Stochastic resonance in feedforward-loop neuronal network motifs in astrocyte field

Elucidating the underlying dynamical properties of neuronal network motifs, statistically significant patterns of interconnections, is essential to understand the dynamics of the whole networks. Besides, the brain is intrinsically noisy. Various noise-induced dynamical behaviors, in particular, the stochastic resonance (SR), have been found in both neuronal systems and neuronal network motifs. However, the effect of astrocytes, active partners in neuronal signal processing, has not yet received much attention. In this paper, we study the effect of astrocytes on the stochastic behaviors of the typical triple-neuron feedforward-loop (FFL) neuronal network motifs. The neurons are described by the Hodgkin-Huxley model, while the astrocytes are modeled by extending the Li-Rinzel model to a two-dimensional field with the effect of diffusion. The mutual neuron-astrocyte interactions are established correspondingly. Simulation results indicate that the stochastic behaviors of the FFL motifs show bell-shaped dependence on the intensities of both noise and astrocyte-neuron coupling. Moreover, in the presence of astrocytes, the performance of the FFL motifs on weak signal transmission in both noisy and noise-free environments can be significantly improved. From this point of view, the astrocytes can be regarded as a possible internal source of "noise", which assist the neurons in signal processing. (C) 2013 Elsevier Ltd. All rights reserved.