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 s ubject to conventional point process inputs. We conclude that point process es 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. (C) 2001 Academic Press.