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A A Zaikin

Publications and source records attributed to A A Zaikin.

13 recordsLinked to original sources
PubMed2006

Noise-induced inhibitory suppression of frequency-selective stochastic resonance.

We study the control of oscillations in a system of inhibitory coupled noisy excitable and oscillatory units. Using dynamical properties of inhibition, we find regimes when the oscillations can be suppressed but the information signal of a certain frequency can be transmitted through the system. The mechanism of this phenomenon is a resonant interplay of noise and the transmission signal provided by certain value of inhibitory coupling. Analyzing a system of three or four oscillators representing neural clusters, we show that this suppression can be effectively controlled by coupling and noise amplitudes.

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PubMed2003

Frequency-dependent stochastic resonance in inhibitory coupled excitable systems.

We study frequency selectivity in noise-induced subthreshold signal processing in a system with many noise-supported stochastic attractors which are created due to slow variable diffusion between identical excitable elements. Such a coupling provides coexisting of several average periods distinct from that of an isolated oscillator and several phase relations between elements. We show that the response of the coupled elements under different noise levels can be significantly enhanced or reduced by forcing some elements in resonance with these new frequencies which correspond to appropriate phase relations.

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PubMed2003

Oscillatory amplification of stochastic resonance in excitable systems.

We study systems which combine both oscillatory and excitable properties, and hence intrinsically possess two internal frequencies, responsible for standard spiking and for small amplitude oscillatory limit cycles (Canard orbits). We show that in such a system the effect of stochastic resonance can be amplified by application of an additional high-frequency signal, which is in resonance with the oscillatory frequency. It is important that for this amplification one needs much lower noise intensities as for conventional stochastic resonance in excitable systems.

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PubMed2003

Coherence resonance and polymodality in inhibitory coupled excitable oscillators.

We have analyzed the firing activity of two and three excitable FitzHugh-Nagumo oscillators, coupled via slow variable diffusion and under the action of an external noise. We find a different form of coherence resonance in this system, which is, in contrast to previous studies, intrinsically based on the antiphase behavior of coupled elements. Additionally, we show that an exchange, performed by this form of coupling, is remarkably rhythmogenic and results in polymodal interspike distributions without any external periodic stimuli. The dependence of these distributions on the noise amplitude and the coupling strength is studied.

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PubMed2002

Vibrational resonance in a noise-induced structure.

We report on the effect of vibrational resonance in a spatially extended system of coupled noisy oscillators under the action of two periodic forces, a low-frequency one (signal) and a high-frequency one (carrier). Vibrational resonance manifests itself in the fact that for optimally selected values of high-frequency force amplitude, the response of the system to a low-frequency signal is optimal. This phenomenon is a synthesis of two effects, a noise-induced phase transition leading to bistability, and a conventional vibrational resonance, resulting in the optimization of signal processing. Numerical simulations, which demonstrate this effect for an extended system, can be understood by means of a zero-dimensional "effective" model. The behavior of this "effective" model is also confirmed by an experimental realization of an electronic circuit.

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PubMed2001

Noise induced propagation in monostable media.

We show that external fluctuations are able to induce propagation of harmonic signals through monostable media. This property is based on the phenomenon of doubly stochastic resonance, where the joint action of multiplicative noise and spatial coupling induces bistability in an otherwise monostable extended medium, and additive noise resonantly enhances the response of the system to a harmonic forcing. Under these conditions, propagation of the harmonic signal through the unforced medium is observed for optimal intensities of the two noises. This noise-induced propagation is studied and quantified in a simple model of coupled nonlinear electronic circuits.

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PubMed2001

Simple electronic circuit model for doubly stochastic resonance.

We have recently reported the phenomenon of doubly stochastic resonance [Phys. Rev. Lett. 85, 227 (2000)], a synthesis of noise-induced transition and stochastic resonance. The essential feature of this phenomenon is that multiplicative noise induces a bimodality and additive noise causes stochastic resonance behavior in the induced structure. In the present paper we outline possible applications of this effect and design a simple lattice of electronic circuits for the experimental realization of doubly stochastic resonance.

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PubMed1999

Nonequilibrium first-order phase transition induced by additive noise.

We show that a nonequilibrium first-order phase transition can be induced by additive noise. As a model system to study this phenomenon, we consider a nonlinear lattice of overdamped oscillators with both additive and multiplicative noise terms. Predictions from mean field theory are successfully confirmed by numerical simulations. A physical explanation for the mechanism of the transition is given.

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PubMedDate not supplied

[Direct phenol-hypochlorite method for determining glutaminase activity].

A simple and sensitive method is developed to determine the glutaminase activity. Conditions are selected for detecting enzymatically formed ammonia in the presence of such a high-labile substrate as glutamine. The method is simple in performance, readily reproducible and high-sensitive.

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