Interactions between nucleus centrum medianum and gigantocellular nociceptive neurons

Cells in nucleus reticularis gigantocellularis (NGC) and nucleus centrum medianum (CM) are known to respond to tooth pulp stimulation, which is a nociceptive trigeminal stimulus. We examined the effect of stimulation of CM on this class of neurons in NGC. Thirty-nine percent of the 57 neurons tested were antidromically activated by stimulation of the ipsilateral CM, while 28% of the 40 neurons tested were antidromically activated from the contralateral CM. In addition, the spontaneous activity of seven NGC neurons was altered by stimulation of the ipsilateral CM, while five cells were affected by stimulation of the contralateral CM. These data suggest a complex and reciprocal interaction between neurons in NGC and CM.