The Gate Control Theory of Pain

The feeling of pain, though undesired, is often a good warning sign and something that should be respected. It can point to something more serious, but less noticeable and should be discussed with a medical professional right away.

Generally speaking, pain is any sensation of discomfort or uneasiness. Few people in this world have gone without knowing pain for one reason or another and there are millions who have known it nearly for extended periods of time. The nerves within the body, which work much like a postal service, are responsible for sending the messages to the brain and then carrying messages away that cause the unwanted feelings. It begins with an impact. Whether it is stubbing a toe on a stair, cutting a finger on the edge of a piece of paper, falling on ice in the driveway, or getting hit by a car, the impact is the thing responsible for the pain.

On impact, the nerve endings in that area of the body come to life. Via neural transmitters those nerves pass the message along the highway known as the central nervous system. The nerves responsible for carrying the message on its way to the brain are called afferent nerves. They are received by the thalamus, the part of the brain responsible for handling pain signals. Once received, new messages are sent to make other areas of the body respond accordingly. A stubbed toe may result in your jumping up and down or yelling in pain, a paper cut will make you draw your hand back, and a slip on the ice might make your hand move to the injury, for instance. These messages are sent via efferent nerves. It all happens in a split second because the body is so well equipped to send, receive, and respond to the messages, thanks to the nervous system.

So, why is it that when you stubbed your toe while in your quiet office, you were absolutely certain, because of the amount of pain, that it was broken (even though it wasn’t), but while making dinner for the kids and cleaning up the mess made by the dog, and answering the ringing phone, stubbing your other toe caused very little discomfort? The answer is not entirely known, but it is believed that the other processes of our brain in the moment can affect how we perceive pain.

This is where the Gate Control Theory comes into play. It is believed that there are inner workings of the nervous system and spinal column that dictate how and if those stimuli are received. The messages, which are passed via the afferent and efferent nerves, must climb the spine and enter through the medulla oblongata, in order to reach the thalamus. Along the way, they encounter projection cells, which are, essentially, the gate door guardians. They determine whether or not the message is allowed to pass. Inhibitory inter neurons reside in the dorsal horn and control the projection cells. When no messages are being sent, the doors stay closed. When the small pain receptors send a message regarding pain, the gate is opened. However, it is in the moments of excessive message sending that things get messy. When too much is happening at once and the brain risks being over-stimulated, the inter neurons step in and ensure that the projection cells do not allow the message to pass. So, if you are already trying to complete three different complex motor tasks in the moment you stubbed your toe, for instance, the message may never be received or only partially transmitted, so the pain would be minimal.

The Gate Control Theory also gives reason why we naturally rub away an injury. Parents will often tell kids to ‘rub it off.’ Abidingly, the child will rub where it hurts. What this does, neurologically, is overwhelms the inter neurons and makes them close down the gate, alleviating some of the pain.