What is a Reflex Pathway?

Mary McMahon
Mary McMahon

A reflex pathway is a type of neural pathway involved in the mediation of a reflex. Reflexes are involuntary reactions that occur in response to stimuli. They often bypass the brain altogether, allowing them to occur very quickly, although the brain receives information about the reflex as it happens. There are a number of different reflex pathways in the body. In patients with certain kinds of neurological disorders, these pathways become disrupted and the patient develops abnormal reflex responses.

When the right spot on the kneecap is tapped, it triggers a reflex.
When the right spot on the kneecap is tapped, it triggers a reflex.

A classic example of a reflex pathway can be seen in the knee. When the right spot on the kneecap is tapped, it triggers a reflex. Signals from the stimulus are transmitted to the spinal cord along the reflex pathway and the spinal cord activates motor neurons, causing the leg to kick out. The patient's brain is not involved in the processing of this information or the signal to kick, although it does receive sensory information to alert it to the fact that the knee was touched and the leg kicked out.

Reflexes are involuntary reactions that occur in response to stimuli, like the way the leg gives an involuntary jerk when the tendon above the kneecap is hit.
Reflexes are involuntary reactions that occur in response to stimuli, like the way the leg gives an involuntary jerk when the tendon above the kneecap is hit.

Avoiding the brain allows reflexes to occur on a hair trigger. The stimuli and response can be so closely linked that people are unaware until the reflex has already happened. Reflexes are designed to provide very specific protections to the body in response to common stimuli. Having to consciously process the stimulus and determine a response would take too long, potentially exposing the body to risks. The reflex pathway is the shortcut.

The brain receives information about a reflex as it happens.
The brain receives information about a reflex as it happens.

When a reflex pathway becomes damaged in some way, as may happen if nerves are severed, compressed, or demyelinated, the reflex is disrupted. A patient may have no reflexes at all, a sluggish reflex, or an abnormal reflex. This can be detected during a routine neurological exam where the patient is exposed to stimuli and the responses are noted. If a patient responds abnormally, additional testing can be used to learn more about the origins of the altered reflex. This information can be used to develop a diagnosis.

Blinking when an object is close to one's eyes is a reflex action.
Blinking when an object is close to one's eyes is a reflex action.

Scientific studies mapping out reflex pathways have been conducted to allow researchers to understand how reflexes work and to learn about the paths the sensory information takes as it travels from and back to the site of the reflex. These studies have also been applied to people with abnormal reflexes to see where the signal goes wrong or is missed. This can be used to help clinicians accurately diagnose patients when they present in a hospital or clinic with unusual reflex responses.

Those with a hypersensitivity to sound often have an abnormal reflex to everyday noises.
Those with a hypersensitivity to sound often have an abnormal reflex to everyday noises.
Abnormal reflex responses may occur as a result of a neurological disorder.
Abnormal reflex responses may occur as a result of a neurological disorder.
Children who have problems with sensory processing may not reflexively move away if they are burned, leading to serious injury.
Children who have problems with sensory processing may not reflexively move away if they are burned, leading to serious injury.
Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a wiseGEEK researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

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Discussion Comments

orangey03

I have a friend who suffered a beating at the hands of several bullies as a child. As a result, he cannot tolerate being held down. This beating damaged him psychologically, but I think it also caused his body to develop a new reflex pathway.

Since he is terrified of having his arms held down, if someone so much as barely touches his arm on the bicep, his muscle and skin twitches. His brain doesn't even have time to process the touch. It's unlike anything I've ever seen! The trauma gave him a new reflex pathway.

StarJo

An example of a reflex pathway in a dog would be the kicking of its leg when you scratch its belly. You can tell that its brain had no time to tell its leg to kick.

Another example is how a dog's ear will flick rapidly when you touch the tiny hairs lining the inside of the ear flap. At first touch, they don't know what has just happened. It takes a few seconds for them to realize that what you are doing to them is annoying and move away.

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