[NEST Users] I want to know the derivative equation of iaf_psc_alpha neuron model to design some algorithms for neural network

Hi everyone, I have a very big problem now again for the iaf neuron(such as iaf_psc_alpha), which is I don't know know differential equation for the neuron model, so I can't get the derivative of voltage about some other variable, such as derivative of voltage versus synapse weight. The point is I do need to know the derivative equation of iaf_psc_alpha neuron model to design some algorithm for neural network. For the paper mentioned below, I still can't figure out the exact derivative equation of voltage or voltage state equation. https://link.springer.com/article/10.1007/s004220050570 By the way, At last meeting, I wanted to ask that but my device had trouble when host asked, so awkward. Hope for your answer. Thank you. Enguang