Traumatic Events Can Cause a Change in Brain Function

By Kekuni Minton, Ph.D.

Trauma causes a variety of responses - physiological, neurological and psychological.

They are fascinating to study, but difficult to personally endure.

Recent research studies shed light on what is happening in the brain and body during and after a traumatic event which have greatly enhanced our understanding of traumatic reactions and how to treat them.

Trauma may be defined as a perceived life threatening experience that overwhelms the nervous system.

Traumatic experiences include domestic violence, emotional abuse, death of a loved one, car accidents, war, sexual abuse, natural disasters, torture and so forth. Many people who feel traumatized long after the disturbing events have passed may suffer post traumatic stress disorder.

By understanding some of the brain changes, people suffering from stress disorder may understand how to deal with these changes more effectively.

During a traumatic event, a person may first try to deal with circumstances using all of his or her available resources. Training, constitution and temperament may be helpful during a traumatic event.

However, everyone has a breaking point, and when this occurs, part of the brain functioning may start to change.

First, as the nervous system begins to be overwhelmed, brain activity in the left hemispheres (the rational, logical processing hemisphere) begins to attenuate and activity in the right hemisphere (in areas associated with emotional arousal) escalates.

As this lateralization happens, the person will feel it is more difficult to "think things through" and may be flooded with emotional reactions. Although this may seem counterproductive, mother nature apparently evolved this as an effective response to some traumatic situations which are best responded to through quick highly motivated action rather than "thinking things through."

Think of a car accident. If the incident is severe, two other areas of the brain start to shut down.

1) The prefrontal cortex, the part of the brain directly behind the forehead, is known for executive functioning, decision making and mindfulness and this brain change may cause a person to stop responding during trauma and actually freeze, like a deer in the headlights. This freeze response may stop a predator from seeing or attacking a potential victim.

2) Broca's area, the part of the left hemisphere responsible for translating personal experiences into language, shuts down.

This is why during a traumatic event a person may be literally "scared speechless." It is theorized this change may be why even after a terrifying event it may be difficult to put it into words.

While these cortical (the outer undulating parts of the brain) areas are changing their style of functioning, structures deeper in the middle brain known as the limbic system, start to light up.

The amygdala (meaning almond shaped) is a structure that acts like a "smoke alarm" and attributes heightened anxiety to traumatic experiences and causes a "worry circuit" to be initiated.

As noted, each of these changes in the brain may actually help during the event of the trauma.

However, they can weak havoc after the event has passed, with deteriorated mental responsiveness, rational thinking, language processing, etc.

The changes may cause problems with memory storage of a traumatic event, where sensory elements (sounds, smells, etc.) may predominate, but the narrative explanation and understanding of the events may be partially or entirely missing.

The memory may become state specific; that is, when the memory is triggered by similar stimuli, the person may easily over-access the details of the memory. However, in every day life, without relevant stimuli, the memory may be difficult to access.

All of these brain changes affect functioning of the body, often causing the individual to respond to stimuli in his or her environment as if back at the "scene of the crime." As van der Kolk states, trauma survivors "are prone to go immediately from stimulus to response without making the necessary psychological assessment of the meaning of what is going on.

"This makes them prone to freeze or alternatively, to overreact and intimidate others in response to minor provocations."

Thus, a trauma survivor tends toward two extreme poles of the spectrum of arousal:

1) Hyperarousal and hypervigilant reactions, or 2) freeze or even catatonia, where the nervous system begins to dramatically shut down. Some survivors swing between two states.

The obvious question is, how do we treat these radical changes in brain and body functioning?

First, it is important to recognize these changes may have occurred. Even if a person has an I.Q. of 180, after a traumatic event s/he may be at a loss for words or understanding of what has happened.

This may make an intelligent person feel "crazy" for awhile. Also, there may be an ongoing tendency for stimuli similar to the original trauma to cause hyperreactions.

Second, in some cases, slowing down and mindfully processing physiological reactions to certain stimuli may reduce symptoms.

This mindful exploration may reengage lost elements of brain functioning and may help change the way a person responds to the same stimuli (mindfully and rationally rather than hysterically).

Third, time and perhaps psychotherapeutic and/or psychopharmacological treatment may be helped in allowing these brain changes to re-adjust and in some cases, reset.