Written by: Brooke Preston-Chiropractic Intern at Zen Chiropractic Inc. DBA Zen Healing Center
Most of us are totally different people today than we were five years ago. Why is that? Today, we’re going to dive in and talk about a concept known as neuroplasticity.
What is neuroplasticity?
Neuroplasticity is the idea that the brain and nervous system (neuro) can remodel(plasticity) itself to reflect the experiences we have in our daily lives(5). This means that our nervous system can learn, which is an important concept.
An example of neuroplasticity in our bodies would be our motor (voluntary muscle control and coordination) development. We definitely don’t have the same motor function as when we were babies. We’ve learned to roll over, crawl, sit, stand, walk, and even do more complex things such as type, play sports, write, and play musical instruments.
How does neuroplasticity work?
Think about a set of railroad tracks(5). You’re born with a specific set of railroad tracks. These railroad tracks get messages from Grand Central Station, which in this case refers to your brain. As you learn to do new things- whether they are physical or mental, you lay down new railroad tracks. Some of these tracks get used a lot- they’re heavily developed and polished.
Change happens through a process called long-term potentiation or LTP or long-term depression or LTD. LTP and LTD function similar to a dimmer switch. LTP is when you’re turning up the dimmer switch and LTD is when you’re turning down the dimmer switch. The lights are still on, but in one scenario more light is shining than the other.
What is Long-Term Potentiation (LTP)?
LTP is a pathway that is being stimulated or turned on. Think of it like positive feedback. The more you get, the more you want. So the more a railroad track is used, the more you want to use it and the easier it becomes to use. You polish it, and it becomes well traveled.
You have messengers in your body called neurons that help the brain and body communicate using chemical substances called neurotransmitters. The more a pathway is stimulated, the more neurotransmitter is produced. What does this mean? Think of it in this way: the more a railroad track is used, more cargo can be transported along its path.
If you’re more economically minded, a principle similar to this is the law of supply and demand. The more a consumer (your body) uses something (a pathway) then the more of that product (the neurotransmitter) needs to be produced.
What is Long-Term Depression (LTD)?
LTD is the result of a pathway that isn’t being stimulated and is being muted or turned off. Think of it in the sense “if you don’t use it, you lose it”. The less a railroad track is used, the harder it becomes to access that pathway. It’s still available, but not as readily available. It’s like the rickety old mineshaft railway with old abandoned carts everywhere. It could be restored to its former glory, but it’s going to take a lot of work and practice. These tracks are harder to utilize.
Neuroplasticity and pain.. is it good or bad?
In normal development, the nervous system uses pain as a warning sign. Think about it like using a smoke alarm. Just like that alarm, pain is telling us “Something is wrong, fix it!” This is known as eudynia or “good” pain. This system is used as security against threats like injury, infection, and tumor. In some people, though, this wiring somehow gets mixed up and a system that once worked to protect the body produces long-term effects. The pain tracks are getting an increasing amount of cargo and are being utilized more often. This is known as maldynia or “bad” pain.
What are examples of conditions that may be caused by maldynia?
Some examples of dysfunctional neuroplasticity include when our bodies rewire themselves for pain like was discussed in the last point. Specific examples of conditions include limbically augmented pain syndrome, fibromyalgia, phantom pain, complex regional pain syndrome, visceral (organ) pain, headache, and postsurgical pain.
What does this have to do with chiropractic?
Premise 1: Chronic pain and altered movement
Recent papers have shown that in patients with a history of long-term or recurring neck pain and/or stiffness, episodes of short-term pain with injury may be what induce long-term changes in the brain. Basically, the wrong train track is being laid down, and this disrupts how the brain processes sensation and carries out motor function. If this change in how your body moves is not corrected, long-term altered movement occurs and new train tracks continue to develop and be polished. These new train tracks tell the brain that this is the body’s new normal function and the short term protection that was previously discussed becomes a long-term problem.
The representations of muscles near a site of pain are altered in both the sensory and motor areas of the brain and these areas of the brain are then reorganized to show the new normal. The extent of change is correlated with the level of motor function and/or deficit.
Premise 2: Pain changes your brain
We’ve talked a lot about train tracks in how your body learns, but it turns out that your brain, Grand Central Station, is changed by pain input as well.
One paper concluded that pain can alter activation of the neurons in brain regions associated with the central processing of pain and showed that chronic pain can actually lead to reorganization of the brain(6, 7). This was shown as a reduction in grey matter in patients with chronic low back pain(8). The grey matter is the area that houses the neurons. When we talked about neurons earlier we talked about them as messengers and they were the cargo containers. Fewer cargo containers mean less communication between the brain and body or between different areas of the brain. Unfortunately, the areas that are losing communication are those that decrease and stop pain sensation, so this actually makes the patient more sensitive to pain.
Differences in the “resting” brain have also been documented. This means that brain activity may be different in patients with chronic back pain even when the brain is not processing painful inputs. Significant impairments in memory, language skills, mental flexibility, deficits in cognitive function, and changes in decision-making have been noted in chronic back pain patients.
Chiropractic adjustments have been found to improve how the brain processes sensation and motor information
Research has shown that chiropractic adjustments in the neck can change the processing of sensation and movement within the brain. This contributes to pain relief and restoration of functional ability. The authors conclude that spinal manipulation of dysfunctional joints may modify transmission in neuronal circuits not only at a spinal level but in the brain as well. Imaging was used to draw these conclusions.
Research showed that after a single chiropractic adjustment to dysfunctional neck joints, improved sensory responses in the brain occurred in patients with recurring neck pain and stiffness. Their results indicate an improvement in discrimination and filtering of sensory information from the upper limb for at least 20 minutes after the adjustment.
In addition, the study concludes that these results are not simply due to altered input to the brain from balance, changes in muscle or changes in skin sensors as a result of the chiropractor’s touch or due to movement of the patient’s head because no changes were found after passive neck movement. This implies that results are likely specific to the delivery of the high-velocity, low-amplitude thrust of a chiropractic adjustment. (2,3,4)
(1) Boudreau SA, Farina D, Falla D. The role of motor learning and neuroplasticity in designing rehabilitation approaches for musculoskeletal pain disorders. Manual Ther, 2010:1-5. Epub ahead of print.
(2) Haavik-Taylor H, Murphy B. Cervical spine manipulation alters sensorimotor integration: a somatosensory evoked potential study. Clin Neurophysiol, 2007;118:391-402.
(3) Haavik-Taylor H, Murphy B. Altered sensorimotor integration with cervical spine manipulation. JMPT, 2008;31:115-26.
(4) Haavik-Taylor H, Murphy B. ACC-RAC Award Winning Paper. Altered central integration of dual somatosensory input after cervical spine manipulation. JMPT, 2010;33:178-88.
(5) Ray, AA. Treatment of Chronic Pain by Integrative Approaches: The American Academy of Pain Medicine Textbook on Patient Management. Springer. 2015. P52 ISBN: 978-1-4939-1820-1
(6) Strutton P, Theodorou S, Catley M, et al. Corticospinal excitability in patients with chronic low back pain. J Spinal Disord Tech, 2005;18:420-4.
(7) Tsao H, Galea M, Hodges P, et al. Driving plasticity in the motor cortex in recurrent low back pain. Eur J Pain, 2010;14:832-9.
(8) Wand BM, et al. Cortical changes in chronic low back pain: current state of the art and implications for clinical practice. Manual Therapy, 2010:1-6. Epub ahead of print.