Double stochastic resonance in neuronal dynamics due to astrocytes

A continuously growing body of evidence indicates that astrocytes, which is the most abundant sub-type of glial cells in the nervous system, not only provide structural and metabolic support to neurons, but also they are essential sentinels and dynamic modulators of neuronal and synaptic functions. However, the potential constructive role of astrocytes in information processing at the neuronal and synaptic level, and especially also in the presence of different noise sources in the neural system, is yet unclear. With this in mind, we here study the phenomenon of stochastic resonance - the enhanced detection of weak signals in the presence of noise - in neuronal dynamics by means of a mathematical model that includes interactions between the neuron and the astrocyte. We show that astrocytes may evoke a second peak in the neuronal detection of weak signals in dependence on the noise intensity, which is the hallmark of double stochastic resonance. We explore in detail the mechanisms underlying this discovery, in particular focusing on the determinants of astrocytic function and their role in the emergence of the second stochastic resonance peak. Our research thus provides fundamental insights into the possible roles of astrocytes in inherently noisy neuronal information processing.