There has been an increasing interest in understanding trauma and the brain. Ideas like the body “keeping score” have helped to popularize the effects of PTSD on the nervous system. Interest in brain functioning is helpful for clinicians. But the study of neurological processes in PTSD has been around long before reaching popularity.
The activation of the body’s fight or flight system following continued reminders of a traumatic event(s) has been foundational for this research. Findings from the mid-1990s onward then began to understand specific roles played by some of the brain’s key structures related regulating emotions.
The amygdala and the prefrontal cortex are notable brain structures for understanding trauma and the brain. The amygdala is a brain structure that plays a key role in the experience and expression of many emotions. It is especially important in fear responding. This structure also coordinates bodily responses that go along with emotions (e.g., facial expressions, activation of fight/flight/freeze, etc.).
The prefrontal cortex is a newer region (in terms of evolution) toward the front of the brain. It has been found to be related to reasoning, facilitating goals, and weighing priorities in the face of competing demands. The prefrontal cortex often functions as a “brake system” for many of our emotional responses. That is, it helps us regulate our actions to fit social and other demands while we experience emotions. For instance, not yelling at the person taking a long time to write a check in the grocery line, lest we be ostrasized. (But really, who writes checks these days??)
Research from 2000 has uncovered that individuals who experience PTSD show dramatically increased amygdala activation in the face of difficult stressors. At the same time, the prefrontal cortex also showed decreased activation for those individuals. This suggests that individuals with PTSD experience heightened emotional responses along with a decreased ability to regulate those emotions.
It gets harder. There are also large tracts of brain cells that connect these two regions, allowing them to interact with each other. But those connections appear to be more limited for those who experience trauma. Plus, very recent research found that the cerebellum (which coordinates movement and balance in a way that influences emotion and memory) is also smaller in PTSD.
So chicken or egg? Well, it is difficult to tell whether PTSD leads to these brain differences or vice versa. Researchers usually conduct these neurological studies following a traumatic event, as opposed to beforehand. One thing is clear, however: These differences do help us understand relationships between PTSD responses and brain functioning!
