Modulation of dorsal horn neuronal activity by spinal cord stimulation in a rat model of neuropathy: The role of the dorsal funicles

We recorded the spike activity from spinal neurons In rats with a model of neuropathy after ligation of then. ishiadicus. A significantly increased frequency of background discharges and responsiveness to nonnoxious stimuli were observed in dorsal horn wide-dynamic range (convergent) neurons in a group of allodynic rats, as compared with non-allodynic and intact rats. Spinal cord stimulation (SCS) Induced a significant depression of both the principal responses and afterdischarges in allodynic rats. The frequency of background discharges was markedly decreased in approximately one third of the neurons. These effects outlasted SCS by about 10 rain. The moderating effect of SCS is considered a result of activation of distinctly different and complementary mechanisms: segmental and transsupraspinal. The former appears to be the most important in allodynic animals.