Fig. 5
From: Spinal cord stimulation in chronic pain: evidence and theory for mechanisms of action
Supraspinal Mechanisms of Spinal Cord Stimulation. A hallmark of chronic pain, abnormal enhancement of excitatory pathways and a loss of inhibition facilitate nociceptive transmission to sub-threshold stimuli. With SCS, orthodromic activation of supraspinal centers of pain control facilitates antinociception through activation of the DAS, largely through recruitment of the PAG, RVM and LC. Increases in spinal ACh, 5-HT and GABA as well as decreased spinal glutamate with SCS are in part thought to be a result of descending pathway recruitment. ‘Up’ arrows represent increased concentration or activity, whereas ‘down’ arrows represent opposite. ‘Sideways’ arrows represent no change. Acronyms: PAG (Periaqueductal Gray), RVM (Rostral Ventromedial Medulla), LC (Locus Coeruleus), A5 (Noradrenergic Cell Group A5), A7 (Noradrenergic Cell Group A7), DH (Dorsal Horn), DC (Dorsal Column), VLF (Ventrolateral Funiculus), DLF (Dorsolateral Funiculus), RVM ON (RVM On cells projecting from the RVM to the DH), RVM OFF (RVM OFF cells projecting from the RVM to the DH), RVM 5-HT Like (RVM 5-HT Like cells projecting from RVM to DH), cFOS (proto-oncogene), E (Excitatory Interneuron), I (Inhibitory Interneuron), PN (Projection Neuron), Glu (Glutamate), 5-HT (5-hydroxytryptamine), ACh (Acetylcholine), NE (Norepinephrine), GABA (Gamma Aminobutyric Acid)