Mechanisms behind initial bursts and regular spiking.

<p>All panels show responses to a 70 pA depolarizing current injections. As a reference, the responses in (<b>A</b>) use the original parameters for P1 and P2, and are the same as in <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1002160#pcbi-1002160-g004" target="_blank">Figure 4</a>. In P2, the initial burst and the regular spiking are separated by a pronounced afterhyperpolarization (<b>A1</b>), while in P1 the transition between the initial burst and the regular spiking is more gradual (<b>A2</b>). These characteristics were interchanged between P1 and P2 when <i>g_AHP</i> was interchanged (i.e., multiplied/divided by a factor 2.03 in P1/P2) between the two parameterizations (<b>B</b>). Initial bursts were eliminated when <i>g_CaT</i> was set to zero (<b>C</b>), and became stronger when <i>g_CaT</i> was increased by a factor 2 (<b>D</b>). Increasing <i>g_AHP</i> and <i>g_CaT</i> by a factor 2 gave rise to periodic bursting in both neurons (<b>E</b>). The scale bar applies to all panels. When conductance values were changed, the resting potential was kept at the original level by small compensatory current injections.