According to this article, a new study presented at the American Pain Society meeting shows that chronic pain in one body part may distort the intensity of how a key region of the brain perceives pain anywhere else.
The new study is the first to show that chronic pain in one locale causes a greater reaction to pain throughout the body. The researchers found that chronic pain in one limb in rats increased the aversive response to acute pain stimuli in the opposite limb.
Their findings support the theory that chronic pain rewires circuits in the brain to increase “aversion,” the amount of attention paid to, and alarm felt about, any given pain signal. Most previous studies have focused on nociception, the intensity of incoming sensory signals instead of what the brain does once the signal is received.