Eye Movement Desensitisation and Reprocessing (EMDR) is best known as a therapy for trauma, but many people wonder: what actually happens in the brain during EMDR?

While research is still evolving, studies in neuroscience and psychology give us helpful insights into why EMDR can be such a powerful way of healing.

Trauma and the Brain

When we experience trauma, the brain’s natural memory processing system can become overwhelmed. Instead of being stored as a normal memory, the experience may get “stuck” in the brain’s fear centres (such as the amygdala). This can mean the sights, sounds, and feelings from the event remain raw and unprocessed, leading to flashbacks, nightmares, or strong emotional reactions long after the danger has passed.

The Role of Bilateral Stimulation

In EMDR, clients focus on a distressing memory while engaging in bilateral stimulation (eye movements, taps, or tones alternating from left to right). This back-and-forth action activates both sides of the brain in a rhythm similar to what happens during REM sleep – the phase of sleep when we naturally process memories.

This seems to allow the brain to “unstick” the traumatic memory and move it into the normal memory networks, where it loses its emotional intensity and becomes part of the past, rather than a present threat.

Mechanisms at Work

Several mechanisms are thought to explain why EMDR works:

1. Memory Reconsolidation
   • During EMDR, the traumatic memory is reactivated in a safe setting.
   • Bilateral stimulation seems to allow the brain to update and re-store the memory in a less distressing form.
2. Dual Attention
   • Focusing on the memory and the external stimulus (eye movements/taps) divides attention.
   • This reduces overwhelm, helping clients to stay grounded while recalling difficult experiences.
3. Working Memory Taxation
   • Holding a traumatic image in mind while tracking eye movements uses up working memory.
   • This makes the memory less vivid and less emotionally charged, reducing its power.
4. Calming the Nervous System
   • EMDR has been shown to reduce hyperactivity in the amygdala (fear centre) and increase activity in the prefrontal cortex (the rational, calming part of the brain).
   • Over time, this helps restore balance between the emotional and thinking parts of the brain.

A Natural Healing Process

The best way to understand EMDR is to see it as unlocking the brain’s natural healing ability. Just as the body can heal from physical wounds, the brain has the capacity to heal from emotional wounds – once the blockage is removed. EMDR provides the conditions that make this possible.

Final Thoughts

Research continues to deepen our understanding of EMDR, but what’s clear is that this therapy doesn’t erase memories – it changes how they are stored in the brain. Traumatic events become memories that can be thought about without overwhelming distress.

For many people, this means not only relief from symptoms, but also a greater sense of resilience and freedom in everyday life.