The effect of input current on canard-induced mixed-mode oscillation in layer II stellate cell

Stellate Cells (SCs) of layer II of medial entorhinal cortex show both subthreshold oscillations (STOs) and mixed-mode oscillations (MMOs) at theta frequencies (8–12 Hz) under increased injection of depolarizing current. The conductance-based model of fully SCs model consists of seven-dimensional nonlinear equations, which imitate many properties of the oscillatory patterns observed in experimental data. Recently, the reduced model of fully SCs model is introduced, which is three-dimensional system with a threshold and reset value for voltage. In this paper, we examine the effects of external current, Iapp, on MMOs pattern in this reduced model. Specifically, by taking advantage of canard phenomenon, we show that only the specific range of values of Iapp can generates the MMOs in this model. Our method provides a geometrical framework to predict the dynamic properties, which can be resulted in MMO patterns.