Our brains have a natural way to recover from traumatic memories and events. This process involves communication between the amygdala (the alarm signal for stressful events), the hippocampus (which assists with learning, including memories about safety and danger), and the prefrontal cortex (which analyzes and controls behavior and emotion). While many times traumatic experiences can be managed and resolved spontaneously, they may not be processed without help.
Stress responses are part of our natural fight, flight, or freeze instincts. When distress from a disturbing event remains, the upsetting images, thoughts, and emotions may create an overwhelming feeling of being back in that moment, or of being “frozen in time.” EMDR therapy helps the brain process these memories, and allows normal healing to resume. The experience is still remembered, but the fight, flight, or freeze response from the original event is resolved.
Read more here: About EMDR Therapy – EMDR International Association (emdria.org)