Activation:	G=1/(1+exp[−0.03937*z*(V−V½)]), in which G is conductance, z is the apparent gating charge, V is the potential of the given pulse and V− is the potential for half-maximal activation.
Inactivation:	I=1/(1+exp[(V−V½)/a]), in which I is equal to the test-pulse current amplitude, V is the potential of the conditioning pulse, V½ is the voltage for half-maximal inactivation and a is the slope factor.
Recovery:	I =1−A·exp(−t/τ)−c, in which A is the fraction of current that recovered with the time constant τ, t is the recovery time and c is the fraction of current that did not recover.
Use-Dependent inactivation:	I=A1*exp(−t/τ1)+A2*exp(−t/τ2)+c; double exponential, in which A1 and A2 are the relative fractions of current that decayed with the time constants τ, and τ2, t is the decay time and c is the remaining current. I=A1*exp(−t/τ1)+A2*exp(−t/τ2)+A3*exp(−t/τ3); triple exponential, in which A1, A2 and A3 are the relative fractions of current that decayed with the time constants τ1, τ2 and τ3, and t is the decay time.