Brain volume alteration in chronic pain has been studied in many studies. Most of the reviews were reported that the brain volume decrease in chronic pain, although there were some studies reported that the brain volume increased. The alteration mechanism of brain volume was certain unknown, maybe it caused by nerve hyperactivity in the pain pathway, from nociceptor to post-central gyrus. The alteration of substantia grisea volume decreased is interested to know, which it is occurring in the location of the pain pathway of substantia grisea in the brain. This mechanism was one of the bodyâ€™s ways to reduce the pain score, which then it makes the painless.