NGC-evoked nociceptive behaviors: I. Effect of nucleus gigantocellularis stimulation

The role of the nucleus gigantocellularis (NGC) in nociception was examined by investigating behavioral responses that are supported by NGC stimulation in rats. Analyses indicated that NGC stimulation will support escape, active avoidance, and increases in behaviors that are thought to reflect fear in rats. A variety of behavior patterns were elicited by NGC stimulation, including gross peripheral motor movements such as walking, circling and rearing, and specific orofacial movements such as eye closure, ear movement, jaw opening and facial muscle contractions. No major differences in avoidance, affect, or escape behaviors were revealed between the various electrode placements, suggesting functional homogeneity within this neural region. The results of this study suggest that NGC stimulation generates several components of nociception, including behavioral arousal, autonomic nervous system-mediated responses, aversive affect, and motor responses.