polyvagal theory, Steve Porges

Question 1

What is the Polyvagal theory?

Answer 1

ThePolyvagal theory(gr. ‘polus’, “‘many’” + ‘vagal’, “‘vagus nerve’”) specifies two functionally distinct branches of thevagus, or tenthcranial nerve. It serves to identify the relationship between visceral experiences and the vagus nerve’sparasympatheticcontrol of the heart, lungs, and digestive tract. The theory was introduced in 1994 by Dr.Stephen Porges, director of the Brain-Body Center at theUniversity of Illinois at Chicago. According to the theory and its subsequent proof,[1]the autonomic nervous system is interconnected with and sensitive to influences that flow from the body toward the brain, calledafferentinfluences. This effect has been observed and demonstrated by adaptive reactivity dependent on theneural circuits’ phylogenical development. It builds on the study of whatCharles Darwinreferred to as the “pneumogastric nerve.” The polyvagal theory claims that humans have physical reactions,[1]such as cardiac and digestive changes, associated with their facial expressions. Porges argues this theory with observations from bothevolutionary biologyand neurology.

The branches of the vagal nerve serve different evolutionarystressresponses in mammals: the more primitive branch elicits immobilization behaviors (e.g., feigning death), whereas the more evolved branch is linked to social communication and self-soothing behaviors. These functions follow aphylogenetichierarchy, where the most primitive systems are activated only when the more evolved functions fail. These neural pathways regulate autonomic state and the expression of emotional and social behavior. Thus, according to this theory, physiological state dictates the range of behavior and psychological experience. Polyvagal theory has many implications for the study of stress, emotion, and social behavior, which has traditionally utilized more peripheral indices of arousal, such as heart rate andcortisollevel. The measurement ofvagal tonein humans has become a novel index of stress vulnerability and reactivity in many studies of populations withaffective disorders, such as children with behavioral problems and those suffering fromborderline personality disorder.

Question 2

Fight flight

Answer 2

The feeling of fight may emerge as a tensing of the muscles, an increase in our heart rate and breathing, a clenching of the jaws, and a rising feeling of anger or rage. Flight may also be activating as well, as the accelerator-like sympathetic branch of the autonomic nervous system is also engaged, but this time we are driven to run rather than to attack. You may have an impulse to bolt, to avoid a topic, to turn your eye gaze away from me. Fight or flight narrows our focus of attention on strategies of attack or routes of escape. This narrowing of attention shuts off the openness of presence as we become filled with biased probabilities or fixed activations. (Siegel)

Question 3

Freeze

Answer 3

With freeze, we do not engage the sympathetic nervous system, but rather the dorsal branch of the brake-like parasympathetic system. Now we’ve activated the slowly responding unmyelinated part of the vagal nerve that slows our heart rate and respiration, drops our blood pressure, and can even move us to faint. This is the “dorsal dive.” The benefit of these responses is to get us to lay flat to keep blood moving to our head—or to look dead in case a predator is about to devour us. Carnivores prefer to eat living prey rather than the possibly decaying carcasses that would make them ill. The dorsal dive can save your life out on the savanna.

Question 4

Social engagement system and self-engagement system

Answer 4

With the sense of danger, we cannot activate what Porges calls the social engagement system. And we don’t access what I’ve called a self-engagement system either (see Siegel, 2007a). Instead of being present with mindfulness, we become removed, alone, and paralyzed. This is how we move from being receptive to being reactive.