Abstract:

Descending spinal field potentials (dSFP) evoked by C₂ stimulation in anesthetized and immobilized rats were recorded from the lumbar enlargement with silver-ball electrode and compared with the segmental spinal field potentials (sSFP) induced by peroneai nerve stimulation. Similar to waves A, N, and P of the sS FP, the dS FP consisted of a raPid spike (A’) , a slow nagative (N’) , and a slow positive (P’) waves. The active area of waves N’ and p’was 2-3 times larger than that of N and p waves’.The longitudinal distribution of dSFP was mush wider than the sSFPs’. In the middle of wave P’ there was a valley, which disappeared after C₁ transection.The dS FP vanished following cutting the dorsal columns whereas increased in size after bilateral transection of the dorsolatoral funiculi. The results indicate that waves A’, N’, and P’ of dSFP seem to possess the same intrasPinal origin as that of waves A, N, and P of the sS FP while the cervical stimulation descending the dorsal cofumns may activate more components in the spinal cord in comparison with the segmensal volleys.