Dorsal periaqueductal gray-matter stimulation in humans

Seven patients suffering intractable pain from head and neck cancer (age 48-73, mean 57.5 years) underwent acute stimulation of dorsal periaqueductal gray matter (PAG) with immediate cessation of pain. Two patients received chronic PAG stimulation with relief of pain during stimulation. The effect was not reversed by naloxone and there were no changes in CSF peptides.