Changes in EPSC parameters have little effect on the ISI distribution.

<p>We investigated how changes to the EPSC parameters affect the ISI distribution in the HH model when the spike rate is kept constant at 9 spikes/s. (<b>A)</b> Increasing the EPSC magnitude (Δ<sub>epsc</sub>) slightly increases the number of short ISIs, shifting the distribution to the left, with a small decrease in the height of the mode. Plotted distributions are for EPSP magnitudes of ~ 1, 2, 3, and 4 mV (darkest to lightest). The changes in EPSPs that result from the changes in <i>k</i><sub>epsc</sub> are plotted on the right. EPSC rates (<i>R</i><sub>epsc</sub> = 2920, 1294, 774 and 526 Hz respectively) were adjusted to achieve a firing rate of 9 spikes/s. <b>(B)</b> Increasing the EPSC time-constant (τ<sub>epsc</sub>) very slightly increases the number of short ISIs, shifting the distribution to the left, with a small decrease in the height of the mode. Plotted distributions are for τ<sub>epsc</sub> = 1.1, 2.2, 3.3, and 4.4 ms (yellow to dark red). The changes in EPSPs that result from the changes in τ<sub>epsc</sub> are plotted on the right. EPSC rates (<i>R</i><sub>epsc</sub> = 2685, 1220, 774, and 567 Hz respectively) were adjusted to achieve a firing rate of 9 spikes/s.</p>