Chronic pain may rewire the brain
Chronic pain may alter certain brain functions, which can result in fatigue and decreased levels of motivation, according to new research.
Scientists at Stanford University used mice, which they divided into three groups--one group had injuries to their sciatic nerves (located in the back of the leg), one group had inflammation in their paws, and the third group had no injuries.
At the beginning of the study, the researchers gave the mice a chocolate-flavored treat if they poked their noses into a small hole. The task became progressively difficult, as the mice were required to do an increasing number of nose pokes for the treat. The test was then repeated one week later.
The results showed that as the task became more and more difficult, the injured mice began to perform more and more poorly, when compared to the mice with no injuries. The results were consistent even after the injured mice were given painkillers.
The researchers were able to trace the decreased motivation in the injured mice to a chemical in the brain, called galanin, which resulted in the part of the brain associated with pain and motivation not firing properly. When they deactivated the chemical and re-administered the test, the injured mice performed as well as the uninjured mice.
The findings of the study, published in the journal Science, may guide future research on chronic pain and lead to new potential treatments, researchers said.