The “Hidden” Senses
Illustration by Chittka L, Brockmann. Derivative work: M. Komorniczak under CC BY 2.5 licencse
The Vestibular System
The sensors for this system are found in the inner ear right alongside our hearing receptors. The vestibular system tells you about your head and body position relative to the space you are in. It tells you when you’re right-side up, upside down, moving forward/backward/side-to-side, and it even tells you about your speed. Together with the proprioceptive system, the vestibular system helps your brain understand its center which is critical for understanding all other sensation. Think about how well a thermometer would work without a “zero point.” How would you know whether to take a light jacket outside (positive 50 degrees Fahrenheit) or to stay inside at all costs (negative 50 degrees Fahrenheit)? Our brain needs this “zero point” too; otherwise, our brain’s ability to understand the location, quality, or intensity of something we hear, see, or feel on our skin would be compromised. Another uniquely important aspect of the vestibular system is its impact on emotion and relationships. What is one of the earliest and most important relationships a baby has when they are born? Their mother? Their father? Of course those are important, but what about the relationship with gravity? Our relationship with gravity is directly related to how well our vestibular system is functioning. When we have a solid relationship with gravity, we feel secure in our bodies and grow to trust ourselves physically. When we feel physically secure, we grow to feel emotionally secure, and this of course affects our relationships with people. In this light, it’s easy to see how difficulties with the vestibular system can create emotional regulation challenges and impact our social and family lives.
The Proprioceptive System
Sensors for our proprioceptive system are found in muscles and joints throughout the entire body. There are a ton of them! They all work together to tell us about our body positioning and movement relative to ourselves. Knowing just how tightly to squeeze your hand and how hard to turn your arm when opening a jar of peanut butter is all thanks to proprioception. Proprioception also allows you to carry a large box up the stairs without tripping even though you can’t see your feet with every step. Proprioception affects the tiniest of movements and muscles—even the ones you use to control your eyes for reading or crossing the street. When the proprioceptive system isn’t working as expected, life just feels harder. This is true even when we do something seemingly simple such as brushing our teeth, putting on a shirt, or stepping off of a curb. The brain and body have to work harder, which puts more stress on the nervous system and ultimately leaves fewer “brain resources” for higher-level skills such as learning in school, negotiating who’s turn it is, or managing our disappointment when something doesn’t go our way.
Adapted from U.S. Government, Public Domain under Title 17, Chapter 1, Section 105
Illustration by Schappelle under CC BY-SA 4.0 license
The Interoceptive System
Perhaps the lesser known of all of the senses is that of interoception. These sensors are found throughout our entire body, including in our internal organs, bones, and connective tissue. Every time you feel hungry or need to use the bathroom, your interoceptive system is communicating from your body to your brain. The same is true when you get butterflies in your stomach. The signals are sent up to your brain and you have to make meaning of the sensation. “Oh, I have butterflies in my stomach. I think I’m really worried about this test I have to take.” These sensory signals are sent to your brain so you can take action in a way that serves you, whether it’s grabbing an apple, running to the bathroom, or hunkering down for some solid study time. Your interoceptive system is also working every time you have a “gut feeling.” The notion that you should “go with your gut” is supported by science. Your interoceptive system has the ability to inform you about how you are feeling about something before your higher-level cerebral cortex can rationalize, make excuses, or overanalyze. Many of us could practice listening to our interoceptive systems more often; however, for people with sensory processing differences, interoception can be even more difficult because of the way their brain is wired. The good news is, through SI therapy and neuroplasticity, this can change too.