At Fit Clinic it is common for us to see clients with chronic pain stemming from a previous injury or accident. Normally the client requires some form of strengthening to return back to the tasks they were previously doing. We often get asked what pain is and why it is occurring, as it is possible clients with ‘higher’ injuries will experience none or little pain, whereas someone with seemingly lesser injuries may be more symptomatic to pain.
Graded increases in physical activity while being guided by the pain response is a way to improve and desensitise this pain and enhance overall recovery.
Why does this sometimes occur?
Pain is the warning system of actual or perceived threat of body tissue damage.
Pain in its simplest form occurs when pain receptors, called nociceptors, are stimulated. These pain receptors send information in the form of an electrical impulse along peripheral nerves to the spinal cord. The electrical impulse will then travel up the spinal cord to the brain. Depending on the situation, the brain receiving and interpreting these impulses may give us the experience of pain.
The pain experience can be modulated (up or down) at every part of the system: the “injured” tissue, the spinal cord, and at many levels in the brain.
For every injury and pain experience there are two components: the process in the tissues, and the process of the pain mechanism.
Homunculus is latin for “little man” and the sensory homunculus is essentially a complete representation of our physical self in our brain.
For example, lets say I pinch your cheeks. This would stimulate neurons in your cheeks that send a message (an electrical impulse) to the spinal cord and then to a special area of the brain. This special area is the part of the brain that is set aside for receiving input from your cheeks. Whether they were pinched, kissed or licked this same little part of your brain will “light up” every time sensory input was detected.
The rest of your physical body is also represented in your brain. That is every physical part of you that can detect sensation has a special area in your brain that will “light up” when stimulated.
Interestingly, bigger areas of your brain are dedicated to receiving input from areas such as the palms of your hands and your tongue. These areas are great at detecting sensation and this is due to these areas having a dense neural field (a lot of neurons to detect sensation). The biggest area of your brain dedicated to a sensation is for seeing and interpreting what you see, this takes up almost ¼ of your brain.
We now know that whilst specific areas of the brain are dominant in certain functions, the whole brain is interconnected and in constant communication. This interconnected web of the brain is called a “neuromatrix”.
A “neurotag” is the specific firing pattern that lights up different brain cell clusters within the neuromatrix. It is trigger and response.
A pain experience uses the same system. Certain triggers can set the pain neurotag to spark across multiple areas in the brain, including (but certainly not limited to) sensation, movement and emotion.
Why some people feel more pain:
The body’s way of protecting us from further harm following an injury is to give us the experience of pain. This is a great mechanism that keeps us safe.
But sometimes our body can turn up the intensity of the pain. It is the brain receiving and interpreting these impulses that gives us the “experience” of pain. In some people the peripheral nerves may be hypersensitive and send electrical impulses to the spinal cord more often than usual. Thereby more danger messages get to the brain.
Furthermore the spinal cord may be so accustomed to receiving these danger messages that it adapts and starts sending more and more danger messages to the brain, even if it only receives a few danger messages from the preripheral nerves.
Finally the brain itself may become so used to giving you the experience of pain that it may give you the sensation of pain even with no danger or damage occurring to your body.
Your brain influencing your pain:
Your cortex or the thinking part of your brain can influence your experience of pain. Thereby what we think can have an influence on what we feel.
Our attitudes, beliefs, values and social environment are further examples of key areas that can have a positive or negative effect on your pain experience.
Since the experience of pain is essentially the activation of a series of connected neurons then it is easy to understand that some thoughts can either “turn up or down the intensity” of the pain experience.