Fig. 6.
Histological verification of cannula placements in the RVM. Distribution of microinjection sites in RVM for the drugs used in experiments with 10 Hz (A–D) or 100 Hz EA (E–H): CTOP (A, E), nor-BNI (B, F) and saline in sham EA-treated rats (C, G) and saline in EA treated rats (D, H). Rats in C and G are the same group of rats. The rostral-to-caudal coordinate is with respect to the bregma (Paxinos and Watson, 1998). Sp5, spinal trigeminal nucleus; 7, facial nucleus; Pyr, pyramidal tract.