In PTSD the critical balance between the amygdala (smoke detector) and the MPFC (watchtower) shifts radically, which makes it much harder to control emotions and impulses. Neuroimaging studies of human beings in highly emotional states reveal that intense fear, sadness, and anger all increase the activation of subcortical brain regions involved in emotions and significantly reduce the activity in various areas in the frontal lobe, particularly the MPFC. When that occurs, the inhibitory capacities of the frontal lobe break down, and people “take leave of their senses”: They may startle in response to any loud sound, become enraged by small frustrations, or freeze when somebody touches them.13
Effectively dealing with stress depends upon achieving a balance between the smoke detector and the watchtower. If you want to manage your emotions better, your brain gives you two options: You can learn to regulate them from the top down or from the bottom up.
Knowing the difference between top down and bottom up regulation is central for understanding and treating traumatic stress. Top-down regulation involves strengthening the capacity of the watchtower to monitor your body’s sensations. Mindfulness meditation and yoga can help with this. Bottom-up regulation involves recalibrating the autonomic nervous system, (which, as we have seen, originates in the brain stem). We can access the ANS through breath, movement, or touch. Breathing is one of the few body functions under both conscious and autonomic control. In part 5 of this book we’ll explore specific techniques for increasing both top-down and bottom-up regulation.
THE RIDER AND THE HORSE
For now I want to emphasize that emotion is not opposed to reason; our emotions assign value to experiences and thus are the foundation of reason. Our self-experience is the product of the balance between our rational and our emotional brains. When these two systems are in balance, we “feel like ourselves.” However, when our survival is at stake, these systems can function relatively independently.
If, say, you are driving along, chatting with a friend, and a truck suddenly looms in the corner of your eye, you instantly stop talking, slam on the brakes, and turn your steering wheel to get out of harm’s way. If your instinctive actions have saved you from a collision, you may resume where you left off. Whether you are able to do so depends largely on how quickly your visceral reactions subside to the threat.
The neuroscientist Paul MacLean, who developed the three-part description of the brain that I’ve used here, compared the relationship between the rational brain and the emotional brain to that between a more or less competent rider and his unruly horse.14 As long as the weather is calm and the path is smooth, the rider can feel in excellent control. But unexpected sounds or threats from other animals can make the horse bolt, forcing the rider to hold on for dear life. Likewise, when people feel that their survival is at stake or they are seized by rages, longings, fear, or sexual desires, they stop listening to the voice of reason, and it makes little sense to argue with them. Whenever the limbic system decides that something is a question of life or death, the pathways between the frontal lobes and the limbic system become extremely tenuous.
Psychologists usually try to help people use insight and understanding to manage their behavior. However, neuroscience research shows that very few psychological problems are the result of defects in understanding; most originate in pressures from deeper regions in the brain that drive our perception and attention. When the alarm bell of the emotional brain keeps signaling that you are in danger, no amount of insight will silence it. I am reminded of the comedy in which a seven-time recidivist in an anger-management program extols the virtue of the techniques he’s learned: “They are great and work terrific—as long as you are not really angry.”
When our emotional and rational brains are in conflict (as when we’re enraged with someone we love, frightened by someone we depend on, or lust after someone who is off limits), a tug-of-war ensues. This war is largely played out in the theater of visceral experience—your gut, your heart, your lungs—and will lead to both physical discomfort and psychological misery. Chapter 6 will discuss how the brain and viscera interact in safety and danger, which is key to understanding the many physical manifestations of trauma.
I’d like to end this chapter by examining two more brain scans that illustrate some of the core features of traumatic stress: timeless reliving; reexperiencing images, sounds, and emotions; and dissociation.
STAN AND UTE’S BRAINS ON TRAUMA
On a fine September morning in 1999, Stan and Ute Lawrence, a professional couple in their forties, set out from their home in London, Ontario, to attend a business meeting in Detroit. Halfway through the journey they ran into a wall of dense fog that reduced visibility to zero in a split second. Stan immediately slammed on the brakes, coming to a standstill sideways on the highway, just missing a huge truck. An eighteen-wheeler went flying over the trunk of their car; vans and cars slammed into them and into each other. People who got out of their cars were hit as they ran for their lives. The ear-splitting crashes went on and on—with each jolt from behind they felt this would be the one that killed them. Stan and Ute were trapped in car number thirteen of an eighty-seven-car pileup, the worst road disaster in Canadian history.15
Then came the eerie silence. Stan struggled to open the doors and windows, but the eighteen-wheeler that had crushed their trunk was wedged against the car. Suddenly, someone was pounding on their roof. A girl was screaming, “Get me out of here—I’m on fire!” Helplessly, they saw her die as the car she’d been in was consumed by flames. The next thing they knew, a truck driver was standing on the hood of their car with a fire extinguisher. He smashed the windshield to free them, and Stan climbed through the opening. Turning around to help his wife, he saw Ute sitting frozen in her seat. Stan and the truck driver lifted her out and an ambulance took them to an emergency room. Aside from a few cuts, they were found to be physically unscathed.
