Ca_V2.1, Ca_V2.2, and Ca_V3 contribute to calcium influx at the AIS. A, left, 2PLSM z-stack of a layer 5 pyramidal neuron visualized with Alexa Fluor 594. AIS indicated by bracket. Right, Example linescan of AIS averaged over 20 trials. APs were evoked with somatic current injection (1 nA, 5 ms, 20-ms interstimulus interval). B, left, Representative time-locked control cell. Linescan data displayed as mean ± SE. Baseline, black; post, gray. Right, Representative effects of Ca_V antagonist cocktail on AIS calcium. Baseline, black; cocktail, yellow. C, Representative examples of selective Ca_V antagonists on AIS calcium. Baseline, black; antagonists, other colors. D, Summary of the effects of the Ca_V antagonist cocktail on AIS calcium. *p < 0.05, Mann-Whitney U test. E, Summary of the effects of individual Ca_V antagonists on AIS calcium. Gray bar represents 95% confidence interval of control data. p < 0.05, Kruskal-Wallis with Mann-Whitney U test post hoc.