Role of calcium and noise in the persistent activity of an isolated   neuron
  The activity of an isolated and auto-connected neuron is studied using Hodgkin--Huxley and Integrate-and-Fire frameworks. Main ingredients of the modeling are the auto-stimulating autaptic current observed in experiments, with a spontaneous synaptic liberation noise and a calcium--dependent negative feedback mechanism. The distributions of inter-spikes intervals and burst durations are analytically calculated, and show a good agreement with experimental data. 
Simona Cocco