Before revision:  We provide details of the model, as well as a representative numerical example , and discuss an intrinsic interconnection between active and passive customers in the underlying stochastic process.
After revision:  We provide details of the queueing theory and neuronal models and discuss a relationship between reflecting SDEs and a model of queueing theory via a limit theorem. Furthermore, we present several representative numerical examples , and discuss an intrinsic interconnection between active and passive customers in the underlying stochastic process.