Fig. 3. Activation threshold (V) eliciting the A- (AFRR;  A ) and C-fiber-mediated reflex responses (CFRR;  B ) in the ipsilateral biceps femoris 24 h after spinal nerve ligation (SNL) or sham surgery. Each  bar represents the mean ± SEM of five to seven animals.  Asterisks indicate a significant difference from the respective sham control: ***  P < 0.001. Note the differences in activation threshold (V) for the AFRR and CFRR. Representative electromyographic tracings of the AFRR and CFRR after sham (  C ) and SNL surgery (  D ). Note the differences in both the stimulus (S) and response voltages between nerve-ligated and sham-operated rats, and the presence of the CFRR evoked by threshold stimulation of the AFRR after SNL.