Some small IB4− TG neurons exhibit sAPs in the absence of TRESK. A, Representative traces of WT and TRESK KO small IB4− TG neurons under current clamp recording without current injections. Top, Neurons exhibiting no DSF or sAPs; middle, neurons with DSF but without sAP; bottom, a KO neuron with sAPs. Note that every DSF results in an AP. B, The percentage of neurons with sAPs in all TG neurons and in small IB4− TG neurons from WT and TRESK KO mice, respectively. ***p < 0.001, Fisher’s exact test between the corresponding WT and KO groups. The dashed line indicates 0%. C, The AP threshold of WT and KO small IB4− TG neurons without sAPs (w/o sAPs; same neurons as in Fig. 3B) as well as KO TG neurons with sAPs (w sAPs; n = 11). **p < 0.01, one-way ANOVA with post hoc Bonferroni test.