The Stochastic Resonance Phenomenon In The Nervous System Study

Noise is usually considered a nuisance. But in certain nonlinear systems, the presence of noise can actually enhance the response of a system to weak input signals This phenomenon, called stochastic resonance , was frequently reported to be discovered in the nervous system. Here we performed a simulation study of stochastic resonance in neuronal systems.Firstly, stochastic resonance in a single Hodgkin-Huxley neuron was characterized with signal-to-noise ratio and mutual information rate for showing the positive role of noise in subthreshold signal detection. But the ability of a single neuron in delecting subthreshold signal changes as the noise intensity or the amplitude of the subthreshold signal varies. This imposes a limitation on a single neuron in detecting signals with varying amplitude when the background noise intensity is unstable. After studying stochastic resonance in a single neuron, a double layer Hodgkin-Huxley neuronal network was constructed for studying the ability of the network in subthreshold signal detection. The network was investigated and the characteristic of stochastic resonance was observed. Results indicate that the ability of the network in detecting the subthreshold signal changes little when the noise intensity or the amplitude of the subthreshold signal varies within a certain range. Thus, the network does not suffer from, to a certain extent, the limitation in subthreshold signal detection for a single neuron. Intuitively, a neuron will response well to suprathreshold input and adding noise will degrade the neuron's response. In fact, it is not always the situation. Our results show that noise can enhance the response of a neuron to some suprathreshold signals. And stochastic resonance for the suprathreshold signal was observed.