When safety is present the body can access clarity, growth, and restoration. It can also engage in “spontaneous social engagement behaviors and bodily states”.

Functionally, when the environment is perceived as safe, two important features are expressed. First, the bodily state is regulated in an efficient manner to promote growth and restoration (e.g., visceral homeostasis). This is done through an increase in the influence of myelinated vagal motor pathways on the cardiac pacemaker that slows the heart, inhibits the fight/flight mechanisms of the sympathetic nervous system, dampens the stress response system of the HPA-axis (e.g., cortisol), and reduces inflammation by modulating immune reactions (e.g., cytokines). Second, through the process of evolution, the brainstem nuclei that regulate the myelinated vagus became integrated with the nuclei that regulate the muscles of the face and head. This link results in the bi-directional coupling between spontaneous social engagement behaviors and bodily states. Specifically, the visceral states that promote growth and restoration are linked neuroanatomically and neurophysiologically with the muscles that regulate eye gaze, facial expression, listening, and prosody (see for review (View Highlight)