Enhanced postjunctional I _Na with shifted biophysical properties promotes faster cell–cell transmission and conduction. (A) Top: Activation time for postjunctional, lateral, and prejunctional membranes for each cell for the baseline/polarized (black) and mix/homogeneous-polarized (magenta) distributions. The change in activation time is shown, adjusted to (middle) cell 24 prejunctional membrane and (bottom) cell 25 postjunctional membrane activation times. (B and C) Intracellular potential φ_i (row 1); cleft potential φ_cleft (row 2); prejunctional (solid) and postjunctional (dashed) I_Na (B, green; C, red) and lateral I_Na (B, black; C, blue; row 3); and gap junction current (row 4) are shown as functions of time for (B) baseline/polarized and (C) mix/homogeneous-polarized distributions. Parameters: g_gap = 100 nS, f_Na = 0.7, w = 10 nm.