjects trained well and signi...

Neuro- and biomorphic approaches in the design of intelligent robotic systems and, more specifically, various technical applications have attracted much attention from researchers and engineers. Biomorphic robotics implies that a machine should be able to reproduce movement and control it the same way animals do in a real-world environment. Fish-li...

We show that unavoidable stochastic fluctuations are not only affecting information processing in a destructive or constructive way, but may even induce conditions necessary for the artificial intelligence itself. In this proof-of-principle paper we consider a model of a neuron-astrocyte network under the influence of multiplicative noise and show...

Recent experimental works revealed that astrocytes are the critical players involved in dynamic interaction with neurons in information processing and storage. Several studies provided direct evidence of the involvement of abnormal astrocytic signaling in cognitive impairment. Astroglial atrophy is observed in many age-dependent neurodegenerative d...

Working memory refers to the capability of the nervous system to selectively retain short-term memories in an active state. The long-standing viewpoint is that neurons play an indispensable role and working memory is encoded by synaptic plasticity. Furthermore, some recent studies have shown that calcium signaling assists the memory processes and t...

We trained an artificial neural network (ANN) to distinguish between correct and erroneous responses in the perceptual decision-making task using 32 EEG channels. The ANN input took the form of a 2D matrix where the vertical dimension reflected the number of EEG channels and the horizontal one—to the number of time samples. We focused on distinguis...

Working memory refers to the capability of the nervous system to selectively retain short-term memories in an active state. The long-standing viewpoint is that neurons play an indispensable role and working memory is encoded by synaptic plasticity. Furthermore, some recent studies have shown that calcium signaling assists the memory processes and t...

Cardiovascular diseases associated with high cholesterol (hypercholesterolemia) and low-density lipoproteins (LDL) levels are significant contributors to total mortality in developing and developed countries. Mathematical modeling of LDL metabolism is an important step in the development of drugs for hypercholesterolemia. The aim of this work was t...

Modeling the neuronal processes underlying short-term working memory remains the focus of many theoretical studies in neuroscience. In this paper, we propose a mathematical model of a spiking neural network (SNN) which simulates the way a fragment of information is maintained as a robust activity pattern for several seconds and the way it completel...

Recent in vitro and in vivo experiments demonstrate that astrocytes participate in the maintenance of cortical gamma oscillations and recognition memory. However, the mathematical understanding of the underlying dynamical mechanisms remains largely incomplete. Here we investigate how the interplay of slow modulatory astrocytic signaling with fast s...

In this work, we consider a mathematical model describing spontaneous calcium signaling in astrocytes. Based on biologically relevant principles, this model simulates experimentally observed calcium oscillations and can predict the emergence of complicated dynamics. Using analytical and numerical analysis, various attracting sets were found and inv...

Mammalian brains operate in a very special surrounding: to survive they have to react quickly and effectively to the pool of stimuli patterns previously recognized as danger. Many learning tasks often encountered by living organisms involve a specific setup centered around a relatively small set of patterns presented in a particular environment. Fo...

Mammalian brains operate in a very special surrounding: to survive they have to react quickly and effectively to the pool of stimuli patterns previously recognized as danger. Many learning tasks often encountered by living organisms involve a specific set-up centered around a relatively small set of patterns presented in a particular environment. F...

All vertebrates are capable of performing various types of physical activity. Locomotor patterns are created by the cyclical coordinated work of the skeletal muscles. The organization of such a system in living organisms is responsible for networks of interconnected populations of neurons capable of forming rhythmic activity - CPG. As biologists ha...

Modeling the neuronal processes underlying short-term working memory remains the focus of many theoretical studies in neuroscience. Here we propose a mathematical model of spiking neuron network (SNN) demonstrating how a piece of information can be maintained as a robust activity pattern for several seconds then completely disappear if no other sti...

In this study, we address the issue of whether vibrotactile feedback can enhance the motor cortex excitability translated into the plastic changes in local cortical areas during motor imagery (MI) BCI-based training. For this purpose, we focused on two of the most notable neurophysiological effects of MI – the event-related desynchronization (ERD)...

The purpose of this review is to observe the current state of research on sensorimotor integration in the human brain during visual perception and subsequent decision-making under conditions of ambiguous information. Methods. This review examines the approaches of time-frequency wavelet analysis for brain activity when performing perceptual tasks,...

