Analgesia elicited by prefrontal stimulation.

Bipolar stimulating electrodes were placed into the medial prefrontal cortex (PFC) or control sites (occipital or cerebellar cortices) in adult male rats. Subsequently, it was determined that PFC stimulation resulted in a significant elevation of nociceptive response latencies, as tested using hot plate and tail flick techniques. Stimulation in control sites did not produce an increase in these response latencies. Rats receiving PFC stimulation were able to respond normally to various innocuous stimuli. Furthermore, seizures were not observed in these rats. These facts indicated that PFC stimulation did not disorient the animals nor inhibit their voluntary motor activity. The results of this study seem to indicate that the PFC is a site from which stimulus-produced analgesia may be elicited.