Analysis of a Stochastic Noisy Communication Channel in a Tripartite Synapse with Astrocytes

Synaptic plasticity is the ability of synapses to change their strength in response to activity. This process is reputated to underlie learning and memory formation in the brain. Synaptic plasticity can occur through various mechanisms, including long-term potentiation. Astrocyte is one of the actors in regulating synaptic plasticity by releasing signaling molecules which can enhance or inhibit synaptic strength. Indeed the concept of tripartite synapse refers to the functional integration of the presynaptic membrane, postsynaptic membrane, and their interactions with the surrounding astrocytes considered as three synaptic components contributing to lead to synaptic activity. In this paper we investigate on the impact of different types of noise in the context of tripartite synapses. In particular we estimate the effect of axonal noise, as well as calcium influx and astrocyte calcium concentration variation, showing that these noise sources significantly impact on both mutual information and channel opening probability as compared to the case when no noise is assumed.