Your Pain is Real: Understanding the Pain System

Struggling with chronic pain can be difficult in itself without the frustration of people questioning your pain. You can have pain without structural damage. It doesn’t make your pain less real; there are just different mechanisms causing your pain. Learn about the pain system and what plays a vital role in your experience of pain. There are also treatments when there is a problem with your pain system.

What is Pain?

Pain is an unpleasant sensory and emotional experience. Pain is a response by the brain to sensations and/or damage to the body. The pain you feel results from interpretations by your brain in response to signals from your body. Pain is a way for your brain to alert you that you may need to stop your actions to prevent further damage or that something is wrong in your body. There are multiple types of pain.

Nociceptive Pain

Nociceptive pain is pain from injury to nociceptors. Nociceptors are receptors found throughout your body that react to chemical, mechanical, and thermal stimuli that might put you in harm’s way. When nociceptors are stimulated enough to reach the pain threshold, signals are sent to the brain to be interpreted so you experience pain. Nociceptors are not pain receptors but receptors that provide information to the brain that can result in pain sensations. An example of nociceptive pain is the pain you feel when you get a paper cut.

Neuropathic Pain

Neuropathic pain can be caused by nerve damage or impairment, such as a pinched nerve, or by injury or a disorder of the peripheral or central nervous system, such as diabetes.

Nociplastic Pain

Nociplastic pain is also known as neuroplastic pain and primary pain. It is pain that is not caused by another condition, such as pain caused by misinterpretations in your pain system. Some conditions of nociplastic pain include fibromyalgia and migraines. Unlike the other types of pain, which are hardware issues, nociplastic pain is a software issue. You need to fix how your brain interprets different signals from your body, not heal some damaged part.

Central Sensitization

Central sensitization is the repetitive stimulation of the nociceptors that causes amplification in nociceptive information, leading to increased sensitization within the central nervous system. It means your pain system has changed to a dysfunctional state where the spinal cord and/or brain have become more pain-sensitive.

In the early stages of sensitization, the output is disproportional to the input, and the sensations are interpreted as more dangerous or damaged than the actual injury. In the late stages of sensitization, there is no input, but the brain continues to receive information about a large area of damage. Your pain system stays active without being stimulated in these late stages. Your pain is real; it just is not representative of what is going on in your body.

Allodynia

Allodynia is a type of central sensitization where you may experience a pain response, sometimes severe, from a sensation that generally does not provoke pain, such as a light touch. It is usually caused by repeated injury or a damaged nociceptor.

Peripheral Sensitization

Peripheral sensitization is when nociceptors have a lower threshold to stimulation than usual, and the pain sensation is enhanced, or where there is amplification within the peripheral nervous system. In this situation, you may have an enhanced sensitivity to pain in one area of your body but not others because the problem is in the peripheral nervous system, not the central nervous system.

When peripheral sensitization represents a form of dysfunctional plasticity of the nociceptor, the nociceptor can change from being simply a detector of noxious stimuli to also being a detector of non-noxious stimuli. This results in low-intensity stimuli from regular activity that don’t usually cause pain, causing a painful sensation. This is referred to as hyperalgesia. Inflammation is one example of a cause that results in the sensitization of nociceptors.

Mixed Pain

You can be experiencing more than one type of pain at once. Often, long-term nociceptive pain or neuropathic pain can be amplified by nociplastic pain. This is referred to as mixed pain. It can mean that you are experiencing much more intense pain than the damage to your body warrants. You can feel much more in control of your pain when you can remove the nociplastic element of your pain. This allows you to make your pain more manageable and predictable, as well as helping you plan for the future and return to activities that you had to give up. The residual pain is also easier to treat after the nociplastic pain has lifted.

The Pain System

Your pain system acts as your body’s alarm system. Most of the time, it is idling consistently. When your nociceptors are activated, they trigger an electrical impulse that travels through your peripheral nerves to your central nervous system and brain. In your brain, these impulses are interpreted and can be modulated (increased or decreased in intensity). There is not one area of the brain responsible for pain but a network of neurons and connections responsible for your perception of pain.

