Our 8th Sense: Interoception
How many senses do we have?
If you asked the general public, most would say five. Those five senses are touch, taste, smell, sight, and sound.
What if I told you there were more? Before you go and chastise your grade school teacher for lying to you, advancements in scientific understanding have only recently categorized two other independent senses. These two other senses are Vestibular and Proprioception. Both senses deal with interpreting how we relate to the external world.
The Vestibular sense analyzes overall balance, specifically how the brain and eyes are positioned to the environment. Vestibular senses are headquartered in the inner ear and relay information between the eyes and brain to comprehend the head’s location in space. When you look up and interpret that you are in fact looking up, you can thank your vestibular sense.
The Proprioception sense focuses on how the rest of the body, the extremities and torso, are positioned to the environment. The main housing centers for Proprioception are found in the muscles and joints of the body. The greatest concentration of Proprioceptors are found in the soles of the feet and the upper cervical spine. When you look up, the proprioceptors of the upper cervical spine communicate with the brain to interpret that in fact, you are looking up.
The Vestibular and Proprioceptive systems are independent, but they interplay extensively with each other. Both communicate to the brain the body’s position in space. In the example of looking up, both talk with the brain and each other to convey information to the rest of the body to adapt to the “looking up” position. If this didn’t happen, looking up could mean falling backward onto your butt.
Now in my best infomercial voice, here is where I interject with a: But wait, there’s more! What if I told you there was one more newly discovered sense? This eighth sense is being called Interoception.
Interoception explains the knowledge and status of every tissue cell of the body at every moment. More knowledge of how the body works has led to the ideas that make up Interoception. While Proprioception and Vestibular sense interpret how we relate to the external world, Interoception reveals how we decipher our internal world.
At this point in time, it is more of a theoretical discovery than a scientific discovery because science has yet to quantify it. This does not downgrade the Interoception hypothesis, it only highlights the wonderful complexities of human beings we still don’t understand.
How is it only a theory?
It is known that the seven senses are under the direction of the Nerve System. We can then deduce that the eighth sense is controlled by the Nerve System as well. The major way a nerve transmits information is through what is called a nerve impulse.
A nerve impulse is an electrochemical signal that propagates functional information from nerve cell to nerve cell and from nerve cell to all other tissue cells. For the nerve cell to transmit the functional information, the nerve cell must initiate what is called an action potential. An action potential can travel anywhere from 1 to 268 mph.
The mystery is that the body actually communicates with itself faster than the fastest action potential. The speed at which the message is sent and the speed at which the message is received doesn’t add up.
You would think the received message would be equal to or slower than the sent message due to the delay in transmission. But this is not so. Information is received faster than at which it is sent. Quoting Dr. Rob Sinnot:
“Interneuronal communication is transmitted at a speed for which science has yet to find a conclusive explanation.”
A concept within Chiropractic that can help frame this communication mystery is the Mental Impulse. Please don’t confuse a Mental Impulse with a nerve impulse. A Mental Impulse could be considered a step above a nerve impulse. It is the point at which thought manifests. Referring to The Chiropractic Textbook by Dr. R.W. Stephenson, a Mental Impulse is:
“A unit of mental force for a specific tissue cell, for a specific occasion. A special message to a tissue cell for the present instant...It is not fully understood what mental impulses are. This is no reflection upon Chiropractic, for, engineers and electricians do not know what electricity is. Yet they know its laws and manifestations and are so able to make practical application of this knowledge...Each tissue cell requires specific impulses every moment. Since there are millions of cells it takes millions of impulses for them every moment. There are new ones for every adaptative change. These impulses are only good for the moment for which they are created.”
If there is one major mystery left of human physiology, it is the human mind. It is staggering to think about what we don’t know about the organ we use to think. We only have glimpses (if that) of its processing power.
So much is above and below the surface. This is because not all thoughts are conscious. The majority of our thoughts, over 95 percent, are considered subconscious. Even though the name “subconscious” implies a downgrade from consciousness, the subconscious is definitely not below consciousness in value.
Some people (including myself) consider the subconscious a part of a “non-conscious” realm. I think I’m pretty smart, but I’m not smart enough to know the constant knowledge and status of over 37 trillion tissue cell of the body at every single moment. That is surely beyond my conscious understanding. And if something is beyond my conscious understanding, it should be considered more of a “superconscious” than a “subconscious.” Concepts such as Mental Impulse and Interoception fit into the superconscious category.
A major conduit for a Mental Impulse and Interoception occurs in the brainstem. The brainstem houses nerve tracts that have ties to all other nerve fibers in the brain and body.
One of the jobs of the brainstem is to take in all the thoughts and actions created in the higher brain centers and distribute it out to its required destination in the body. The brainstem also collects all the receptive information coming from the body and delivers it up to the appropriate brain centers for interpretation.
A vertebral subluxation can disrupt the communication route of a Mental Impulse and Interoception. This creates a “brain-body disconnection.” Function and health can falter.
Adjusting a vertebral subluxation corrects the disruption and allows for a better “brain-body connection.” The better the connection, the better the communication. The better the communication, the better the expression of that communication. The communication between the brain and body is always centered around health. And that is something to not only talk about, but be about.
- Jarek Esarco, DC, CACCP
Related Blogs:
The Vestibular System Influence on Eye Movement, Posture and Cardiopulmonary Function
Muscle Control of the Upper Cervical Spine