How Chronic Pain Hijacks the Nervous System
When pain becomes chronic, it stops acting like an alarm and starts behaving like a faulty circuit. Signals keep firing long after the injury has healed. The brain becomes “hyper-attuned” to danger, interpreting even normal movement as a threat.
Neuroscience research describes this phenomenon as central sensitization. Neuroimaging studies indicate that in people with chronic pain, regions such as the anterior cingulate cortex and insula become hyperactive, effectively amplifying pain signals.
This explains why many patients hear “there’s nothing on your scans”, even though their pain is real and persistent.
Central Sensitization
We often assume that the longer we are in pain, the more that we learn to “get used to it” and go on with our lives. If we look under the hood, this often couldn’t be farther from the truth. Your central nervous system – your brain and spinal cord – can actually learn to be in pain.
This process begins in the spine, where the nerves that sense pain from your muscles and joints attach to the spinal cord. Here, the spinal cord experiences what is called a “nociceptive barrage” – it keeps getting hit over and over again with signals that say, “ouch!” Eventually, the spinal cord begins to act like an amplifier, increasing the volume of incoming pain signals.
One way that this happens is by activating a protein called the NMDA receptor, which increases the response to incoming pain signals. Another way is through the production of nitric oxide – a free radical that can increase the volume of incoming signals. These processes may also be responsible for referred pain, which is pain that originates in one location but is felt elsewhere.
Changes also occur in the brain. For instance, in patients who suffer from chronic pain, the brain’s “picture” of the body can become blurry. This can make it hard to pin down exactly where you feel the pain, leading to hard-to-describe “all-over” pain.
As we saw earlier, chronic pain leads to changes in brain areas related to stress, fear and threat detection. These structures are often referred to as the limbic system. When changes begin to occur here, pain changes from being a simple “ouch” to being experienced as suffering. This can also lead to anxiety, guarding and avoidance of previously painful activities that can last for years or decades after the original injury has healed.
Chronic pain can create a vicious loop. For instance, once the limbic structures are activated, they can change the function of a deep midbrain structure called the periaqueductal gray (PAG). One of the things the PAG does is regulate the fight-or-flight-freeze response through the nervous system. It also has a circuit that connects to the spinal cord, which can amplify the volume of the incoming pain signals that we discussed earlier. It may even trigger neurogenic inflammation in your muscles or joints through a phenomenon known as the dorsal root reflex.
While chronic pain can cause many people to avoid training for apparent reasons, stress and central sensitization can also affect physical performance in unexpected ways. For instance, when your nervous system is in a fight-or-flight state, it causes your muscle spindles – the little organs that tell your body how much your muscle is contracted – to misfire. This can cause muscles to overrespond to changes in load or simply tighten up altogether.
Neurogenic inflammation, which is common in patients with central sensitization, can cause trigger points to form in your muscles. When this happens, some parts of your muscle are contracted, while other parts are relaxed and weak. This leads to uncoordinated movement, rapid fatigue, slow recovery and increases the risk of further injury.
The Bioelectric Body
Your body isn’t just chemical; it’s electrical. Every thought, muscle contraction, or heartbeat is driven by ionic exchange. This is why acupuncture’s effects make sense, even to the most skeptical scientists. By stimulating specific nerve fibers, electro-acupuncture interacts with the body’s bioelectric circuits, modulating signals rather than simply masking them. For instance, a growing body of research on transcutaneous vagus nerve stimulation has shown promising results for “turning down the volume” on the limbic system and the descending pain pathways we discussed earlier.
Multiple studies have shown that acupuncture:
- Increases endorphin and enkephalin levels (your body’s natural painkillers).
- Reduces stress hormones such as cortisol
- Downregulates overactive pain networks in the brain, as demonstrated by functional magnetic resonance imaging (fMRI) studies.
Why This Matters for Real Patients
One of our patients, a competitive runner, attended with persistent hamstring pain. He had undergone imaging, stretching routines, and strength training, but the issue always returned.
Upon assessment, we discovered not just local muscle tightness but a complete breakdown in how his posterior chain was firing. His brain had essentially “forgotten” how to coordinate the glutes and hamstrings.
After a few sessions of neuro-acupuncture and dry needling, combined with movement re-education, the pain resolved.
This was not because we treated the hamstring alone, but because we reset the entire neuromuscular circuit, restoring relief and comfort to our patient.
Another patient presented with crippling swelling and pain two years following a joint replacement. Their symptoms were worse with emotional stress or changes in weather. After several sessions of dry needling to restore muscle firing patterns, combined with vagus nerve stimulation and electro-acupuncture at the spinal levels that supplied the affected joint, the patient was able to return to athletic activities with minimal pain.
The Science of What Neuroimaging Shows Us
Functional MRI and PET scans have demonstrated that acupuncture modulates activity in key regions, including the prefrontal cortex, thalamus, anterior cingulate cortex, and insula. As we mentioned earlier, these areas are part of the descending pain modulatory system, basically the brain’s built-in “pain control” mechanism.
- A review in Frontiers in Neuroscience (2021) found that acupuncture consistently reduces activity in hyperactive pain circuits while increasing connectivity in areas linked to emotional regulation and motor control.
- Studies in Dove Medical Press and PMC confirm that acupuncture not only reduces pain intensity but also improves long-term outcomes compared to standard care, providing solid scientific evidence for its effectiveness.
- For tension-type headaches, research from Clinical Rehabilitation and MDPI shows that even a single session of dry needling can deactivate trigger points and reduce headache frequency.
Why Many Treatments Fail
Traditional rehab often concentrates on the site of pain. But if you’ve been trapped in a pain cycle for months or years, you don’t just have a local injury; you have a brain-body coordination issue. This is why simply stretching, strengthening, or taking painkillers may not suffice.
Acupuncture, when combined with movement retraining and soft tissue therapy, targets both the software (the nervous system) and the hardware (the muscles and joints).
This is why our results tend to last longer: we’re not just reducing pain; we’re teaching the body how to move without activating those old alarm circuits.
A Final Word
If you’re dealing with chronic pain or persistent injuries, it’s not because you’re broken; it’s because your nervous system is stuck in a loop that needs to be recalibrated. Pain is common, but it’s not normal.
At Orthopedic & Sports Acupuncture, we have a distinctive approach to healing. Our mission is to help your body recall its natural healing abilities. We combine modern neuro-acupuncture with dry needling, orthopedic testing, and movement-based rehab to guide your body back to health.