Researchers have found the key to how memories of pain are stored in the brain especially in nerve cells (neurons) and how they can be erased to ease pain. The central nervous system is known to remember painful experiences that they leave a memory trace of pain. And when there is new sensory input the pain memory trace in the brain magnifies the feeling so that even a gentle touch can be excruciating. Perhaps the best example of a pain memory trace is found with phantom limb pain suggests McGill University neuroscientist Terence Coderre. Patients may have a limb amputated