Fig. 3

Examples of electrically evoked compound action potentials (ECAP) recorded from freely behaving sham SCS-ON (A, C) and SNI SCS-ON (B, D) animals at 2 Hz 200 µs and 50 Hz 200 µs from the first offline observable ECAP (ECAPT) to motor threshold (MT). The stimulation intensity (mA) from ECAPT to MT is indicated by the color bar. Recordings and measurements of ECAPs from (A) 0.067 mA to 0.121 mA (sham SCS-ON; 2 Hz 200 µs), (B) 0.029 mA to 0.051 mA (SNI SCS-ON; 2 Hz 200 µs), (C) 0.060 mA to 0.103 mA (sham SCS-ON; 50 Hz 200 µs), and (D) 0.024 mA to 0.049 mA (SNI SCS-ON; 50 Hz 200 µs). Recordings were captured from channel four (Ch4), the channel closest to the stimulation channel (Ch5, T13) in the antidromic (caudal) direction. The recorded neural signal consisted of a positive P1 peak followed by a negative N1 peak and a second positive P2 peak. The black traces in the insets indicate the different levels of applied stimulus intensity that resulted in the recorded neural signals (only recorded signals at the first offline observable ECAP and MT are illustrated in the inset). The ECAP signal was clearly distinguished from any signal recorded from the stimulation channel. SNI: spared nerve injury