Lesson objective:

In this lesson, we discuss the communication between the brain and the body. This communication requires that we are aware of what, where, and how we feel. The recognition of a physical and emotional state is an act of the body’s interoception. When experiencing trauma or stress, the body’s physical interoception is negatively affected.

Now that we know a bit about the brain’s makeup and structure, it’s important to take a look at how it interacts with and is connected with the rest of the body. After all, the brain is an organ–and thus is interconnected with the rest of the body. 

The brain signals bodily action, but also takes feedback from the body about its current condition. In other words, we look out and we look in. We then use what we learn from outside and inside to make sense of 1) how we are currently doing, and 2) how we could be doing better. 

This back-and-forth feedback is the brain’s way of checking that everything is okay, that all systems are maintaining the equilibrium needed to navigate each day—and—as always, stay alive and safe.

We call this process brain-body communication, and brain-body communication requires that we first and foremost be aware of what, where, and how we are feeling. The awareness of the inner state of your body is called interoception. This is an important concept we will return to over and over again.

In English, the word “interoception” comes from two words—“interior” and “receptive”—literally meaning recognizing feedback from our interior, from our body’s inner world. 

It is easy to understand how the idea of interoception works in the brain and body. Some brief examples:

• Hunger is a signal that you need more food. Sometimes you may recognize hunger as a dull pain in your stomach. Other times, you may realize that you are hungry only when your stomach makes a rumbling sound. Various signs from the body prompt an evaluation. Simply recognizing hunger via physical states like a rumbling stomach or a dull 
• pain is an act of interoception or interoceptive awareness. 
• Thirst is a signal that you are at risk of becoming dehydrated. Sometimes, you may recognize thirst by a sense of dryness in your mouth. In other moments, you may recognize thirst because you feel light-headed or dizzy. Multiple physical signs may indicate the same need. Again, recognition of feeling thirsty is a feat of interoception. 
• Joy can be a signal of many things—that something delighted you, that you were rewarded with something, or that you achieved a goal. Some people feel joy as butterflies in their stomach. Others may feel it as a warmth in their chest, or a lightness in their head. Regardless of where you feel joy, the recognition of how your body feels in response to such moments is an act of interoception that enables you to then experience and deal with the emotion. 

We receive countless signals from the body, and we’re very familiar with a great number of them and what they mean. Much of what we know as “emotions” involve sensations in the body that we notice using our interoceptive awareness–anything from a racing heartbeat, to an ache in our muscles. Interoception is thus a critical starting point for noticing and regulating emotions.

Interoception is greatly affected by stress and trauma–something we will discuss later. However it is important now to note that just as interoception can be affected negatively and without our conscious control due to adverse experiences, we can also increase our interoceptive capacities through simple exercises. More on that later.