The Neurobiology of Trauma

The neurobiology of trauma involves complex changes in brain structure, function, and chemistry that alter how the brain processes stress, emotions, and memories. Three key brain regions play central roles:

• The amygdala acts as the brain’s alarm system, detecting threats and triggering a "fight, flight, or freeze" response. After trauma, it can become hyperactive, leading to heightened fear, anxiety, and hypervigilance.

• The hippocampus, which organizes and contextualizes memories, often shrinks or functions less effectively after trauma. This can lead to fragmented or overly vivid memories and difficulty distinguishing past trauma from present experiences.

• The prefrontal cortex (PFC), responsible for executive functions such as decision-making and emotion regulation, tends to have decreased activity during trauma responses. This reduces the brain’s ability to control fear responses and regulate impulses.

  
  

Neurochemical systems, including cortisol, norepinephrine, and serotonin, also become dysregulated after trauma, contributing to sustained stress responses and reinforcing traumatic memory pathways. For example, low cortisol at the time of trauma can lead to overactivation of stress hormones that enhance traumatic memory encoding and reduce the inhibition of recalling these memories.

These alterations contribute to the symptoms of PTSD, such as intrusive memories, emotional dysregulation, hyperarousal, and avoidance. Understanding these neurobiological foundations highlights why treatments focus on restoring regulation, safety, and balanced brain function to promote healing and resilience after trauma.