John Rigg: The Effect of Trauma on the Brain and How It Affects Behaviors (Transcript)

Here is the full transcript of physiatrist John Rigg’s TEDx Talk: The Effect of Trauma on the Brain and How It Affects Behaviors at TEDxAugusta conference. This event took place on January 30, 2015. Dr. John Rigg is the director of the Traumatic Brain Injury Clinic at Fort Gordon.


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John Rigg – Physiatrist

I want to ask you to think back to some occasion in your life when you might have gotten in an argument with someone, particularly someone that you loved, you cared for a lot — a family member, a spouse, a parent and really reacted — really reacted, you got so angry, did things, you said things, maybe broke stuff, said hurtful things and then later on reflected on your behavior and wondering what happened: where did that come from?

I want to look at some of the factors that contribute to that type of overreaction, that mechanism, that hyper arousal that occurs. Hyper arousal, anger, hostility — where does that come from? What generates it?

I’m going to talk about stress, OK. Stress as a factor that can influence behaviors and look at the anatomy of the human brain — we actually have two brains that are contributing to our behaviors. Two brains contributing to our behaviors. And stress is particularly influential on one of them.

Stress is nothing that we think about, right? We don’t come up with stress. It is a reaction to the external environment. So let me talk about the two brains.

I have a diagram here of the cortex of the brain and this structure underneath the cortex of the brain, which is labeled brainstem in here. But I’m really going to talk about the subcortical brain, this entire structure here.

The cortex of the brain is what I’m going to call the human brain, the intelligent brain. It’s where our personality is, our individuality, where we make choices of our mate, what we eat, what kind of music we listen to, what car we drive, where we live, what type of life we live. We take in sensory information and it’s processed in the cortex, and we take actions based on sensory information. That’s where our personality, our individuality, is all centered in that cortical area.

Note in the human brain, it’s actually — by far the largest mass of the human brain is cortex, OK. We rule the world as humans. Why? Not because we perform animal functions better than any animals; we’re not bigger faster stronger than animals. We think better. We have the largest cortex and we rule the world.

But we’re animals. We eat, make waste products and make babies, and that behavior triggered by our primitive animal brain is sometimes responsible for triggering some of the behaviors that we’re not particularly fond of.

So this primitive animal brain, what does it do? Well, the brain reacts to situations whether we want it to or not. Particularly this animal brain which doesn’t think, it just reacts to the environment. So if I said to you, hey let’s all go outside and race across broad street but don’t your heartbeat increase; could you do it? No.

You can think to yourself, hey I’m going to stop my heartbeat for 10 seconds but you can’t do it. The thought exists, the thinking exists in the cortex, the human brain but the animal brain is controlling your heartbeat and won’t let you do it. So you can think all you want about lowering your blood pressure and it won’t happen. That primitive animal brain is maintaining your heartbeat, your breathing, your digestion from the moment that you’re born, I mean even pre-birth as a fetus, that these structures start operating in that central nervous system, primitive animal brain is operating non-stop until your death. Pretty amazing, OK.

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I’m going to ask you to look at another way that this primitive animal brain reacts to situations, OK. So let’s picture a bunch of guys hanging out arguing about who’s going to win the Super Bowl, on Sunday talking about cars, whatever men might want to talk about when they’re involved in a conversation. I’m a man, so I look at — you know I only have a male perspective on things. But what you guys are sitting around talking.

And all of a sudden during that conversation, this really attractive looking woman walks by with an inappropriately short miniskirt and an inappropriately tight T-shirt, what’s going to happen to that conversation? The little Snickers in the audience, not me, man, I don’t look. Men will be attracted to that, not because they’re out there searching for mates, married men might react that way, OK, but because of the fact there’s an animal instinct of sexual attraction.

Why do advertisers put sexually attractive women in ads? To attract attention to that ad, so people go on buy stuff they don’t need, OK. It’s an animal instinct.

Now I may be distracted at times but I’m married. So I don’t go out and chase the girl. Married men, committed men in relationships might be attracted, might be like a magnetic boom but back focus on hey I’m married. I think the Patriots are going to lose or whatever, you know whatever the conversation is.