Brain Regions that are Part of the Pain System

Each person activates different areas for the same painful stimulation. Your brain will also activate different regions for the same pain at different times. Activation will differ depending on whether the person feels safe and happy or threatened and sad. The following are the brain areas that may activate during pain experiences.

(You can skip this section if you are not interested in the specifics of the brain’s influence on pain. The next non-brain area section is “Why Do You Experience Pain the Way You Do.”)

Somatosensory Cortex

The somatosensory cortex is found in the parietal lobe. It is involved in processing sensory information and gives the precise localization of the stimulus. It is a primary junction at which body sensations can be amplified into pain or suppressed.

Amygdala

The Amygdala is found in the temporal lobe. It is the processing center for emotions like fear, worry, and anticipation and links your feelings to other brain abilities.

Pain-producing events generate hyperactivity in the Amygdala, which accounts for the emotional-affective aspects of pain. This hyperactivity can interfere with prefrontal processes that can inhibit pain, promoting the persistence of pain-related neuroplasticity in the Amygdala and driving pain behaviour and persistence.

Insula

The insula is involved in information processing, emotional and cognitive components of pain, salience detection, self-awareness, interoception, pain processing, and addiction. It controls autonomic functions by regulating the sympathetic and parasympathetic systems. The insula is involved in the emotional processing of pain, cognitive evaluation of pain, and empathy for pain. It processes painful experiences and drives learning from aversive events. It responds to pain regardless of whether there is overt action but is sensitive to the behavioural relevance of pain.

Thalamus

The thalamus is found in the midbrain. It is the relay center of motor and sensory information, except for smell (relayed directly to the limbic system), from the body to the brain. It is also involved in alertness, sleep, consciousness, learning and memory.

The thalamus is critical to receiving, integrating, and transferring nociceptive information. It also has an important modulatory role. The thalamus converts information about the type, temporal pattern, intensity, and, at least for cutaneous input, topographic localization of pain. It interacts with different brain structures responsible for how stimuli are perceived, the meaning attributed to them, and the emotional dimensions of pain. The thalamus communicates with various structures in the brain to attach meaning to stimuli and is behind the motivational components of pain. The thalamus may hold the key to the awareness of pain and contribute to understanding spontaneous and evoked pain in chronic pain conditions.

Hypothalamus

The hypothalamus acts as your body’s smart control coordinating centre. It keeps your body in a stable state called homeostasis and influences your autonomic nervous system, the main link between your endocrine and nervous systems. It is where your stress response (fight, flight, or freeze) is activated.

The hypothalamus drives both the sympathetic and parasympathetic components of pain. In connection with the brainstem, it may increase or decrease blood pressure and heart rate, depending on the nature of the painful stimuli. It can also inhibit pain transmission and interfere with the reward system, feeding behaviour, and the hypothalamic-pituitary axis (HPA).

Premotor Cortex

The premotor cortex is found in the frontal lobe. It prepares and executes limb movements by coordinating with other parts of the brain to choose the appropriate motions.

Ongoing pain can be associated with preventive measures in signalling dynamics in the premotor cortex and the nervous system’s capability to activate muscles under continual influence of increases in sensory information input to enhance the detection, localization, and reaction to potentially dangerous or noxious stimuli, as well as brain interactions that prevent activation.

Cingulate Cortex

The Cingulate cortex links reward and punishment information, which can elicit emotional responses to behaviour and actions. It is also involved in our ability to focus and concentrate. The cingulate cortex has two main parts that are involved with pain processing: the Anterior Cingulate Cortex (ACC) and the Mid-anterior Cingulate Cortex (MCC). These parts contain premotor fields and have a role in action selection and control.

The Anterior cingulate cortex (ACC) is part of the cingulate cortex. It is fundamental to cognitive processes, including motivation, decision-making, learning, cost-benefit calculation, and conflict and error monitoring.

The mid-anterior cingulate cortex (MCC) is critical in supporting voluntary action to avoid harm. It is also involved in controlling voluntary movement due to nonpainful and painful stimulation and responds to pain when an action is performed.