Working memory is one of the most intriguing brain function phenomena that enables storage and recognition of several information patterns simultaneously in the form of coherent activations of specific brain circuitries. These patterns can be recalled and, if physiologically (cognitively) significant, further transferred to long term storages by co...

Recent experimental data show that neural network dynamics significantly depends on the properties of an active nonlinear environment in the brain. Chemical activity of astrocytes is one of the main factor modifying the excitability of the neuronal membrane and regulating the efficiency of signal transmission between neurons. It is known that astro...

The purpose of this work is to show the mechanisms of transitions between different dynamic modes of spontaneous astrocytic calcium activity. With this aim, dynamics of recently introduced Lavrentovich-Hemkin mathematical model was examined by both analytical and numerical techniques. Methods. In order to obtain the conditions for the oscillations...

Goal. The paper is devoted to controlling the dynamics of spike neural networks by local periodic stimulation of various network sections. Methods. The simulation uses a network of synaptically connected spike neurons distributed in two-dimensional space. The dynamics of the transmembrane potential of neurons is described by the Izhikevich model, s...

We propose a novel biologically plausible computational model of working memory (WM) implemented by a spiking neuron network (SNN) interacting with a network of astrocytes. The SNN is modeled by synaptically coupled Izhikevich neurons with a non-specific architecture connection topology. Astrocytes generating calcium signals are connected by local...

In this study, we address the issue of whether vibrotactile feedback can enhance the motor cortex excitability translated into the plastic changes in local cortical areas during motor imagery (MI) BCI-based training. For this purpose, we focused on two of the most notable neurophysiological effects of MI – the event-related-desynchronization (ERD)...

There is growing evidence that suggests the importance of astrocytes as elements for neural information processing through the modulation of synaptic transmission. A key aspect of this problem is understanding the impact of astrocytes in the information carried by compound events in neurons across time. In this paper, we investigate how the astrocy...

In this work, an integrated mathematical model of the liver cell, cholesterol metabolism, and drug interactions was developed. The model reproduced the well-known biology of cholesterol regulation, which confirms its potential for minimizing cellular research in the initial testing of new drugs for cardiology.

Integrated information has been recently suggested as a possible measure to identify a necessary condition for a system to display conscious features. Recently, we have shown that astrocytes contribute to the generation of integrated information through the complex behavior of neuron–astrocyte networks. Still, it remained unclear which underlying m...

We propose a biologically plausible computational model of working memory (WM) implemented by the spiking neuron network (SNN) interacting with a network of astrocytes. SNN is modelled by the synaptically coupled Izhikevich neurons with a non-specific architecture connection topology. Astrocytes generating calcium signals are connected by local gap...

Brain aging is a complex process involving many functions of our body and described by the interplay of a sleep pattern and changes in the metabolic waste concentration regulated by the microglial function and the glymphatic system. We review the existing modelling approaches to this topic and derive a novel mathematical model to describe the cross...

Brain aging is a complex process involving many functions of our body and described by the interplay of a sleep pattern and changes in the metabolic waste concentration regulated by the microglial function and the glymphatic system. We review the existing modelling approaches to this topic and derive a novel mathematical model to describe the cross...

In this paper, we study the role of astrocyte-induced modulation of signal transmission in network of synaptically coupled spiking neurons in the mechanisms of the short-term memory formation. We show, that due to the local spatial synchronization of signaling in the neural network induced by the astrocyte during the duration of the Ca 2+ signal, t...

Biological aging is a complex process involving multiple biological processes. These can be understood theoretically though considering them as individual networks—e.g., epigenetic networks, cell-cell networks (such as astroglial networks), and population genetics. Mathematical modeling allows the combination of such networks so that they may be st...

We investigate one aspect of the functional role played by astrocytes in neuron-astrocyte networks present in the mammal brain. To highlight the effect of neuron-astrocyte interaction, we consider simplified networks with bidirectional neuron-astrocyte communication and without any connections between neurons. We show that the fact, that astrocyte...

This article presents a rehabilitation technique based on a lower-limb exoskeleton integrated with a human–machine interface (HMI). HMI is used to record and process multimodal signals collected using a foot motor imagery (MI)-based brain–machine interface (BMI) and multichannel electromyographic (EMG) signals recorded from leg muscles. Current sol...

This study presents a comprehensive analytic description in terms of the empirical "whole minus sum" version of Integrated Information in comparison to the "decoder based" version for the "spiking-bursting" discrete-time, discrete-state stochastic model, which was recently introduced to describe a specific type of dynamics in a neuron-astrocyte net...

