Abstract: Synapses represent a fundamental unit of information transfer during cognition. They accomplish this by a process called presynaptic vesicle exocytosis, which can occur either spontaneously or by stimulation (called evoked release). It has been well established that evoked release is probabilistic in nature, but it has been less clear what mechanisms mediate spontaneous exocytosis. Understanding spontaneous exocytosis is important because it is an essential maintenance mechanism for synaptic connections and memory formation. In this talk I will introduce the complex set of biological parameters and fundamental molecular mechanics of how synapses communicate in a probabilistic manner. I will then present our recent theoretical and experimental work developing a conceptual framework, based on entropic force, that shows how presynapses regulate spontaneous exocytosis using the same complex set of biological parameters. I will discuss how this spontaneous exocytosis process is regulated during what is called synaptic plasticity, which is a fundamental mechanism of memory formation