The MCC works with the insula to generate subjective motivational feelings during pain. There is increased functional connectivity when there is higher self-reported urge to move during pain. Activation in the ACC and MCC for predicted pain depended on whether a meaningful action was performed. The MCC activation has a direct relationship with motor output. Activation in the ACC, MCC, and mid-insula was favourably modulated by whether a predicted stimulus would be painful but not by whether a current stimulus was painful.

Prefrontal Cortex

The prefrontal cortex is found in the frontal lobe. It intelligently regulates our thoughts, actions, and emotions. It is implicated in executive functions, such as planning, decision-making, working memory, personality expression, moderating social behaviour and the orchestration of thoughts and actions in accordance with internal goals. The prefrontal cortex controls certain aspects of speech and language. Executive function relates to the abilities to differentiate between conflicting thoughts, determine good and bad, future consequences of current activities, work towards a defined goal, predict outcomes, expectations based on actions, and social “control.” It supports concrete rule learning, problem-solving, meaning, explanation, interpretation, and memory.

The medial prefrontal cortex’s (mPFC) role in aversive learning and memory makes it a center for the development of mental comorbidities associated with chronic pain. It is involved in the top-down regulation of sensory and affective processes and the inhibition of both sensory and affective pain signals.

It also processes the emotional and cognitive components of pain, which is significantly affected by chronic pain, including gray matter loss. The mPFC receives nociceptive input from the body but also exerts important top-down control of pain sensation. Distraction, positive mood, and anticipation of pain relief can reduce pain by affecting mPFC function.

Cerebellum

The cerebellum helps coordinate and regulate a wide range of functions and processes in the brain and body, including movement, coordination, and cognition. The anticipation of pain was found to activate the same areas as activated during actual pain perception and other areas, possibly involved in preparing for the expected nociceptive stimulus.

Hippocampus

The hippocampus is found in the temporal lobe and plays a significant role in learning and memory. It converts short-term memory into long-term memory, helps with memory retrieval, and is involved in spatial navigation.

It is involved in the development and reoccurring effects of chronic pain. The hippocampus is one of the brain regions that play a crucial role in modulating pain signals; it is activated during pain processing and modification of nociceptive stimuli.

Brainstem

The brainstem relays information from the brain and activates the top-down pathways. It regulates some body functions, such as breathing and heart rate. It also controls balance, coordination, and reflexes. The brainstem is a critical area for nociception, pain processing, and relaying and coordinating signalling between the brain and spinal cord.

Periaqueductal Gray and Rostral Ventromedial Medulla

The brain above controls the periaqueductal gray (PAG) and rostral ventromedial medulla (RVM). They are essential areas of the top-down pain inhibitory pathways where internal opioids and cannabinoids are produced. The other brain areas involved in the top-down pain inhibitory pathways are the anterior cingulate cortex (ACC), Prefrontal cortex, Insula, Spinal cord, and periphery nerves.

Why Do You Experience Pain the Way You Do

You experience pain the way you do because of several factors. First, the sensitivity of different parts of your pain system can increase the chance you’ll experience pain and the pain you feel.

Second, the interpretations of your brain around the signals it receives from your body and senses will impact how you experience pain. Sensations that your brain interprets as dangerous, your brain will activate the areas involved in the suffering and emotional aspects of pain. If your brain interprets the impulses as very dangerous, your brain will make sure you know about it and do something about it through more severe pain.

Lastly, what is going on in your body, mental state, and the present moment can influence how you experience pain. Some examples are whether you are paying attention to the sensation, if you are distracted, if you are having a good or bad day, and other threats or stress within your nervous system.

How Learning Impacts the Pain System

The pain system can work similarly to memory. You need to learn something first. Once you learn it, you can remember it. The more you practice, the more natural it becomes and the better you get at it. The more you think about pain, the stronger the memory of being in pain gets. Eventually, you feel pain stronger and more intensely than before. The connections in your brain learn to present pain more efficiently, effectively, and automatically. When you have been in pain for a long time, the feeling of pain becomes automatic.

The Psychological Influence on Your Pain System

Although all pain is real, psychological factors can strongly influence subjective intensity and each person’s pain threshold.

Influence of Thoughts and Emotions

Thoughts and emotions can make your pain worse. At times, they can be involved with other factors to produce chronic pain without apparent or physical cause.

