Reviewed by Monica Vilhauer Ph.D.

Source: cdn2.psychologytoday.com

When people with post-traumatic stress disorder (PTSD) recall traumatic memories, they often experience intense emotional reactions, as if the traumatic event is happening all over again in the present moment. But what’s actually happening in the brain that makes traumatic memories feel so real and overwhelming?

Source: cdn2.psychologytoday.com

A recent study, conducted by Dr. Ruth Lanius and Lauren Rudolph, aimed to understand this phenomenon by comparing the brains of people with and without PTSD when they recall traumatic memories. The results were fascinating and have important implications for treatment.

What is Trauma?

Before we dive into the study’s findings, let’s define what trauma is. Trauma is a deeply distressing or disturbing experience that can have a lasting impact on a person’s mental and emotional well-being. PTSD is a condition that can develop after a person experiences a traumatic event, and it’s characterized by symptoms such as flashbacks, nightmares, and avoidance of triggers that remind them of the trauma.

Key points from the study include:

• People with PTSD often struggle to feel safe and grounded when they recall traumatic memories.
• The study is the first to look at connections across the entire brain while people recall traumatic memories, rather than focusing on isolated brain regions.
• The study found that people with PTSD (both Classic PTSD and the Dissociative Subtype of PTSD) had weaker connections between different layers of the brain that are involved in coordinating thinking, emotions, and physical responses.
• In people with PTSD, the survival brain (midbrain and cerebellum) is not connected enough to the reflective brain (the cortex), and these connections are critical for updating someone to a felt sense of safety.

So, what does this mean for people with PTSD? When recalling traumatic memories, the PTSD-impacted brain may rely more on basic survival responses (e.g., fight, flight, freeze) and less on the brain functions that help people notice the present and realize the memory is in the past. This could explain why traumatic memories in PTSD often feel so real and overwhelming – these memories feel as if they are happening right now, in the present.

What Did the Study Discover?

The study used functional magnetic resonance imaging (fMRI) to compare the brains of people with and without PTSD while they recalled traumatic memories. The participants were asked to recall a neutral memory and a traumatic memory during the fMRI scan. The traumatic memory involved a “moral injury” — a traumatic event involving a need to act against one’s own code of ethics, or witnessing someone else doing so.

The study found that people with PTSD (both Classic PTSD and the Dissociative Subtype of PTSD) had weaker connections between different layers of the brain that are involved in coordinating thinking, emotions, and physical responses. In people with PTSD, the survival brain (midbrain and cerebellum) is not connected enough to the reflective brain (the cortex), and these connections are critical for updating someone to a felt sense of safety.

The study also found that people with PTSD had increased connections within the cerebellum when recalling traumatic memories. This means that the cerebellum (the prediction center) ends up working on its own, rather than sending and receiving important updates from the cortex and other areas of the brain that can signal that we are now safe.

The study’s findings have important implications for treatment. It suggests that treatment needs to restore vertical integration to improve the brain’s capacity to update information. This could help re-establish the sense that “I am safe” again.

Overall, the study provides new insights into the brain’s response to trauma and has important implications for treatment. By understanding how the brain responds to traumatic memories, we can develop more effective treatments that help people with PTSD feel safe and grounded again.