At home that night, neither Stan nor Ute wanted to go to sleep. They felt that if they let go, they would die. They were irritable, jumpy, and on edge. That night, and for many to come, they drank copious quantities of wine to numb their fear. They could not stop the images that were haunting them or the questions that went on and on: What if they’d left earlier? What if they hadn’t stopped for gas? After three months of this, they sought help from Dr. Ruth Lanius, a psychiatrist at the University of Western Ontario.
Dr. Lanius, who had been my student at the Trauma Center a few years earlier, told Stan and Ute she wanted to visualize their brains with an fMRI scan before beginning treatment. The fMRI measures neural activity by tracking changes in blood flow in the brain, and unlike the PET scan, it does not require exposure to radiation. Dr. Lanius used the same kind of script-driven imagery we had used at Harvard, capturing the images, sounds, smells, and other sensations Stan and Ute had experienced while they were trapped in the car.
Stan went first and immediately went into a flashback, just as Marsha had in our Harvard study. He came out of the scanner sweating, with his heart racing and his blood pressure sky high. “This was just the way I felt during the accident,” he reported. “I was sure I was going to die, and there was nothing I could do to save myself.” Instead of remembering the accident as something that had happened three months earlier, Stan was reliving it.
DISSOCIATION 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. As long as the trauma is not resolved, the stress hormones that the body secretes to protect itself keep circulating, and the defensive movements and emotional responses keep getting replayed. Unlike Stan, however, many people may not be aware of the connection between their “crazy” feelings and reactions and the traumatic events that are being replayed. They have
no idea why they respond to some minor irritation as if they were about to be annihilated.
Flashbacks and reliving are in some ways worse that the trauma itself. A traumatic event has a beginning and an end—at some point it is over. But for people with PTSD a flashback can occur at any time, whether they are awake or asleep. There is no way of knowing when it’s going to occur again or how long it will last. People who suffer from flashbacks often organize their lives around trying to protect against them. They may compulsively go to the gym to pump iron (but finding that they are never strong enough), numb themselves with drugs, or try to cultivate an illusory sense of control in highly dangerous situations (like motorcycle racing, bungee jumping, or working as an ambulance driver). Constantly fighting unseen dangers is exhausting and leaves them fatigued, depressed, and weary.
If elements of the trauma are replayed again and again, the accompanying stress hormones engrave those memories ever more deeply in the mind. Ordinary, day-to-day events become less and less compelling. Not being able to deeply take in what is going on around them makes it impossible to feel fully alive. It becomes harder to feel the joys and aggravations of ordinary life, harder to concentrate on the tasks at hand. Not being fully alive in the present keeps them more firmly imprisoned in the past.
Triggered responses manifest in various ways. Veterans may react to the slightest cue—like hitting a bump in the road or a seeing a kid playing in the street—as if they were in a war zone. They startle easily and become enraged or numb. Victims of childhood sexual abuse may anesthetize their sexuality and then feel intensely ashamed if they become excited by sensations or images that recall their molestation, even when those sensations are the natural pleasures associated with particular body parts. If trauma survivors are forced to discuss their experiences, one person’s blood pressure may increase while another responds with the beginnings of a migraine headache. Still others may shut down emotionally and not feel any obvious changes. However, in the lab we have no problem detecting their racing hearts and the stress hormones churning through their bodies.
These reactions are irrational and largely outside people’s control. Intense and barely controllable urges and emotions make people feel crazy—and makes them feel they don’t belong to the human race. Feeling numb during birthday parties for your kids or in response to the death of loved ones makes people feel like monsters. As a result, shame becomes the dominant emotion and hiding the truth the central preoccupation.
They are rarely in touch with the origins of their alienation. That is where therapy comes in—is the beginning of bringing the emotions that were generated by trauma being able to feel, the capacity to observe oneself online. However, the bottom line is that the threat-perception system of the brain has changed, and people’s physical reactions are dictated by the imprint of the past.
The trauma that started “out there” is now played out on the battlefield of their own bodies, usually without a conscious connection between what happened back then and what is going on right now inside. The challenge is not so much learning to accept the terrible things that have happened but learning how to gain mastery over one’s internal sensations and emotions. Sensing, naming, and identifying what is going on inside is the first step to recovery.
THE SMOKE DETECTOR GOES ON OVERDRIVE
Stan’s brain scan shows his flashback in action. This is what reliving trauma looks like in the brain: the brightly lit area in the lower right-hand corner, the blanked-out lower left side, and the four symmetrical white holes around the center. (You may recognize the lit-up amygdala and the off-line left brain from the Harvard study discussed in chapter 3.) Stan’s amygdala made no distinction between past and present. It activated just as if the car crash were happening in the scanner, triggering powerful stress hormones and nervous-system responses. These were responsible for his sweating and trembling, his racing heart and elevated blood pressure: entirely normal and potentially lifesaving responses if a truck has just smashed into your car.
Imaging a flashback with fMRI. Notice how much more activity appears on the right side than on the left.
