Dr. Stephen Porges propose an intriguing link between feeling safe and making changes. According to his theory, the brain has three states in relation to safety: green, yellow and red.
When people are feeling safe, they would be in the green state where learning, connection and healthy interactions with the environment take place. Normal people move easily from green to yellow and back to green.
The vagus nerve is responsible for both: relaxation and alert responses. Sometimes when people do not get a sense of safety, they can get stuck between yellow (fair danger) and red (lethal danger). Then, their brains are unable to relate to their environment because their neuroception is biased towards danger.
This can cause trauma and the symptoms that we observe.
Trauma is not a psychological condition but a physiological one. Hence, in order to work with trauma it is important to retrain our physiology in order to create safety first. Otherwise, the brain will think that the person is about to die and will shut down all its functions (freeze state or dissociation.
For more information: https://www.stephenporges.com