### Extended Data Figure 2-2

Voltage-dependence of activation and inactivation time constants. *A*, The inactivation time constants for *I*_{A} were averaged across all measured voltages. Inactivation time constant was greater in B8 *I*_{A} compared to B51 and B64 (B51 = 0.054_{(0.051, 0.063)} MΩ, B64 = 0.048_{(0.040, 0.055)} MΩ_{,} B8 = 0.18_{(0.17,0.20)} MΩ; *F*_{(2,13)} = 117.4, *p* = 3.8 × 10^{−8}; *post hoc* B51 vs B64, *p* = 0.61; B51 vs B8, *p* = 1.4 × 10^{−7}; B64 vs B8, *p* = 1.19 × 10^{−7}). Plus signs indicate the values used for the models and were 0.035 s for B51 and B64 and 0.14 s for B8. *B*, The inactivation time constants for *I*_{D}. Equation 16 without the second term in the denominator was used to fit these data. Solid lines indicate the time constants for the modeled current. Parameters were: B51, τ_{max} = 3 s, τ_{min} = 0.26 s, h = −14 mV, s = 7; B64, τ_{max} = 5.8 s, τ_{min} = 0.18 s, h = −60 mV, s = 15; B8, τ_{max} = 2 s, τ_{min} = 0.15 s, h = −14 mV, s = 8. *C*, The activation time constants for *I*_{CaL}. Equation 16 was used to fit these data. Solid lines indicate the time constants for the modeled current. Parameters were: B51, τ_{max} = 0.06 s, τ_{min} = 0.002 s, h_{1} = −15 mV, s_{1} = −13, h_{2} = 5, s_{2} = 13; B64, τ_{max} = 0.0088 s, τ_{min} = 0.002 s, h_{1} = 0 mV, s_{1} = −4, h_{2} = 35, s_{2} = 4; B8, τ_{max} = 0.08 s, τ_{min} = 0.002 s, h_{1} = −20.5 mV, s_{1} = −13, h_{2} = 15, s_{2} = 13. *D*, The inactivation time constants for *I*_{CaL} were averaged across all measured voltages. Inactivation time constant was greater in B51 *I*_{CaL} compared to B8 and there was a trend toward being greater than B64 (B51 = 0.22_{(0.17, 0.27)} MΩ, B64 = 0.12_{(0.11, 0.22)} MΩ_{,} B8 = 0.049_{(0.039,0.06)} MΩ; *F*_{(2,14)} = 9.75, *p* = 0.003; *post hoc* B51 vs B64, *p* = 0.22; B51 vs B8, *p* = 0.0024; B64 vs B8, *p* = 0.054). Plus signs indicate the values used for the models and were 0.035 for B8, 0.12 for B51, and 0.14 for B64. *E*, The activation time constants for *I*_{CaR}. Equation 16 was used to fit these data. Solid lines indicate the time constants for the modeled current. Parameters were: B51, τ_{max} = 0.03 s, τ_{min} = 0.001 s, h_{1} = −10 mV, s_{1} = −5.3, h_{2} = 14, s_{2} = 5.6; B64, τ_{max} = 0.02 s, τ_{min} = 0.001 s, h_{1} = 13 mV, s_{1} = −12.7, h_{2} = 25, s_{2} = 13; B8, τ_{max} = 0.076 s, τ_{min} = 0.001 s, h_{1} = −1 mV, s_{1} = −7.2, h_{2} = 23, s_{2} = 7.2. *F*, The inactivation time constants for *I*_{CaR}. Equation 16 without the second term in the denominator was used to fit these data. Solid lines indicate the time constants for the modeled current. Parameters were: B51, τ_{max} = 0.08 s, τ_{min} = 0.038 s, h = 0 mV, s = 5; B64, τ_{max} = 0.036 s, τ_{min} = 0.025 s, h = 0 mV, s = 0.46; B8, τ_{max} = 0.043 s, τ_{min} = 0.025 s, h = 1 mV, s = 6. *G*, The inactivation time constants for *I*_{NaP}. Equation 16 was used to fit these data. Solid lines indicate the time constants for the modeled current. Parameters for B51, B64, and B8 were: τ_{max} = 2.5 s, τ_{min} = 0.25 s, h_{1} = −55 mV, s_{1} = −1.5, h_{2} = −45, s_{2} = 1.5. Download Figure 2-2, TIF file.