When a person experiences a traumatic event, adrenaline rushes through the body and the memory is imprinted into the amygdala, which is part of the limbic system. The amygdala holds the emotional significance of the event, including the intensity and impulse of emotion. 

The amygdala stores the visual images of trauma as sensory fragments, which means the trauma memory is not stored like a story, rather by how our five senses were experiencing the trauma at the time it was occurring. The memories are stored through fragments of visual images, smells, sounds, tastes, or touch.

Consequently, after trauma, the brain can easily be triggered by sensory input, reading normal circumstances as dangerous.  The sensory fragments are misinterpreted and the brain loses its ability to discriminate between what is threatening and what is normal.

The front part of our brain, known as the prefrontal cortex, is the rational part where consciousness lives, processing and reasoning occurs, and we make meaning of language. When a trauma occurs, people enter into a fight, flight, or freeze state, which can result in the prefrontal cortex shutting down. The brain becomes somewhat disorganized and overwhelmed because of the trauma, while the body goes into a survival mode and shuts down the higher reasoning and language structures of the brain. The result of the metabolic shutdown is a profound imprinted stress response.