Your Brain Decides Whether You Are in Pain or Not

Everyone has experienced pain in one form or another in one part of their body or another over the course of their lives. Sometimes the pain lasts for just a few seconds, sometimes a few minutes, sometimes hours or days, and once in a while, pain becomes chronic, continuing for months or years. What is it about pain that can make uncomfortable feelings last for just a few seconds with a weird misfiring in the nervous system, or last for decades with chronic syndromes such as fibromyalgia, a serious condition that causes widespread pain over many regions of the body?

Whenever a person has a painful feeling, it is best not to ignore it. The brain evaluates various inputs from the skin, muscles, and other tissues when determining whether the body is in danger or not. Sometimes the pain message is immediate and clear, such as putting a finger in boiling water. But other times, the condition of the tissues may not clearly indicate pain one way or another, so it is the brain that decides whether the tissues are in danger and whether to send a message to the body to get the endangered finger or limb out of the way. Ignoring such messages when they first occur can lead to the pain continuing for longer periods of time or causing more tissue damage.

The brain constructs its pain feelings and messages through various inputs. Many times, the feeling comes straight from the tissues themselves, such as when a person gets a paper cut and has an immediate sensation of burning and discomfort. But other times, the brain does not sense that the tissues are in danger, such as when a person is playing sports and sustains a cut or scrape but does not feel it until he or she notices that the injury has caused bleeding. Seeing the injury can help the brain construct the pain feeling from the visual input. So pain can be considered a conscious experience that is constructed through unconscious processes whereby the brain decides -- based on various sensory inputs -- whether or not to construct the pain feelings.

In terms of pain that lasts for long periods of time, the brain keeps constructing these pain messages regardless of the quality of the tissues. The brain perceives a part of the body to be in danger, so it creates pain. In fact, messages between the nerves and the brain can travel in both directions. A paper cut may cause a message to go from the site of injury to the brain that something is wrong, and then the brain sends back the pain feeling based on the inputs. But the brain can also send a pain feeling to the tissues without the tissues originally sending a clear indication of the condition of the tissues. In fact, the brain and nerves can become more sensitized with chronic pain and send the messages more efficiently and more often.

Everyone suffers from injury and tissue damage at one time or another during their lives. But whether or not that damage is sufficient to cause painful feelings is evaluated by the brain, which examines whether or not particular damage puts the body in danger. And it is not just the injury itself that the brain uses to evaluate this level of danger, as it takes into account various sensory inputs, including the visual system, in order to create the pain experience. This is both why elite athletes continue playing important games with fractures, and why chronic pain may continue long after an injury has healed.