Figure 1.

Representative action potential (AP) evoked at rheobase depicting AP measurements used in this study. Rheobase was defined as the minimal current required to evoke an AP during an incrementing series of 300–400 ms pulses (see lower traces). AP voltage threshold (dashed red line) was defined as the largest subthreshold depolarization recorded at rheobase (solid black trace) or during (solid red trace) the last subthreshold depolarizing step. AP rise time, AP amplitude, AP fall time, and afterhyperpolarization (AHP) were measured relative to AP threshold. AP duration at half the AP amplitude captured part of the shoulder (note inflection) typically seen in the falling phase of the AP in the tested neurons.