It’s important to have an efficient smoke detector: You don’t want to get caught unawares by a raging fire. But if you go into a frenzy every time you smell smoke, it becomes intensely disruptive. Yes, you need to detect whether somebody is getting upset with you, but if your amygdala goes into overdrive, you may become chronically scared that people hate you, or you may feel like they are out to get you.
THE TIMEKEEPER COLLAPSES
Both Stan and Ute had become hypersensitive and irritable after the accident, suggesting that their prefrontal cortex was struggling to maintain control in the face of stress. Stan’s flashback precipitated a more extreme reaction.
The two white areas in the front of the brain (on top in the picture) are the right and left dorsolateral prefrontal cortex. When those areas are deactivated, people lose their sense of time and become trapped in the moment, without a sense of past, present, or future.16
Two brain systems are relevant for the mental processing of trauma: those dealing with emotional intensity and context. Emotional intensity is defined by the smoke alarm, the amygdala, and its counterweight, the watchtower, the medial prefrontal cortex. The context and meaning of an experience are determined by the system that includes the dorsolateral prefrontal cortex (DLPFC) and the hippocampus. The DLPFC is located to the side in the front brain, while the MPFC is in the center. The structures along the midline of the brain are devoted to your inner experience of yourself, those on the side are more concerned with your relationship with your surroundings.
The DLPFC tells us how our present experience relates to the past and how it may affect the future—you can think of it as the timekeeper of the brain. Knowing that whatever is happening is finite and will sooner or later come to an end makes most experiences tolerable. The opposite is also true—situations become intolerable if they feel interminable. Most of us know from sad personal experience that terrible grief is typically accompanied by the sense that this wretched state will last forever, and that we will never get over our loss. Trauma is the ultimate experience of “this will last forever.”
Stan’s scan reveals why people can recover from trauma only when the brain structures that were knocked out during the original experience—which is why the event registered in the brain as trauma in the first place—are fully online. Visiting the past in therapy should be done while people are, biologically speaking, firmly rooted in the present and feeling as calm, safe, and grounded as possible. (“Grounded” means that you can feel your butt in your chair, see the light coming through the window, feel the tension in your calves, and hear the wind stirring the tree outside.) Being anchored in the present while revisiting the trauma opens the possibility of deeply knowing that the terrible events belong to the past. For that to happen, the brain’s watchtower, cook, and timekeeper need to be online. Therapy won’t work as long as people keep being pulled back into the past.
THE THALAMUS SHUTS DOWN
Look again at the scan of Stan’s flashback, and you can see two more white holes in the lower half of the brain. These are his right and left thalamus—blanked out during the flashback as they were during the original trauma. As I’ve said, the thalamus functions as a “cook”—a relay station that collects sensations from the ears, eyes, and skin and integrates them into the soup that is our autobiographical memory. Breakdown of the thalamus explains why trauma is primarily remembered not as a story, a narrative with a beginning middle and end, but as isolated sensory imprints: images, sounds, and physical sensations that are accompanied by intense emotions, usually terror and helplessness.17
In normal circumstances the thalamus also acts as a filter or gatekeeper. This makes it a central component of attention, concentration, and new learning—all of which are compromised by trauma. As you sit here reading, you may hear music in the background or traffic r
umbling by or feel a faint gnawing in your stomach telling you it’s time for a snack. If you are able to stay focused on this page, your thalamus is helping you distinguish between sensory information that is relevant and information that you can safely ignore. In chapter 19, on neurofeedback, I’ll discuss some of the tests we use to measure how well this gating system works, as well as ways to strengthen it.
People with PTSD have their floodgates wide open. Lacking a filter, they are on constant sensory overload. In order to cope, they try to shut themselves down and develop tunnel vision and hyperfocus. If they can’t shut down naturally, they may enlist drugs or alcohol to block out the world. The tragedy is that the price of closing down includes filtering out sources of pleasure and joy, as well.
DEPERSONALIZATION: SPLIT OFF FROM THE SELF
Let’s now look at Ute’s experience in the scanner. Not all people react to trauma in exactly the same way, but in this case the difference is particularly dramatic, since Ute was sitting right next to Stan in the wrecked car. She responded to her trauma script by going numb: Her mind went blank, and nearly every area of her brain showed markedly decreased activity. Her heart rate and blood pressure didn’t elevate. When asked how she’d felt during the scan, she replied: “I felt just like I felt at the time of the accident: I felt nothing.”
Blanking out (dissociation) in response to being reminded of past trauma. In this case almost every area of the brain has decreased activation, interfering with thinking, focus, and orientation.
The medical term for Ute’s response is depersonalization.18 Anyone who deals with traumatized men, women, or children is sooner or later confronted with blank stares and absent minds, the outward manifestation of the biological freeze reaction. Depersonalization is one symptom of the massive dissociation created by trauma. Stan’s flashbacks came from his thwarted efforts to escape the crash—cued by the script, all his dissociated, fragmented sensations and emotions roared back into the present. But instead of struggling to escape, Ute had dissociated her fear and felt nothing.
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