Balance between four types of synaptic input for the integrate-and-fire model.

We consider the integrate-and-fire model with AMPA, NMDA, GABA(A)and GABA(B)synaptic inputs, with model parameters based upon experimental data. An analytical approach is presented to determine when a post-synaptic balance between excitation and inhibition can be achieved. Secondly, we compare the model behaviour subject to these four types of input, with its behaviour subject to conventional point process inputs. We conclude that point processes are not a good approximation, even away from exact presynaptic balance. Thirdly, numerical simulations are presented which demonstrate that we can treat NMDA and GABA(B)as DC currents. Finally, we conclude that a balanced input is plausible neither pre-synaptically nor post-synaptically for the model and parameters we employed.