Pain is a complex phenomenon. Although historically, there have been many ways of explaining the origin and maintenance of pain, modern theories follow a biopsychosocial model. This means that pain results from an intersection of biological, psychological, and environmental factors. Here at Beacon Physical Therapy, addressing pain, whether it is acute or chronic, is a big part of what we do. Read on as we describe some the more technical aspects of pain. Hopefully, some of this information resonates with you as you balance your own experience of pain – whether it be a stubbed toe, or pain that you experience much more chronically.

While we would never say that pain is “all in your head,” what we know is that the way we think about pain, feel emotions about pain, and have expectations about pain can certainly affect our experience of the pain itself. Gate Control Theory is a trusted and succinct model of pain that was first introduced in 1965 by Drs. Ronald Melzack and Patrick Wall. Gate Control Theory suggests that the spinal cord contains a neurological “gate” that either blocks pain signals, or allows them to continue on to the brain. According to this theory, the experience of pain depends on a complex interplay of two systems, our central nervous system (spinal cord and brain) and our peripheral nervous system (nerves outside of the brain and spinal cord).

When we stub our toe, the pain messages originate in the nerves associated with that damaged tissue, and flow along peripheral nerves to the spinal cord and then up to the brain. However, before the messages reach the brain, they encounter gates in the spinal cord that open or close depending on a number of factors – including instructions coming from our brain!

It’s a complex system, but here are some more technical points. We have afferent nerve fibers that are either small-diameter (pain-transmitting) or large-diameter (touch/pressure/vibration- transmitting), both of which carry information from a stubbed toe to the dorsal horn of our spinal cord. From there, ‘transmission cells’ carry the painful signal to the brain, whereas other cells, called ‘inhibitory interneurons’, disrupt that transmission cell activity. A painful toe stub stimulates primary afferent fibers, with a signal that travels to the brain via transmission cells. Increasing activity of the transmission cells results in increased perception of pain. In contrast, if activity in the transmission cells is reduced, we perceive less pain.

In Gate Control Theory, a closed gate describes when input to transmission cells is blocked, therefore reducing the sensation of pain. An open gate describes when input to transmission cells is permitted, therefore facilitating the sensation of pain. Have you ever rubbed your toe just after a painful stub, and gotten some pain relief? This is an example of how non-painful sensations can override and reduce painful sensations. When you are rubbing that site, you are essentially activating nerves that do not transmit pain signals, which can essentially provide a gate to block signals from pain fibers.

An overly simplistic way of understanding chronic pain, including pain that is not related to a specific injury site, is to consider what would happen if the gates were left open and for some reason, they were having a hard time closing. In certain instances, messages from the brain can actually amplify pain signals at the nerve gate as it moves up the spinal cord. Some examples of factors that can exacerbate the experience of pain are sensory (e.g., inactivity, poor activity pacing). Other factors that have been found to exacerbate pain are cognitive (e.g., focusing on the pain, worrying about it) and emotional (e.g., stress, hopelessness). The good news, today’s treatments for pain include ways in which we can address physical experience from all of these angles.

Physical therapy can help you to manage all kinds of pain, whether it is from an injury that just happened, or sensations that you’ve been struggling with for years.

At Beacon Physical Therapy, we support our patients in leading a healthy life and establishing a healthy lifestyle. And remember, if you are having an issue, make an appointment today. We’d love to meet you and get you back to doing what you love.