How Trauma Affects Your Brain

The 1990’s unleashed a neuroscience revolution, as novel brain-imaging techniques allowed scientists to process information in real time. For the first time in history, scientists watched human brains process memories, sensations and emotions. They were able to map the circuits of the mind and consciousness.

Suddenly, they could show us images of our brains on trauma and explain what was happening.

Bessel Van Der Kolk, M.D

Much of what you are about to see and read is drawn from Dr. Van Der Kolk’s work as described in his book, The Body Keeps The Score. If you read no other book on trauma, read this one.

In 1994 Dr. Van Der Kolk and Scott Rauch – a Harvard trained psychiatrist who’d just been appointed director of the brand new Massachusetts General Hospital Neuroimaging laboratory – began a study of what happens in the brains of people having flashbacks. People who’ve experienced trauma often have these flashbacks, where their consciousness is suddenly “hijacked” by images, feelings and sounds from the past. Sometimes they’re so strong you believe you’re back in the time of the event itself, no longer in the safety of now. It’s disorienting, scary, and sometimes impossible to predict.

Rouch and Van Der Kolk had 8 volunteers who were prone to trauma flashbacks. They worked with the volunteers in advance to create a script for a 3rd party to read describing a traumatic scene from the past. On an appointed day, the volunteer would be placed inside the scanner while their scripts were read. Immediately each subject began to have physiological reactions identical to the experience of the trauma itself. Clearly, the mind and body were “stuck,” unable to tell the difference between past and present.

After the scans were completed, Rouch created the following composite images of the scans. They show 3 vital breakthroughs in understanding Your Brain On Trauma:

Image Credit: The Body Keeps The Score (Van Der Kolk, 2014)

Image A shows intense activation of the limbic area, or emotional brain. It was already known that intense emotional experiences activated this area, particularly an area within it called the amygdala. The amygdala’s job is to warn us of impending danger, and to activate the body’s stress response.

This study showed that just by being reminded of traumatic events – even years later – the brain of someone who’s been through trauma will react as if the danger is occurring right now. The amygdala springs into action and triggers the cascade of stress hormones that drive up blood pressure, heart rate and oxygen intake. This is preparing the body for fight or flight.

Image B shows two remarkable things. The visual cortex is stimulated, but only on the right side. The entire left hemisphere seems to have gone “offline.”

What does this mean? Different sides or “hemispheres” of the brain process events and memories differently. In Dr Van Der Kolk’s words, they “speak different languages.” The left side remembers facts, statistics, and the vocabulary of events. It keeps track of the chronological order of events. The right brain stores memories of sound, touch smell, and emotions. This is what we remember from traumatic events – a sound, a smell, a face, a voice. And the fear we felt. We remember these in flashes that are often impossible to piece together.

Having the left side of the brain effectively “shut down” hampers our ability to organize our experience into logical sequences and to translate feelings and perceptions into words. This is why victims of violent crimes often can’t “get their story” together. Why it’s so difficult for them to stand up to meticulous cross-examination in court. They’re not lying – it’s just that the part of their brain responsible for the facts, chronological sequence of events, etc, went offline during the event and will continue to do so whenever the event is remembered.

Finally, Image C highlights a region of the brain known as Broca’s area. This is one of the speech areas of the brain, often affected in stroke patients. Without a functioning Broca’s area, you cannot put your thoughts and feelings into words.

In the image above (harder to tell in black and white) the coloring actually shows a dramatic decrease in that area of the brain. In other words, a critical area of the brain for putting thoughts and feelings into words shuts down whenever a traumatic event occurs, and when it is remembered during a flashback.

In my own experience, something as simple as a turn of phrase often used by one of my parents, or even sometimes the mention of an event from my childhood leaves me suddenly mute. Sometimes I can mumble a few words of gibberish, but often I am struck completely silent until my brain catches back up with the present circumstances.

This basic information is, of course, just scratching the surface. If you or anyone you love deals with trauma, I urge you to get a copy of The Body Keeps The Score. Plan to read it more than once, and keep a highlighter, pen and notebook handy each time. Consider it the owner’s manual for a traumatized brain.

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