This post is the third in a series of 4 posts about chronic pain. To read the other posts in the series use the links below:
What is chronic pain?, published July 11, 2022
Why we should view pain as a disease, published on July 18, 2022
New approaches to pain management, published on Aug. 1, 2022
At first glance, the pain transmission system seems straight-forward. You experience a sensation upon your body, the nerves within your skin send signals via the central nervous system, alerting your brain to possible risk of injury if not addressed. Your brain begins to send pain signal, encouraging you to pay attention to that area of your body and address any problems. You address the problem, minimizing the risk, and the pain sensation stops
For example, you cut your foot while walking on the beach. The nerve endings in the skin on your foot send the message to your brain that something needs to be addressed. You begin to feel pain in your foot, causing you to investigate why your foot hurts. You see there is a cut, you stop walking, perhaps you put pressure on the cut until it stops bleeding, clean out the wound, apply antibiotic ointment to the area and finally, cover it with a bandage.
But what if the meaning you’ve attached to the wound to your foot changed the pain signal? In the scenario above, your foot may continue
to hurt after you applied the bandage. However, because you know the wound wasn’t deep enough to need stitches, and your past experience with wounds, your brain gives you the narrative “you’re fine” and the pain will subside quickly. You may not even notice the pain unless you begin to pay attention to your foot.
What if, in addition to the scenario above, you had just read an article about a person who was forced to amputate their foot due to a flesh-eating bacteria entering their body through a cut on their foot? To the brain, the narrative is that a cut on the foot is now a possible life-and-death situation, and you perceive the pain significantly different because of what it means to the brain.
Emotions and Pain
This is because the pain center of the brain is comprised of several areas coming online when the brain receives signals from the body indicating possible injury. Our emotional brain (amygdala) begins to interrupt how we should feel about the sensation. In Outcome One, some of the emotions may be indifference or even a slight annoyance that you have to stop what you were doing to address the cut on your foot. In Outcome Two, the emotions are drastically different. You are likely feeling terror, or at least fear, triggering your fight-or-flight response. These different emotional responses will also fuel your decision-making process. All of this begins to lay the foundation for the experience we put away into our memories, which the emotional brain will access for future pain sensations.
Our mood and our sense of safety have a huge role in how we experience pain. One study mentioned in the January 2022 National Geographic issue, looks at how much pain a patient feels can be influenced by the relationship the patient has with their doctor. However, the researchers can’t prove why that happens. Above, Outcome One hints at the answer; if you feel safe and your brain has a narrative that you will be fine, it makes sense that you will feel less pain.
Another study in the same National Geographic issue we discussed in the blog post What is Chronic Pain?, looks at the context surrounding the pain sensation. Volunteers had sections of their forearm exposed to brief heat while listening to sad music. The same volunteers received the exact same heat exposure, but the second time, were listening to happier music. Comparing brain scans of the volunteers showed increased brain activity in the areas associated with pain while they were listening to the sad music. Suggesting that sadness increased pain sensations.