What Is the Most Realistic Single-Compartment Model of Spike Initiation?
(A) Voltage traces of 3 models for the same input current: integrate-and-fire (IF), quadratic (QIF) and Hodgkin-Huxley (HH). The models differ mainly in their spiking responses. (B) Relationships between different single-compartment models. The IF model is a phenomenological model of spike initiation, while the HH model is a biophysical model. Other models can be obtained by reduction, i.e., as approximations of one of the above models under specific conditions.