Stochastic response

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Stochastic resonance describes a phenomenon that can occur in a noisy nonlinear system with certain properties when it is excited by a periodic signal . The term was coined in 1981 by Italian and Belgian physicists to explain the periodic recurrence of ice ages. Stochastic resonance is of technical importance for the amplification or detection of periodic signals that are very weak compared to the (normally disruptive) system noise. Comparable to the phenomenon of resonance , in which there is a best excitation frequency , in the case of stochastic resonance there is an intensity of the noise at which the signal can be best detected. Paradoxically, this intensity is apparently not zero.

A simple example of stochastic resonance is a time signal

example

The non-linear system in the neuronally motivated example shown in the adjacent figure is the threshold (blue) which, when exceeded, triggers an action potential . The signal (red) is always below the threshold. But if noise is added to the signal (black), the threshold is occasionally exceeded. If the threshold is exceeded, the blue lines at the bottom of the screen indicate. The probability of this is higher in the maxima of the noisy signal than in the minima. If the noise intensity is very low, the threshold is never exceeded, but if it is very high, the signal is no longer reproduced well in the dense sequence of action potentials. A medium noise intensity is optimal for mapping the signal after the non-linear stage.

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