EMDR is based on the Adaptive Information Processing (AIP) model, which shows how psychological distress results when memories of adverse life experiences aren’t efficiently processed and become stored in a maladaptive form. When a traumatic or distressing event occurs, the brain may not fully integrate the memory due to its intensity or complexity.

Through the use of bilateral stimulation (typically eye movements, tapping, or auditory tones), EMDR facilitates the reprocessing of these memories. More specifically, bilateral stimulation activates both hemispheres of the brain. This dual attention stimulus is not just a technical tool; it mirrors the neurological activity that occurs during rapid eye movement (REM) sleep, the phase of sleep when the brain naturally processes and consolidates emotional memories.

EMDR impacts brain regions involved in memory, threat detection, and emotional regulation, particularly the amygdala, hippocampus, and prefrontal cortex. These three structures in the brain work dynamically: the amygdala signals danger, the hippocampus places the experience in context, and the prefrontal cortex helps regulate the response and make meaning. In trauma, this system becomes dysregulated—often with an overactive amygdala, underactive hippocampus, and decreased prefrontal cortex activity. EMDR specifically works to rewire the brain to help these regions understand that there is no longer a threat.