Fig. 4. Stimulation of the dorsal column and dorsal root attenuated the evoked mechanical responses of wide dynamic range (WDR) neurons in nerve-injured rats. (A ) Peristimulus time histograms (bin size: 0.2 s) show an example of WDR neuronal response to punctate mechanical stimuli (0.6–26.0 g von Frey probe, 5 s) applied to the skin receptive field before and after dorsal column conditioning stimulation (CS). (B ) At 14–16 days postinjury (n = 10), the stimulus-response functions of WDR neuronal response to mechanical stimuli were significantly attenuated 0–15 min after CS at the dorsal column and roots. The total responses of WDR neurons to graded mechanical (C ) and brushing (D ) stimuli were plotted for each group. All data are presented as mean ± SEM unless otherwise specified. *P < 0.05. **P < 0.01 versus prestimulation value. AP = action potential.