$d V d time = − (i_Ca + i_K + i_s1 + i_s2 + i_L) / Cm$

$i_Ca = g_Ca m_infinity (V − V_Ca)$

$m_infinity = 1.0 / (1.0 + e (-22.0 − V) / 7.5)$

$i_K = g_K n (V − V_K)$

$d n d time = (n_infinity − n) / tau_n n_infinity = 1.0 / (1.0 + e (-9.0 − V) / 10.0) tau_n = 8.3 / (1.0 + e (V + 9.0) / 10.0)$

$i_s1 = g_s1 s1 (V − V_K)$

$d s1 d time = (s1_infinity − s1) / tau_s1 s1_infinity = 1.0 / (1.0 + e (-40.0 − V) / 0.5)$

$i_s2 = g_s2 s2 (V − V_K)$

$d s2 d time = (s2_infinity − s2) / tau_s2 s2_infinity = 1.0 / (1.0 + e (-42.0 − V) / 0.4)$

$i_L = g_L (V − V_L)$