THE SCIENCE OF HEALING
How Does EMDR Work?
Bilateral stimulation, the eight-phase protocol, & the neuroscience behind EMDR.
The Bilateral Stimulation Engine
At the center of EMDR processing is bilateral stimulation — a rhythmic, left-right pattern that engages both hemispheres of the brain. There are several forms: guided eye movements following the therapist’s hand, tactile buzzers or tapping that alternates between hands, auditory tones that shift between ears, or self-administered techniques like the butterfly hug.
Bilateral stimulation appears to mimic what happens during REM sleep, when the brain naturally processes and consolidates experiences. During waking EMDR processing, this stimulation helps the brain access traumatic memories that have been stored in a fragmented, activated state and begin to integrate them with more adaptive information.
What Happens in the Brain
Traumatic memories (or memories that cause overwhelm) are stored differently from ordinary memories. They’re held in the limbic system — the emotional brain — in raw, unprocessed form. The sights, sounds, smells, body sensations, and beliefs from the original events remain linked together and easily activated by present-day triggers.
During EMDR processing, the memory networks begin to connect with more adaptive information. The emotional charge decreases. The body releases the tension it’s been holding. Negative beliefs like “I’m not safe” or “I’m powerless” lose their grip, and more accurate beliefs can take their place. The memory doesn’t disappear — it gets reorganized so it no longer hijacks your nervous system.
Competing Theories: Why Does Bilateral Stimulation Work?
We don’t yet have a single definitive explanation. Several well-supported theories exist, and the truth may involve elements of all of them.
The REM sleep analogy proposes that bilateral stimulation activates the same neural processes that occur during rapid eye movement sleep, when the brain naturally consolidates and integrates the day’s experiences. EMDR may essentially be facilitating this process during waking hours.
The working memory taxation model, developed by researchers including Andrade and van den Hout, suggests that bilateral stimulation taxes working memory. Because working memory has limited capacity, holding a traumatic image in mind while simultaneously tracking eye movements or tapping reduces the vividness and emotional intensity of the memory. Over repeated sets, the memory loses its charge.
The orienting response theory proposes that bilateral stimulation triggers a natural investigatory reflex — the brain’s response to new stimuli — which shifts the nervous system from a state of alarm to a state of attentive calm.
More recent neuroimaging research has begun examining how EMDR processing affects the default mode network — the brain network active during self-referential thought — and connectivity between the amygdala, prefrontal cortex, and hippocampus. Early findings suggest that EMDR may help restore the communication between brain regions that becomes disrupted by trauma, allowing memories to be properly contextualized and integrated.
What all these theories share is a recognition that EMDR works at a neurological level that talk therapy does not directly access.
EMDR’s Eight Phases
EMDR is sometimes thought to refer to a single technique, but it is much more than that. EMDR is actually an entire therapy system that works through eight phases or components.
Phase 1: History and Treatment Planning. We map your history, identify target memories and their interconnections, and establish treatment goals.
Phase 2: Preparation. Building internal resources, developing somatic awareness, and ensuring you have the capacity to manage what comes up during processing. In my practice, this often includes IFS work to understand the parts of you that may have opinions about this process.
Phase 3: Assessment. Identifying the specific memory to target, the negative belief connected to it, where you feel it in your body, and how disturbing it is.
Phases 4–6: Desensitization, Installation, and Body Scan. This is the active processing — bilateral stimulation while holding the target memory. The disturbance decreases, a positive belief strengthens, and we check for residual tension in the body.
Phase 7: Closure. Ensuring you leave the session grounded and stable, whether or not processing is complete.
Phase 8: Reevaluation. At the next session, we check what’s shifted and what still needs attention.
Integrative EMDR
Standard EMDR is powerful in and of itself. In my practice, I’ve found that integration with other therapy approaches makes it transformative. I weave in Internal Family Systems (IFS) to work with the protective parts that often arise during processing — the part that shuts down, the part that deflects, the part that’s afraid of what comes next. I incorporate somatic awareness because trauma lives in the body, not just the mind. And I work within a relational framework because we heal in connection, not in isolation.
This isn’t a just theoretical preference. It’s what I’ve observed over 30 years of practice: when EMDR is held within a broader integrative container, the work goes deeper, the changes are more stable, and the whole person — not just their symptoms — is addressed.