Understanding Interception and Supporting the Recovery of Trauma Survivors through Yoga: David Emerson
One of the key theoretical underpinnings of our model of Trauma Sensitive Yoga is neuroscience with a particular focus on parts of the brain collectively known as the interoceptive pathways. These are parts of the brain that make visceral sensory experiences available to conscious awareness and research is showing that they are underactive in traumatized people. We use yoga to practice interoception in order to activate the interoceptive pathways. In this brief excerpt from my new book, Trauma-Sensitive Yoga in Therapy, I define interoception in some detail.
One of the most important concepts in Trauma Sensitive Yoga (TSY), and most important but least known words in the English language, is Interoception. In 1906, the Nobel laureate Charles Scott Sherrington, introduced three terms into medical parlance: “proprioception”, “exteroception”, and “interoception”. Of the three, perhaps proprioception, which is basically the awareness of one’s body in relation to external objects, is the most familiar. (Proprioception is why we don’t constantly walk into walls or get into car accidents.) Exteroception refers to awareness of any stimuli coming at us from the outside (sights, sounds, smells etc.). Interoception is our awareness of what is going on within the boundary of our own skin; it is intra-organismic awareness. One researcher who has devoted a good deal of his career to studying interoception is Alan (Bud) Craig (he’s the person who coined the term. “the sentient self” in this context). As a neuroscientist, Craig has developed a picture of interocpetion that is in most ways too complex for our purposes but, basically, he and others have identified nerve fibers that run from all tissues of the body to the brain. These fibers are called “afferent” because their direction is from the viscera (the body) to the brain as opposed to efferent fibers, which run from the Central Nervous System out to the tissues of the body. Of these afferent nerve fibers, Craig says: “Such fibers conduct information regarding all manner of physiological conditions, including mechanical, thermal, chemical, metabolic and hormonal status of skin, muscle, joints, teeth and viscera [internal organs]” (Craig, 2003). Importantly, this afferent information does not have to enter conscious awareness to be considered interoception. It is possible for information from a group of muscle cells, myocytes, (like a certain chemical deficiency), to reach the brain and cause a reaction (like eating protein) without that initial information becoming conscious. With TSY, we are always dealing with conscious processes therefore, for us, we are concerned with feeling dynamics within muscles, as opposed to something that is arguably not directly accessible to consciousness like their specific chemical content. The latter would be considered “metabolic” information and the former “mechanical” according to Craig’s definition but the important thing is that both are interoception.
For another good definition of interoception we can turn to a 2002 review written by Clare J. Fowler in the journal, Brain, of a book called, Visceral Sensory Neuroscience, by Oliver G. Cameron. Ms. Fowler writes: “As originally defined interoception encompassed just visceral sensations but now the term is used to include the physiological condition of the entire body and the ability of visceral afferent information to reach awareness and effect behavior, either directly or indirectly. The system of interoception as a whole constitutes the material me and relates to how we perceive feelings from our bodies that determine our mood, sense of well-being and emotions” (Fowler, 2002). Ms. Fowler’s definition of interoception discerns three components that we will need to deal with: the visceral experience of feeling something in my body (from a muscle contracting or lengthening, to my heart beating, to my stomach grumbling); the motivation to act that the visceral feeling may initiate; and the effect of our visceral experience on our mood and emotions. Again, with TSY, we focus primarily on what Ms. Fowler calls the original definition of interoception, visceral experience.
Excerpted from Trauma-Sensitive Yoga in Therapy, © 2015 David Emerson. Used with permission of the publisher, W. W. Norton & Company, Inc .
David Emerson will be a presenter at the 4th Annual Yoga Service Conference at the Omega Institute, May 14-17, 2015. Clear here for more information and to register.