This is your brain on trauma


Veterinary professionals: Once you understand how and why trauma affects the body, you can reverse its negative effects. Read on to learn how your brain and body change in response to traumatic stress. you were alive in the 1980s you may recall a public service announcement in which an unseen announcer states, “This is your brain,” accompanied by an image of a raw egg. The announcer then says, “This is your brain on drugs,” as a pair of hands proceeds to crack the egg into a hot frying pan.

You may also remember from biochemistry class that when a protein is heated it undergoes an irreversible chemical reaction and becomes denatured. That fried egg can never return to its raw state.

Trauma causes similar changes in the brain, where chemical reactions occur and states of being are altered. The good news is these that reactions and changes are reversible; trauma is less like frying an egg and more like freezing water into a block of ice or boiling it into steam. The bad news is that the processes required to reverse the effects of trauma can be a lot more complex than collecting condensation or melting ice. But it is possible.

To understand how to reverse the reactions or seek individuals who can help, one first must understand how the brain changes in response to traumatic stress. Understanding this will also provide insight into why certain healing modalities are more effective than others.

Behaviors that result from trauma are not necessarily due to moral failings, lack of willpower or bad character. Instead, they are caused by chemical changes in the brain, just like a chemical reaction that freezes water into ice.

Not everybody reacts the same exact way to trauma, just as boiling and freezing points differ depending on the purity of the water (e.g. how much salt is in it). One's likelihood of becoming traumatized depends on the situation and the environment. This article outlines the most common ways trauma manifests in the brain and body.

Faulty brain alarm system

The amygdala, part of the brain's limbic system, normally identifies input relevant for survival. It will immediately activate our fight-flight-freeze reaction (see Long-term physiologic effects of the stress response) if it identifies a threat.

Long-term physiologic effects of the stress response

When a person perceives danger, real or not, their body reacts in less than 1/20th of a second. This is known as the fight-flight-freeze reaction. If the trauma is not resolved, the stress hormones the body secretes to protect itself keep circulating, and the defensive movements and emotional response keep getting replayed. Regular activation of the stress response in non–life-threatening situations can have long-term detrimental effects on our health:

• Heart rate and blood pressure increases can lead to heart disease.

• Increased stress hormone levels can lead to anxiety, insomnia and addictions.

• Shunting of blood from the digestive organs to the muscles can cause gastrointestinal illness.

• Decreased insulin levels and increased glucagon, cortisol and adrenaline levels can lead to diabetes and obesity.

• Immune system suppression can lead to infection, cancer, and other illnesses.

• Decreased growth and sex hormone levels can lead to premature aging.

Traumatologists like to refer to the amygdala as the smoke detector in our brain, as it will activate an alarm if there is danger. Unresolved trauma increases the risk of misinterpreting whether a situation is dangerous or safe, thereby creating a faulty alarm system. People who have experienced trauma often are triggered to react as if they are in danger in situations that are not actually threatening.

Consider this:Alex Honnold, the first person to free climb Yosemite National Park's El Capitan, has an amygdala that does not respond to fear in the same way as the average person's. Neuroscientists have performed numerous brain imaging studies on him and are still trying to figure out why his amygdala does not respond in situations of mortal danger, such as climbing a 3,000-foot vertical rock formation without using ropes. It is not that he doesn't feel fear at all; rather, he has likely been able to train his brain to not engage the sympathetic nervous system (flight-fight-freeze mode) during extremely dangerous situations.

Cats and I have a very turbulent relationship. I was never a fan before my career and after being bit on my first day as a vet tech assistant, it went downhill from there. As my skill set grows I'm slowly trying to expand my understanding of them and trying to find a middle ground between caution and compassion.


Right brain versus left brain

Brain imaging studies1-3 have shown that traumatic events tend to activate the right hemisphere of the brain and deactivate the left. The right brain is the intuitive, emotional, visual, spatial, tactile and artistic side. It stores memories of sound, touch and smell. The left brain is the rational, logical, linguistic, sequential and analytical side. It remembers facts, statistics and language.

What does this all mean in trauma? Deactivation of the left hemisphere has a direct impact on a person's capacity to organize experiences into logical sequences (Broca's area, one of the brain's speech centers, which blacks out during trauma, is on the left side). This may contribute to why people sometimes find it difficult to verbalize their trauma or why talk therapy alone may not be enough to heal from posttraumatic stress disorder (PTSD) or secondary traumatic stress disorder (STSD).

Consider this: The right brain is the first side to develop in the womb and carries the nonverbal communication between parents and infants for the first one to two years of life before a child learns to speak. Nonverbal ways of soothing and nurturing children are often more effective than trying to use language in the first 2 years of life. Yet this is forgotten when one reaches adulthood as nonverbal soothing techniques are used less often.

I keep my golden retriever in my office solely to hug and cuddle when I have a bad day.


Loss of executive function

When something reminds a person of past trauma, their right brain reacts as if the traumatic event were happening in the present. Because the left brain isn't working very well, however, they might not be aware that they are experiencing and reenacting the past. They are furious, terrified, ashamed or frozen. After the emotional storm passes, they may look for something or someone to blame for it. It is a feeling often described as “losing your mind.” It's difficult to make sense of what is happening because the left side of the brain is less active. This is why being “trauma-informed” can help people respond to these situations more effectively, whether you are observing it happen to someone else or it is happening to you.