But the reaction and I don’t know how women react to men. I mean, fortunately you do react those ugly guys but it’s good. But that primitive sexual instinct is a really important behavioral driver on a day to day basis. Male elephants are attracted to female elephants. Female frogs mate with male frogs. All species, mates, sexual attractions, basic animal instinct.

A more powerful animal instinct programmed in that primitive animal brain is survival. And how do animals survive? Fight or flight, OK, much more powerful instinct.

So the primitive animal brain – to review — runs our body, breathing, digestion, heartbeat, maintains blood pressure and this program for primitive animal instincts that all animals have: eating, sexual attractions, seeking safety and shelter and then that most powerful instinct survival: fight-or-flight.

The cortex of the brain is our thinking brain, it makes decisions, it takes actions at those things, OK, based on sensory information. It thinks, that’s where our memory is located, all of our processing.

Now my job on a daily basis is, I’m a physician, I work — I’m the director of the Traumatic Brain Injury for the military down here at Fort Gordon, Eisenhower Army Medical Center. And I’m going to use some examples of what happens to soldiers when they’re taken from the United States sent over to Iraq and Afghanistan and experience the traumatic experience of war and how does that experience impact their performance, how does that experience impact their behaviors based on the influence that traumatic experience has on their brain whether they wanted to or not, OK.

So what they do is they go to a place like Iraq or Afghanistan. What is the enemy trying to do to them when they’re there? Kill them. The enemy is trying to kill these men and women. So their fight-or-flight, their primitive animal instinct is ramped up and magnified, turn on big time, all the time not for like 20 minutes here and 10 minutes here but non-stop for 24×7 through their entire time of deployment. I was with the patient this morning, seven deployments — seven deployments, 14 months minimum in those seven deployments. Hyperactivated fight-or-flight.

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And when you’re in a place where bad guys are trying to kill you, having your fight-or-flight activated to respond real quickly is the best thing that could happen to you. And it functions great when you’re in a combat zone.

But now let’s take that soldier and return him to the United States. You get on a plane, come back to the U.S., get off the plane, haaaa, I’m back home. What part of the brain is recognizing the geographic shift back to the United States? The cortex, the intelligent human thinking brain. But where was this hyper aroused fighter flight located? In the primitive animal brain, the subcortical brain, specifically a structure called the amygdala which becomes hyper activated and triggers fight-or-flight.

Now that was very very powerful and essential in a combat zone but the soldier now comes home and he’s still hyperactivated. So to give you an example I had one of my men went to – he was home for a few months, he was feeling pretty good, he went to a rock and roll show in Atlanta, hanging out in Atlanta, the concert, was doing OK with the crowds. But all of a sudden, boom, fireworks go off and bam he dives to the ground. Now he didn’t hear the explosion go, that sounds like a bomb, I’d better duck, OK. He reacted non-thinking.

So now let’s look at the anatomy of the brain because there’s one more super important point to make in here that’s fascinating. Sensory information comes in — we see, hear, taste, touch and smell, that sensor information comes into our sense organs, is sent to a structure in the brain except for smell, which bypasses the thalamus but all the rest are sent to the thalamus which is a relay station and it sends a signal to both the human intelligent cortical brain and the primitive animal brain.

So in this case of this explosion at a rock show, the explosion gets to the cortex and the cortex is going to think about it, umm, the explosion sounds like a bomb, wait, I’m in Atlanta. Oh my god, it’s a terrorist bomb. Wait, the band is still playing numbers, running for cover, nobody, there is fireworks, I’m OK. And the cortex could figure that out very quickly.

Simultaneously, that signal went to the animal brain. And the animal brain doesn’t understand geography. It’s hyper activated, it’s hyper activated particularly to explosions which in war meant what, IEDs, rocket-propelled grenades, mortars, blood, guts, death, body parts.

Here’s the second key point about this primitive animal brain. Number one, it doesn’t understand geography. Number two, it’s faster than the thinking brain. The animal brain actually is physiologically wired to respond faster than the thinking brain. So before the soldier can think, that explosion was fireworks, boom, he’s on the ground diving for cover. By the time he hits the ground he’s going oh my god I feel like a jerk down here. Because everybody else is up cheering and he’s on the ground, OK but it was a non-thinking response.