somatic nervous system definition psychology

In Waking the Tiger: Healing Trauma, he explains that emerging from shutdown requires a shudder or shake to discharge suspended fight-or-flight energy. Peter Levine, a longtime friend and colleague of Porges, has studied the shutdown response through animal observations and bodywork with clients. These clients may live in a version of perpetual shutdown. As a result, they feel trapped and their bodies shut down. We may be able to channel this fight-or-flight anxiety into activities such as cleaning the house, raking the leaves or working out at the gym, but these activities will have a different feel than they would if they were done with social engagement biology (think “Whistle While You Work”).įor some trauma survivors, no activity successfully channels their fight-or-flight sensations. If we have unresolved trauma in our past, we may live in a version of perpetual fight-or-flight. Trauma’s effect on nervous system response When we experience our environment as safe, we operate from our social engagement system. This playful spirit characterizes the social engagement system. However, this playful energy has a very different spirit than the intensity of fight-or-flight behaviors. When a dog gives this signal, it cues a level of arousal that can be intense. This signaling often takes the form that we humans hijacked for the downward-facing-dog pose in yoga.

If you go to a dog park, you will see certain dogs that are afraid. Therefore, we can make quicker adjustments between activation and calming, similar to what we can do when we use the reins to control the horse. Ventral vagal release into activity does not involve these sorts of chemical reactions. In addition, once the fight-or-flight chemical reactions have begun, it can take our bodies 10–20 minutes to return to our pre-fight/pre-flight state. Ventral vagal release into activity takes milliseconds, whereas sympathetic activation takes seconds and involves various chemical reactions that are akin to losing the horse’s reins. Likewise, the ventral vagal nerve allows activation in a nuanced way, thus offering a different quality than sympathetic activation. You would continue to pull back on and release the reins in nuanced ways to ensure that the horse maintains an appropriate speed. Picture controlling a horse as you ride it back to the stable. The ventral vagal nerve dampens the body’s regularly active state. This is the branch that serves the social engagement system. The ventral branch of the vagal nerve affects body functioning above the diaphragm. In addition to affecting the heart and lungs, the dorsal branch affects body functioning below the diaphragm and is involved in digestive issues. When the dorsal vagal nerve shuts down the body, it can move us into immobility or dissociation. This reaction can feel like the fatigued muscles and lightheadedness of a bad flu. Shutdown, or freeze-or-faint, occurs through the dorsal branch of the vagus nerve. Polyvagal theory helps us understand that both branches of the vagus nerve calm the body, but they do so in different ways.

Use of our social engagement system, on the other hand, requires a sense of safety. Most counselors are already familiar with the two defense mechanisms triggered by these two parts of the nervous system: sympathetic fight-or-flight and parasympathetic shutdown, sometimes called freeze-or-faint. The two other parts of our nervous system function to help us manage life-threatening situations. Helping our clients shift into use of their social engagement system allows them to become more flexible in their coping styles. The social engagement system helps us navigate relationships. Polyvagal theory identifies a third type of nervous system response that Porges calls the social engagement system, a playful mixture of activation and calming that operates out of unique nerve influence. The parasympathetic part of the autonomic nervous system balances the sympathetic active part, but in much more nuanced ways than we understood before polyvagal theory.īefore polyvagal theory, our nervous system was pictured as a two-part antagonistic system, with more activation signaling less calming and more calming signaling less activation. The vagus nerve serves the parasympathetic nervous system, which is the calming aspect of our nervous system mechanics. Porges’ polyvagal theory developed out of his experiments with the vagus nerve. But Stephen Porges’ polyvagal theory gives counselors a useful picture of the nervous system that can guide us in our efforts to help clients. Although we can imagine bad weather, it is difficult to imagine changing that weather. Picturing brain chemistry can be something like picturing a hurricane.

Somatic nervous system definition psychology