Comparison of NCVs at different time points after contusion. (a) NCVs under the condition of fixed transmission distance. The red wave represents electrode 1, and the blue wave represents electrode 2). (b) NCVs at days 7, 14, and 28 in the EA, contusion, and control groups. Contusion versus normal, ##P < 0.01; EA versus contusion, ▲▲P < 0.01; EA versus normal, *P < 0.05, **P < 0.01 (n = 5).