Biomedical subjects

J M R Parrondo

Publications and source records attributed to J M R Parrondo.

3 recordsLinked to original sources

PubMed2005

System-size resonance in a binary attractor neural network.

System size resonance (SSR) is a phenomenon in which the response of a system is optimal for a certain finite size, but poorer as the size goes to zero or infinity. In order to show SSR effects in binary attractor neural networks, we study the response of a network, in the ferromagnetic phase, to an external, time-dependent stimulus. Under the presence of such a stimulus, the network shows SSR, as is demonstrated by the measure of the signal amplification both analytically and by simulation.

Action Potentials↗

PubMed2002

Pattern formation induced by nonequilibrium global alternation of dynamics.

We recently proposed a mechanism for pattern formation based on the alternation of two dynamics, neither of which exhibits patterns. Here we analyze the mechanism in detail, showing by means of numerical simulations and theoretical calculations how the nonequilibrium process of switching between dynamics, either randomly or periodically, may induce both stationary and oscillatory spatial structures. Our theoretical analysis by means of mode amplitude equations shows that all features of the model can be understood in terms of the nonlinear interactions of a small number of Fourier modes.

Journal Article↗

PubMed2001

Stationary and oscillatory spatial patterns induced by global periodic switching.

We propose a new mechanism for pattern formation based on the global alternation of two dynamics, neither of which exhibits patterns. When driven by either one of the separate dynamics, the system goes to a spatially homogeneous state associated with that dynamics. However, when the two dynamics are globally alternated sufficiently rapidly, the system exhibits stationary spatial patterns. Somewhat slower switching leads to oscillatory patterns. We support our findings by numerical simulations and discuss the results in terms of the symmetries of the system and the ratio of two relevant characteristic times, the switching period and the relaxation time to a homogeneous state in each separate dynamics.

Journal Article↗