Acute pain is something we’ve all experienced, whether it’s stubbing a toe or banging your funny bone on a chair. Have you ever wondered why your immediate response to this pain is to start rubbing the area? In this second article of our series on how adjustments work, we are going to explore a fascinating pain paradigm, called the gate theory of pain and relate it to the effectiveness of chiropractic adjustments.
Scientists were interested in why people feel the need to rub painful areas and proposed a theory to explain the phenomenon. That theory was proposed in 1965 and coined “The Gate Theory of Pain.”
To understand this theory, we first have to understand how normal sensation makes its way to the brain. The sensory component of the spinal cord is composed of many different tracts of neurons that come from everywhere in our body and go up to the brain. Basically, we have different types of receptors in our body that sense the outside world. Some receptors are sensitive to heat, some to touch, some to chemicals, and some to light.
You can think of each peripheral sensory neuron as a sensor with a wire to the brain with a few stops along the way. The first neuron starts at the surface of the skin and projects all the way to the entrance of spinal cord. The second neuron projects from that entrance of the spinal cord up to the brain in a region called the thalamus. The third neuron projects from the thalamus to the cortex, the region that causes the person to perceive the stimulus consciously.
All different types of sensation (light touch, pain, crude touch, vibration) have different neurons that are bundled together and run in parallel with similar stops along the way. Think of the electrical impulses of these neurons like cars going from point A to point B on the same road with two stop lights: one in the spinal cord and one in the thalamus (the points where these three neurons connect).
One last essential detail to understand is that different types of sensation (pain and touch) have different speeds of conduction through the neurons. This has to do with different levels of myelination. The fibers that carry proprioception and touch are myelinated whereas the fibers that transmit pain are not, which causes the electrical impulse to move much slower.
So think of it this way, touch is like a Ferrari and pain is like a Toyota Camry. They both are trying to go along the same road with the same stop lights to get to the same destination. But there’s one catch. If the Ferrari (touch) beats the Camry (pain) to the first stop light, it actually is able to turn the light from green to red, stopping the camry (pain) from getting to the brain– AKA “closing the gate”. Here’s a neurological schematic for how this actually works.
When you get adjusted, the deep sensory neurons within the spinal joints are stimulated. This stimulation causes a surge of sensory information up through the road to the brain. This stimulation then triggers a red light for the pain signals that are running in parallel, allowing only the touch and proprioceptive sensory information to get to the brain and keeping the pain from being felt in the brain. This effect, although temporary on its own, becomes extremely powerful when coupled with the proprioceptive surge we discussed previously, making chiropractic adjustments remarkably effective for pain relief.
If you’ve been wondering why adjustments feel like a miracle for pain relief, I hope this article helps explain the details of why that is. If you’ve been struggling with a nagging headache or a sore back, keep this information in mind and consider getting adjusted.
