A lumped model of the septohippocampal circuit consists of three interconnected populations of cells. Main population of pyramidal cells (red) receives external inputs and excitatory and inhibitory feedback from  two local populations of interneurons (blue). The model includes some of the main intrinsic membrane properties of the pyramidal cells, namely calcium dependent, potassium current (yellow). Depolarizing afterpotential (DAP) and after hyperpolarization (AHP) are essential phenomena in the model that produce epileptiform signals.

The output signal shows average membrane potential in the pyramidal cells population. Time scale 10 s. Short tetanus input (arrows) induces transition in the signal from normal theta (8 Hz)  to epileptiform (3 Hz, high amplitude) activity.