Understanding the Neuroscience Behind EMDR Therapy: A Path to Healing

Understanding the Neuroscience Behind EMDR Therapy: A Path to Healing

Author: Alex Penrod, MS, LPC, LCDC

Eye Movement Desensitization and Reprocessing (EMDR) therapy has gained significant recognition as an effective treatment for trauma and post-traumatic stress disorder (PTSD). But how does it work? In this article, we'll explore the neuroscience behind EMDR therapy, shedding light on its mechanisms and why it has become a cornerstone in trauma therapy. By understanding the science, therapists and clients alike can appreciate the profound impact of EMDR on trauma resolution and greater well-being in general. 

What is EMDR Therapy?

EMDR therapy is a structured approach to psychotherapy that involves the client recalling distressing experiences while engaging in bilateral stimulation, such as side-to-side eye movements, tapping, or auditory tones. This process helps to reprocess and integrate traumatic memories, reducing their emotional impact.

The Brain and Trauma

To understand how EMDR therapy works, it's essential to first grasp how the brain processes trauma. When a person experiences a traumatic event, the brain's natural processing abilities can become overwhelmed, leading to the event being improperly stored in the memory. This can result in the persistent intrusion of traumatic memories, which can trigger intense emotional and physiological responses. When a person is triggered by a traumatic memory or external trauma reminder, they are not remembering it as if it is in the past, it is as if the body and brain believe the event is happening again right now in the present. 

The Role of the Amygdala, Hippocampus, and Prefrontal Cortex

Three critical regions of the brain are involved in the processing of traumatic memories: the amygdala, hippocampus, and prefrontal cortex.

1. Amygdala: This almond-shaped set of neurons is the brain's emotional center, responsible for detecting fear and preparing for emergency events. During a traumatic event, the amygdala becomes highly active.

2. Hippocampus: This region is involved in forming, organizing, integrating, and storing memories. It helps in contextualizing and distinguishing past from present experiences. The way it organizes and integrates our memories become our identity and life story. Trauma can disrupt the hippocampus’s ability to integrate memories correctly leaving them unprocessed in a disintegrated state.

3. Prefrontal Cortex: This part of the brain is responsible for executive functions, such as decision-making, rational thought, and emotional regulation. Trauma can impair the prefrontal cortex’s ability to modulate the amygdala's response to fear. Think about how quickly you can slam on the brakes in your car if someone stops short in front of you. That is your amygdala overriding your prefrontal cortex to respond faster than you can think. It’s helpful when you need it, but trauma and PTSD cause this to happen in inappropriate and disruptive ways. The amygdala starts running the show and is not easily convinced that the danger has passed. 

Bilateral Stimulation and Memory Processing

EMDR therapy utilizes bilateral stimulation (BLS), which involves rhythmic left-right patterns of eye movements, taps, or auditory tones. The exact mechanism of BLS is not fully understood, but several theories provide insights into its effectiveness:

1. Adaptive Information Processing (AIP) Model: The AIP model suggests that trauma disrupts the brain’s information processing system, leaving the traumatic memory stuck in its original form. BLS during EMDR therapy helps to reactivate the brain's natural processing abilities, enabling the integration and resolution of traumatic memories. It is also thought that by activating both hemispheres of the brain while recalling a traumatic memory this recreates a brain state similar to REM sleep in which memories are processed and integrated naturally each night. 

2. Dual Attention Stimuli: BLS provides dual attention stimuli, where the client focuses on both the traumatic memory and the external stimuli (e.g., eye movements). This dual focus may reduce the emotional intensity of the memory, allowing for more effective processing. The dual attention aspect can help explain why EMDR allows for successful reprocessing of memories while REM sleep tends to just produce nightmares that further traumatize a person. It seems the AIP network needs the aid of BLS to calm the amygdala and make reprocessing tolerable for it to be effective. 

3. Working Memory Theory: This theory posits that BLS taxes the working memory, which is limited in capacity. When the working memory is occupied with BLS, it has less capacity to fully engage with the traumatic memory, diminishing its vividness and emotional impact. This makes sense as another way to throttle and titrate memory exposure so it can be tolerated instead of creating flooding and overwhelm. 

Neurobiological Changes with EMDR Therapy

Research has shown that EMDR therapy can lead to significant neurobiological changes in the brain. Some of these changes include:

1. Reduction in Amygdala Activation: EMDR therapy has been associated with decreased activation of the amygdala, leading to reduced fear and anxiety responses when recalling traumatic memories.

2. Increased Prefrontal Cortex Activity: Enhanced activity in the prefrontal cortex has been observed following EMDR sessions, indicating improved emotional regulation and cognitive control over traumatic memories. The research that discovered this potential mechanism of action made EMDR the first psychotherapy to have a proven neurobiological effect (Pagani, et al. 2013).

3. Hippocampal Integration: EMDR may facilitate better integration of traumatic memories within the hippocampus, aiding in contextualizing the trauma and distinguishing it from present experiences. For an interesting article on some recent discoveries about the hippocampus click here.

Clinical Evidence and Effectiveness

Numerous studies have demonstrated the effectiveness of EMDR therapy in treating PTSD and other trauma-related disorders. EMDR has shown to be effective with multi-event trauma as well. EMDR is endorsed as a first line treatment for PTSD by the American Psychiatric Association, The Department of Veterans Affairs, and the World Health Organization, ranking EMDR along with Trauma Focused - Cognitive Behavioral Therapy (TF-CBT).  Clinical trials have shown that EMDR can lead to significant reductions in PTSD symptoms, with clients often no longer meeting criteria for PTSD. A notable difference from other therapies is that EMDR can often accomplish these benefits in fewer sessions, without needing to describe details of events, and with no homework involved outside of session. For a comprehensive list of all the research on EMDR click here.

Conclusion

Understanding the neuroscience behind EMDR therapy not only enhances its credibility but also provides hope to those suffering from PTSD and complex trauma. By harnessing the brain's natural healing processes, EMDR offers a powerful tool for therapists to help their clients reprocess and overcome traumatic memories. As research continues to uncover the intricacies of how EMDR works, its application in therapy will only become more refined and effective.

Alex Penrod, MS, LPC, LCDC

August 5th, 2024

References

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4. Pagani, M., Högberg, G., Fernandez, I., & Siracusano, A. (2013). Correlates of EMDR therapy in functional and structural neuroimaging: A critical summary of recent findings. Journal of EMDR Practice and Research, 7(1), 29–38.

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