We investigate one aspect of the functional role played by astrocytes in neuron-astrocyte networks present in the mammal brain. To highlight the effect of neuron-astrocyte interaction, we consider simplified networks with bidirectional neuron-astrocyte communication and without any connections between neurons. We show that the fact, that astrocyte...

In this study, we consider the problem of signal processing in neuron–astrocyte networks where the intercellular communication is described on the basis of a tripartite synapse concept. This type of communication involves combined contributions of pre- and postsynaptic neuronal compartments and components of the surrounding astrocyte to the process...

The functional role of astrocyte calcium signaling in brain information processing was intensely debated in recent decades. This interest was motivated by high resolution imaging techniques showing highly developed structure of distal astrocyte processes. Another point was the evidence of bi-directional astrocytic regulation of neuronal activity. T...

The study has assayed a new type of brain–computer interface technology based on the P300 wave (BCI–P300), in which an artificial hand with moving fingers was used as an executive device, and flashes of LEDs located on each finger were used as visual stimuli. The focus of the subject’s attention on particular LED flashes on the finger subjectively...

Astrocytes express a complex repertoire of intracellular Ca²⁺ transients (events) that represent a major form of signaling within individual cells and in astrocytic syncytium. These events have different spatiotemporal profiles, which are modulated by neuronal activity. Spontaneous Ca²⁺ events appear more frequently in distal astrocytic processes a...

Integrated information is a quantitative measure from information theory of how tightly all parts of a system are interconnected in terms of information exchange. In this study we show that astrocytes, playing an important role in regulation of information transmission between neurons, may contribute to a generation of positive integrated informati...

We use tools of bifurcation theory to characterize dynamics of astrocytic IP\(_3\) and Ca\(^{2+}\) for different IP\(_3\) regimes. We do so starting from a compact, well-stirred astrocyte model to first identify characteristic IP\(_3\) pathways whereby Ca\(^{2+}\) and IP\(_3\) dynamics “bifurcate,” namely their dynamics changes from stable (constan...

Primary immunodeficiency diseases (PID) is a heterogeneous group of disorders caused by genetic defects of the immune system, which manifests clinically as recurrent infections, autoimmune diseases, or malignancies. Early detection of other PID remains a challenge, particularly in older children due to milder and less specific symptoms, a low level...

The aims of the study were to develop a vehicle with elements of neural-control for people with limited mobility and to test algorithms for transforming human bioelectric activity into the driving commands. Results. A running model of the first urban electric vehicle (neuro-mobile) with elements of neural-control and neuro-assistance intended for p...

Brain–computer interfaces (BCI) based on motor imagery allow people to use mental motor images recognized from the electroencephalogram (EEG) as control commands. With the aim of providing the most effective channel for interactions, interfaces of this type are under active development and modifi cation, though all currently require use of the visu...

We study dynamics of a spiking network of synaptically connected bistable neuronal oscillators. We find that delays in axonal conduction result in the emergence of coexisting states with high and low activity levels (up and down states). In the network, where cellular bistability is present, propagation delays and noise play a crucial role in the e...

One of the approaches in rehabilitation after a stroke is mental training by representation of movement using a brain-computer interface (BCI), which allows one to control the result of every attempt of imaginary movement. BCI technology is based on online analysis of an electroencephalogram (EEG), detecting moments of imaginary movement representa...

Astrocytes express a complex repertoire of intracellular Ca ²⁺ transients (events) that represent a major form of signaling within individual cells and in the astrocytic syncytium. These events have different spatiotemporal profiles, which are modulated by neuronal activity. Spontaneous Ca ²⁺ events appear more frequently in distal astrocytic proce...

The Integrated Information is a quantitative measure from information theory how tightly all parts of a system are interconnected in terms of information exchange. In this study we show that astrocyte, playing an important role in regulation of information transmission between neurons, may contribute to a generation of positive Integrated Informati...

In this study we compared tactile and visual feedbacks for the motor imagery-based brain–computer interface (BCI) in five healthy subjects. A vertical green bar from the center of the fixing cross to the edge of the screen was used as visual feedback. Vibration motors that were placed on the forearms of the right and the left hands and on the back...

The principles and mechanisms of information processing in the brain are among key fundamental problems of modern science. Neurons being the main signal cells of the brain provide the transmission and transformation of sequences of electrical pulses in a neural network. Signal networks include not only neurons but also glial cells called astrocytes...