Catastrophizing thoughts are known for making chronic pain worse because they introduce additional fear to what is going on in your body. Fear doesn’t just increase the threat level in our bodies; it also amplifies danger signals like pain. Because you combine fear and pain, your brain needs to make sure you hear the alarm signals and respond to them.

Influence of Trauma and Neglect

Physical, sexual, or emotional abuse or neglect, either alone or combined with other types of childhood trauma, increases the risk of chronic pain and related disability in adulthood.

 Childhood emotional abuse has been indirectly associated with negative aspects of pain tolerance.

Interpreted Threats in the Nervous System

Our nervous systems interpret threats not just from outside our bodies; they can also be internal. Things that increase the internal intensity of thoughts, such as worries, self-criticism, and pressure, can be interpreted as threats.

Nervous System Dysregulation

Nervous system dysregulation occurs when the sympathetic and parasympathetic systems are imbalanced. This usually manifests as emotional symptoms such as depression, anxiety, irritability, overreactions, and underreactions (shutdown, numbness). It can also manifest in pain and other symptoms, such as fatigue and stomach issues. In nervous system dysregulation, your nervous system often has difficulty returning to a calm state after activation. This can also make us more sensitive to pain reactions. We can also bring more regulation into our nervous system by processing trauma and retraining the brain.

Why We Feel Pain When Nothing is Wrong?

There are times when your pain system does not return to an idling state after a pain experience or injury. This can happen in one out of four people. This sensitization is due to the alarm not calming down all the way. Your body has healed, but your pain system has not returned to normal. In this situation, you will continue to have pain despite the damage being healed.

If your pain system is activated enough, it may become skilled at feeling pain and become easier to set off. The sensitivity of your nervous system is not shown on imaging, and there is a difference between the state of your tissues and a person’s pain. Due to this, you may end up trying different treatments that fail because they don’t address the necessary things.

Why is Your Pain So Bad Compared to the Cause?

The pain system can work similarly to memory. You need to learn something first. But after you learn, you can remember things forever. The more you practice, the better you get at it. The more a person thinks about pain, the stronger that memory of being in pain gets, and the stronger and more intensely they feel the pain. The connections in the brain get stronger, eventually allowing the information to travel automatically. When you have been in pain for ten or more years, feeling pain has become automatic.

When you have nociplastic pain, you need to fix the alarm system. Firefighters won’t be able to solve a malfunctioning fire alarm. You need to fix the pain system. You may also suffer from poor concentration, poor sleep, sensitivity to light, noise and smells, low mood, anxiety, irritability, itchiness, and numbness. These symptoms are signs of nociplastic pain and brain reorganization.

Fixing the Pain System

Pain from central sensitization is nociplastic pain, also known as neuroplastic pain. Your brain is trying to protect you from danger, but it is a false alarm. Since your brain can create false alarms, it can also erase them. The sooner you start, the better the results.

If you do not acknowledge that you have a malfunction of your pain system, then you cannot retrain your pain system. To heal using the brain, we have to learn how to get the medial prefrontal cortex working and to strengthen it, just like we would strengthen a muscle in the body. When it comes to emotional aspects of resilience to pain, a critical approach that helps individuals resist the damaging effects of pain is maintaining high average levels of positive emotion, usually measured as elevations in positive affect. Positive affect has many benefits, such as lowering pain over time and creating more responsiveness in the immune system. Active coping, which is directed actions by an individual to control their own pain and increase function, is connected to resilience to pain. It has been associated with improved physical activity levels, social interaction, and reduced depressive symptoms.

Pain Retraining Therapies and Techniques

Some of the therapies and techniques that can be used to retrain your pain system include:

• Pain Reprocessing Therapy (Somatic Tracking)
• Cognitive Behaviour Therapy
• Mindfulness
• Dialectical Behaviour Therapy
• EMDR
• Emotion Awareness and Expression Therapy
• Polyvagal-informed therapy
• Yoga
• Graded Motor Imagery
• Graded Sensorimotor Retraining

Conclusion

Your pain system is complex and has multiple influences acting on it. When your pain system is dysfunctional, it can lead to a lot of pain and suffering. You can retrain your pain system into a more functional and regulated state.