Enhance Signal Detection in Auto-Associative CA3 Pyramidal Neuron Model Using Electric Field Noise

Abstract

Stochastic Resonance (SR) is a nonlinear system phenomenon which plays a significant role in the detection of subthreshold signals. In this study, we utilize a two-cell coupled oscillator model to represent the abundant auto-associative connections between pyramidal neurons in the CA3 region of the hippocampus. It is an appropriate model for this investigation since some CA3 neurons had been shown to exhibit oscillatory behaviors. This type of neuronal connection is of particular interest because it has the ability to generate a wide range of possible neurodynamics. Unlike other similar studies, each oscillator unit is equipped with four input portals representing different modes of coupling and stimulation. Entrainment properties of the oscillators are governed by the intrinsic and coupling properties, which allow for different network configurations, neuronal classifications and stimulation protocol. Here, we hypothesize that subthreshold harmonic signals with frequencies associated with higher cognitive functions, learning and memory consolidation can be enhanced with an appropriate level of noise. Appropriate coupling conditions of the model were obtained to create a high complexity chaotic system which was quantified using complexity measures. The amplitude of the subthreshold harmonic signal was found experimentally. Harmonic signals at various frequencies were superimposed by Gaussian noise and were applied to the inputs pathway associated with electric field coupling. The power spectrum of the output signals was obtained and was compared with the zero noise baseline power. It was observed that the power spectrum of 40 Hz and 13 Hz frequency component (which are also associated with learning and memory) exhibited the maximum power exceeding that of the noiseless control only at some specific and narrow noise intensities.KeywordsStochastic resonanceCA3 hippocampuscoupling neuronnonlinearchaotic behavior