Researchers have demonstrated that conditioned pain modulation (CPM), a measure of the brain‘s ability to regulate pain, decreases activity in the human spinal cord as visible via functional magnetic resonance imaging (fMRI).
“This study confirmed our hypothesis that CPM results in significant reductions in spinal dorsal horn activity in humans,†said lead study author Ian Mackey, of Stanford University in Palo Alto, Calif. The results were presented in a scientific poster today at the American Academy of Pain Medicine’s 30th Annual Meeting.
Recent research has focused on the brain’s powerful ability to regulate the pain experience, a capacity that is reduced in patients with chronic pain. CPM is one way scientific investigators test endogenous analgesia in this setting. CPM is when pain produced by a (conditioning) stimulus at one body part results in reduced pain perception to a second pain-producing (test) stimulus at a distant body part. The CPM effect is the reduced pain rating of the second or test stimulus, also described as “pain inhibiting pain.â€
Low CPM efficiency, which indicates a low capacity to inhibit pain through the body’s endogenous systems, has been associated with the development of various pain syndromes, including irritable bowel syndrome, temporomandibular disorders, fibromyalgia and tension type headache and – in some reports – with neuropathic pain (Yarnitsky, Curr Opin Anaesthesiol 2010;23(5):611-5).