The TENS therapy is based on the natural, endogenous system of transmitting information. Both positive and negative sensations (such as pain) pass via the same nervous system to the brain. TENS uses the fact that pleasurable sensations run on faster nerve pathways as negative. Thus, if the gentle electrical impulses, which the TENS therapy uses, arrive in the spinal cord, is for the pain information already no more space; it can be processed by the brain no longer. In addition, TENS causes that body's endorphins, called endorphins are released. These two factors cause the feeling of pain is often significantly alleviated or disappears altogether.