A recent study presented at the American Pain Society annual meeting, shows that if you have chronic pain in one body part, your brain’s reaction to pain in another body part is intensified. The reason is that chronic pain tends to re-wire circuits in the brain region (anterior cingulate cortex or ACC) that regulates how the brain reacts to pain.

Prior studies emphasized “nociception,” which is the sensory nervous system’s response to certain harmful or potentially harmful stimuli. But nociception focuses on the signals from, for example, a burned finger, not on how the brain reacts or deals with the signals once they arrive.

The study arose from clinician’s observation that when patients had chronic back pain they often reported higher than normal paid after surgery in the knee or abdomen. According to Dr. Jing Wang, one of the researchers, “our study results argue that chronic pain causes distortion in how the ACC calculates pain intensity with system-wide consequences.”

In past research, it has been shown that a body part that produces chronic pain can trigger magnified pain when the same part is injured again. But the new study, for the first time, shows that chronic pain tends to increase the reaction to pain-causing stimuli throughout the body. The study authors used rats to study how chronic pain dramatically altered ACC activity. Interestingly, the study results also implied that chronic pain can magnify responses to light (e.g., in migraines) and the ACC can be involved in emotional processes. Thus, anxiety and depression may also amplify the brain’s reaction to painful stimuli.

Focusing on the ACC region of the brain may allow new technologies, like deep brain stimulation and transcranial magnetic stimulation, to deliver electric current to reverse nerve cell signaling patterns that can cause disease.