oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

3 ( 1 )

2019 ( 11 )

2018 ( 8 )

2017 ( 9 )

Custom range...

Search Results: 1 - 10 of 7489 matches for " Claudio Mirasso "
All listed articles are free for downloading (OA Articles)
Page 1 /7489
Display every page Item
System size coherence resonance
Raul Toral,Claudio Mirasso,James D. Gunton
Physics , 2002,
Abstract: We show the existence of a system size coherence resonance effect for an ensemble of globally coupled excitable systems. Namely, we demonstrate numerically that the regularity in the signal emitted by an ensemble of globally coupled Fitzhugh-Nagumo systems, under excitation by independent noise sources, is optimal for a particular value of the number of coupled systems. This resonance is shown through several different dynamical measures: the time correlation function, correlation time and jitter.
Lyapunov Potential Description for Laser Dynamics
Catalina Mayol,Raul Toral,Claudio R. Mirasso
Physics , 1999, DOI: 10.1103/PhysRevA.59.4690
Abstract: We describe the dynamical behavior of both class A and class B lasers in terms of a Lyapunov potential. For class A lasers we use the potential to analyze both deterministic and stochastic dynamics. In the stochastic case it is found that the phase of the electric field drifts with time in the steady state. For class B lasers, the potential obtained is valid in the absence of noise. In this case, a general expression relating the period of the relaxation oscillations to the potential is found. We have included in this expression the terms corresponding to the gain saturation and the mean value of the spontaneously emitted power, which were not considered previously. The validity of this expression is also discussed and a semi-empirical relation giving the period of the relaxation oscillations far from the stationary state is proposed and checked against numerical simulations.
Mechanisms of Zero-Lag Synchronization in Cortical Motifs
Leonardo L. Gollo ,Claudio Mirasso,Olaf Sporns,Michael Breakspear
PLOS Computational Biology , 2014, DOI: doi/10.1371/journal.pcbi.1003548
Abstract: Zero-lag synchronization between distant cortical areas has been observed in a diversity of experimental data sets and between many different regions of the brain. Several computational mechanisms have been proposed to account for such isochronous synchronization in the presence of long conduction delays: Of these, the phenomenon of “dynamical relaying” – a mechanism that relies on a specific network motif – has proven to be the most robust with respect to parameter mismatch and system noise. Surprisingly, despite a contrary belief in the community, the common driving motif is an unreliable means of establishing zero-lag synchrony. Although dynamical relaying has been validated in empirical and computational studies, the deeper dynamical mechanisms and comparison to dynamics on other motifs is lacking. By systematically comparing synchronization on a variety of small motifs, we establish that the presence of a single reciprocally connected pair – a “resonance pair” – plays a crucial role in disambiguating those motifs that foster zero-lag synchrony in the presence of conduction delays (such as dynamical relaying) from those that do not (such as the common driving triad). Remarkably, minor structural changes to the common driving motif that incorporate a reciprocal pair recover robust zero-lag synchrony. The findings are observed in computational models of spiking neurons, populations of spiking neurons and neural mass models, and arise whether the oscillatory systems are periodic, chaotic, noise-free or driven by stochastic inputs. The influence of the resonance pair is also robust to parameter mismatch and asymmetrical time delays amongst the elements of the motif. We call this manner of facilitating zero-lag synchrony resonance-induced synchronization, outline the conditions for its occurrence, and propose that it may be a general mechanism to promote zero-lag synchrony in the brain.
Phase-shifts in stochastic resonance in a Chua circuit
Wojciech Korneta,Iacyel Gomes,Claudio R. Mirasso,Raul Toral
Physics , 2007,
Abstract: We present an experimental study of stochastic resonance in an electronic Chua circuit operating in the chaotic regime. We study in detail the switch-phase distribution and the phase-shift between sinusoidal forcing for two responses of the circuit: one depending on both inter-well and intra-well dynamics and the other depending only on inter-well dynamics. We describe the two relevant de-synchronizatrion mechanisms for high and low frequencies of the forcing and present a method to detect the optimal noise intensity from switch phases which coincides with the one derived from the observation of the signal-to-noise ratio or residence times.
Predict-prevent control method for perturbed excitable systems
Marzena Ciszak,Claudio R. Mirasso,Raul Toral,Oscar Calvo
Physics , 2008, DOI: 10.1103/PhysRevE.79.046203
Abstract: We present a control method based on two steps: prediction and prevention. For prediction we use the anticipated synchronization scheme, considering unidirectional coupling between excitable systems in a master-slave configuration. The master is the perturbed system to be controlled, meanwhile the slave is an auxiliary system which is used to predict the master's behavior. We demonstrate theoretically and experimentally that an efficient control may be achieved.
Suppression of deterministic and stochastic extreme desynchronization events using anticipated synchronization
Jordi Zamora-Munt,Claudio R. Mirasso,Raul Toral
Physics , 2013, DOI: 10.1103/PhysRevE.89.012921