Consider this: When words fail to soothe someone who is experiencing a traumatic event, tactile stimulation, soothing sounds or pleasant smells may often prove effective. You may also employ this on yourself. One can also try to re-engage the left brain by counting to 10 or by naming every object they see in the room. Often both modalities can be employed together, such as tapping on your chest and counting to 10 at the same time. Using bilateral stimulation (i.e. engaging both sides of your brain) may also help with restoring executive function

[I was] attacked by a cat my first job. I had to get four stitches and a round of rabies [prophylaxis]. Now I can't stand cats or holding one. PTSD? P.S. - The owner screamed at me saying it was my fault.



Numbing out

This is also known as losing one's sense of self or feeling dead inside, especially in situations that warrant emotion. In the veterinary profession, we sometimes like to joke that we are dead inside, and it's funny, we laugh about it. But at the same time we know it's not really funny because it is a sort of pathology. Outward manifestations may include blank stares, absent minds and difficulty living in the present or responding emotionally to emotionally charged situations. The feeling can also be described as feeling disembodied. Perhaps even wondering why you can't feel sad…

Sometimes, when I walk out of a euthanasia and put a smile back on my face, I wonder where all the sadness goes...


Trauma-induced aphasia

Have you ever seen or heard something that left you speechless? Perhaps your jaw dropped, or you opened your mouth to speak but nothing came out. Neuroscientists and trauma researchers have discovered that during traumatic events, the part of our brain that is associated with language may shut down temporarily.

Consider this: In one brain imaging study, a patient was intentionally re-traumatized 13 years after a traumatic event.4 The biggest area of brain activation during the event was found to be in the right limbic area (amygdala). Decreased activity was noted in Broca's area in the left frontal lobe of the cortex. Stroke victims whose blood supply to Broca's area is cut off will lose the ability to speak. It is almost akin to having a stroke but there is no actual blood clot obstructing flow; instead, it is the brain's natural response to trauma.

As a future CVT, the vet I am shadowing yelled at me when I asked a question. I cried. Please be nice. I am just trying to learn!


Dissociating and reliving

Dissociation is the essence of trauma. The overwhelming experience is split off and fragmented, so that the emotions, sounds, images, thoughts and physical sensations related to the trauma take on a life of their own. The sensory fragments of memory intrude into the present, where they are literally relived. If the trauma is not resolved, the stress hormones that the body secretes to protect itself keep circulating, and the defensive movements and emotional response keep getting replayed. One may have no idea why they respond to some minor irritation as if they were about to be annihilated. Perhaps even something as simple as an employee asking for a raise…

Asked employer for pay raise, accused of it being a personal attack and was forced to apologize to him. Gave my notice a week later. Now making a lot more and happier at my new practice. #knowyourworth


Sensory overload

The thalamus (also part of the brain's limbic system) helps to distinguish between sensory information that is relevant and information that you can safely ignore. For instance, if you are sitting down reading this right now, your body is receiving sensory input from your buttocks, arms and legs that there is pressure against your body. However, this is filtered in a way as irrelevant, so you're not constantly aware of the pressure (sensory input) of the chair or floor against your body. This is so your brain can ramp up sensory input that is more relevant, such as sound or visual input related to the task you are performing.

Traumatologists like to say the thalamus acts as a filter or gatekeeper. This makes it a central component of attention, concentration and new learning, all of which are compromised by unresolved trauma. People with unresolved trauma are constantly on high alert, may experience tunnel vision, and may have difficulty concentrating.

Consider this: People with PTSD or STSD have their floodgates wide open, lacking a filter; they are on constant sensory overload. To cope with the overwhelming feelings, they attempt to shut themselves down and block out the world, often with drugs or alcohol. They may become less social, spend more time hiding out or become reclusive. The tragedy is that the price of shutting down includes filtering out sources of pleasure and joy as well. The thalamus can be recalibrated effectively through trauma-based therapy just as one may recalibrate a scale or other measurement tool.

Funny, in vet school we called it "partying" and "unwinding." As a DVM it's called "binging" and "alcoholism." Wish I'd have started kicking that out in school...


Loss of feeling safe

Being able to feel safe with other people is probably the single most important aspect of good mental health. Safe connections are fundamental to meaningful and satisfying lives. Social support is the most powerful protection against becoming overwhelmed by stress and trauma. Research over the past two decades has shown that when people become too skittish or shut down to derive comfort from other humans, relationships with mammals can help.

Stayed in a job where my boss bullied me relentlessly for two years. He destroyed my confidence to the point where I could not take a blood sample if he was in the room, my hands shook so much. The day before I quit, he told me that I was basically unemployable and would never find another job. I am five months into a new job that I LOVE.


Controlling the stress reaction

If the amygdala is the smoke detector of the brain, the frontal lobes-and specifically the medial prefrontal cortex-located directly above our eyes, can be considered the watchtower. In PTSD or STSD, the critical balance between the amygdala and the medial prefrontal cortex shifts radically, making it harder to control emotions and impulses. Effectively dealing with stress depends on restoring this balance so you don't go into flight-fight-freeze mode every time, and you can respond from a place of awareness.


1. Bremner JD. Traumatic stress: effects on the brain. Dialogues Clin Neurosci 2006;8(4)445-461.

2. Hartley CA, Phelps EA. Changing fear: the neurocircuitry of emotion regulation. Neuropsychopharmacology 2010;35(1):136-146.

3. Van der Kolk B. Posttraumatic stress disorder and the nature of trauma. Dialogues Clin Neurosci 2000;2(1):7-22.

4. Van der Kolk B. Looking into the brain: The neuroscience revolution. In: The body keeps the score: brain, mind, and body in the healing of trauma. New York: Penguin House; 2015:40-47.

Frequent Fetch dvm360 speaker Dr. Hilal Dogan practices medicine in Denver, Colorado. She started the Veterinary Confessionals Project as a senior veterinary student at Massey University in New Zealand.

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