ISSN 0869-6632 (Print)
ISSN 2542-1905 (Online)

Нелинейная динамика и нейронаука

Wavelet analysis of sleep spindles on eeg and development of method for their automatic diagnostic

The detailed wavelet analysis of sleep electric brain activity, obtained from rats with genetic predisposition to absence-epilepsy, has been performed. Characteristic features of time-and-frequency structure of sleep spindles (oscillatory pattern, that serve as electroencephalographic correlate for slow-wave sleep) have been discovered in long-term electroencephalographic data. Operation has been performed using continuous wavelet transform.

Dynamics of local potentials of brain at the absence-epilepsy: empirical modelling

The EEG research technique on the basis of autoregressive models construction and Granger causality estimation by experimental data are described in this article. The EEG is written down from the brain of WAG/Rij rats, which are absence-epilepsy contaminated. The EEG episodes well enough described in terms of small order linear display along with the episodes with expressed nonlinearity are revealed during the analysis. The EEG episodes ordering is spent in accordance with the model parameters received and physio-logical condition of the animals.

Autonomous and nonautonomous dynamics of functional model of serotonergic neuron

Serotonin is a key modulator of neuronal activity both at the system level and at the level of local (short­range) interactions. However, in contrast to the synaptically connected neuron ensembles, there are much less qualitative models that describe the serotonin­controlled neural circuits.

Creativity – unpredictability and information production

It is possible or not using formulas to penetrate the most intimate sphere of human cognitive functions – his creative laboratory. After all, even the air in this sphere filled with ambiguity and  improvisation. In the last three-five years, such attempts are verysuccessfully taken by the  physiologists, psychologists and experts in nonlinear physics. In this article we look at two examples  of creative processes – writing poems and jazz improvisation.

A neural network as a predictor of the discrete map

The possibility of predicting the regular and chaotic dynamics of a discrete map by using artificial neural network is studied. The method of error back­propagation is used for calculation the coefficients of the multilayer network. The predicting properties of the neural network are explored in a wide region of the system parameter for both regular and chaotic behaviors. The dependance of the prediction accuracy from the degree of chaos and from the number of layers of the network is studied.

Oscillatory instability and spontaneous subthreshold oscillations in a network of diffusively coupled calcium oscillators

The paper is devoted to the investigation of the dynamics of a network of interacting astrocytes. The astrocytes represent brain glial cells capable to generate chemical activity signals (calcium pulses). Similarly to nerve cells (neurons) the astrocytes form networksof interacting units coupled by means of gap junctions. The junctions represent special protein channels providing the di?usion of chemically active species between neighboring cells.

The phenomenon of self-referential phase reset in ensembles of interacting fitzhugh–nagumo neurons

The phenomenon of self-referential phase reset are investigated in ensembles of interacting FitzHugh–Nagumo neurons with di?erent topology of couplings. It is shown that the reset phase of neurons oscillation is independent of the initial phase and is de?ned by the stimulus parameters. This process does not require direct in?uence on all elements of the ensemble and takes place when stimulus is applied to one of the interacting neurons only. The in?uence of inter-neuron couplings and stimulus parameters on ensemble dynamics and phase reset phenomenon is studied.

Regular and chaotic oscillations in astrocyte model with regulation of calcium release kinetics

The dynamics of an astrocyte model is investigated. The astrocytes represent a type of glial cells regulating oscillations of major signaling cells, e.g. neurons. Subserved by complex molecular mechanisms the astrocytes generate calcium auto-oscillations which, in turn, are associated with the release of neuroactive chemicals into extracellular space. At variance with classical astrocyte models the three-component model considered takes into account a regulation of calcium release due to nonlinear dynamics of inositol-1,4,5 trisphosphate (IP3).

Feature of simultaneous influence of excitatory synaptic currents on a neuron with differential responses

The simultaneous influence of excitatory synaptic stimuli (the tonic AMPA and NMDA currents) on the neuron model with response differentiation is studied. It is shown that different types of neuron activity (rest state, low frequency or high frequency firing) are observed depending on the conductance of the AMPA and NMDA receptors. It is found that for the certain parameters values if both types of receptors are activated simultaneously, it is possible to obtain maximal frequency to be approximately 20% greater than that with the NMDA current alone.

Alternative methods for spiral wave chaos control and suppressing in cardiac models

We investigate elements, which describes the Luo–Rudy model equations. We ana?lyze the influence of different parameters for the spiral wave chaos properties.We analyze the effect of (i) constant current influence, (ii) calcium channels blocking, (iii) potassium channels activating. We present the histograms of the middle frequencies of elements, when the spiral wave chaos takes place.