Abstract: We numerically show that extreme events induced by parameter mismatches or noise in coupled oscillatory systems can be anticipated and suppressed before they actually occur. We show this in a main system unidirectionally coupled to an auxiliary system subject to a negative delayed feedback. Each system consists of two electronic oscillators coupled in a master-slave configuration. Extreme events are observed in this coupled system as large and sporadic desynchronization events. Under certain conditions, the auxiliary system can predict the dynamics of the main system. We use this to efficiently suppress the extreme events by applying a direct corrective reset to the main system.
Signal integration enhances the dynamic range in neuronal systems
Leonardo L. Gollo,Claudio Mirasso,Víctor M. Eguíluz
Physics , 2012, DOI: 10.1103/PhysRevE.85.040902
Abstract: The dynamic range measures the capacity of a system to discriminate the intensity of an external stimulus. Such an ability is fundamental for living beings to survive: to leverage resources and to avoid danger. Consequently, the larger is the dynamic range, the greater is the probability of survival. We investigate how the integration of different input signals affects the dynamic range, and in general the collective behavior of a network of excitable units. By means of numerical simulations and a mean-field approach, we explore the nonequilibrium phase transition in the presence of integration. We show that the firing rate in random and scale-free networks undergoes a discontinuous phase transition depending on both the integration time and the density of integrator units. Moreover, in the presence of external stimuli, we find that a system of excitable integrator units operating in a bistable regime largely enhances its dynamic range.
Anticipating the dynamics of chaotic maps
Emilio Hernandez-Garcia,Cristina Masoller,Claudio R. Mirasso
Physics , 2001, DOI: 10.1016/S0375-9601(02)00147-0
Abstract: We study the regime of anticipated synchronization in unidirectionally coupled chaotic maps such that the slave map has its own output reinjected after a certain delay. For a class of simple maps, we give analytic conditions for the stability of the synchronized solution, and present results of numerical simulations of coupled 1D Bernoulli-like maps and 2D Baker maps, that agree well with the analytic predictions.
Mechanisms of Zero-Lag Synchronization in Cortical Motifs
Leonardo L. Gollo,Claudio Mirasso,Olaf Sporns,Michael Breakspear
Physics , 2013, DOI: 10.1371/journal.pcbi.1003548
Abstract: Zero-lag synchronization between distant cortical areas has been observed in a diversity of experimental data sets and between many different regions of the brain. Several computational mechanisms have been proposed to account for such isochronous synchronization in the presence of long conduction delays: Of these, the phenomenon of "dynamical relaying" - a mechanism that relies on a specific network motif - has proven to be the most robust with respect to parameter mismatch and system noise. Surprisingly, despite a contrary belief in the community, the common driving motif is an unreliable means of establishing zero-lag synchrony. Although dynamical relaying has been validated in empirical and computational studies, the deeper dynamical mechanisms and comparison to dynamics on other motifs is lacking. By systematically comparing synchronization on a variety of small motifs, we establish that the presence of a single reciprocally connected pair - a "resonance pair" - plays a crucial role in disambiguating those motifs that foster zero-lag synchrony in the presence of conduction delays (such as dynamical relaying) from those that do not (such as the common driving triad). Remarkably, minor structural changes to the common driving motif that incorporate a reciprocal pair recover robust zero-lag synchrony. The findings are observed in computational models of spiking neurons, populations of spiking neurons and neural mass models, and arise whether the oscillatory systems are periodic, chaotic, noise-free or driven by stochastic inputs. The influence of the resonance pair is also robust to parameter mismatch and asymmetrical time delays amongst the elements of the motif. We call this manner of facilitating zero-lag synchrony resonance-induced synchronization, outline the conditions for its occurrence, and propose that it may be a general mechanism to promote zero-lag synchrony in the brain.
Anticipated synchronization in coupled complex Ginzburg-Landau systems
Marzena Ciszak,Catalina Mayol,Claudio R. Mirasso,Raul Toral
Physics , 2014, DOI: 10.1103/PhysRevE.92.032911
Abstract: We study anticipated synchronization in two complex Ginzburg-Landau systems coupled in a master-slave configuration. Master and slave systems are ruled by the same autonomous function, but the slave system receives the injection from the master and is subject to a negative delayed self-feedback loop. We give evidence that the magnitude of the largest anticipation time depends on the dynamical regime where the system operates (defect turbulence, phase turbulence or bichaos) and scales with the linear autocorrelation time of the system. Moreover, we find that the largest anticipation times are obtained for complex-valued coupling constants. We provide analytical conditions for the stability of the anticipated synchronization manifold that are in qualitative agreement with those obtained numerically. Finally, we report on the existence of anticipated synchronization in coupled two-dimensional complex Ginzburg-Landau systems.
Page 1 /7489
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.