Excerpted fromExtreme Fear

by Jeff Wise. Copyright © 2009 by the author and reprinted by permission of Palgrave Macmillan, a division of Macmillan Publishers Limited. All rights reserved.

This excerpt is a sample from DISCOVER's special Brain issue, available only on newsstands through June 28.

In the throes of intense fear, we suddenly find ourselves operating in a different and unexpected way. The psychological tools that we normally use to navigate the world—reasoning and planning before we act—get progressively shut down. In the grip of the brain’s subconscious fear centers, we behave in ways that to our rational mind seem nonsensical or worse. We might respond automatically, with preprogrammed motor routines, or simply melt down. We lose control.

In this unfamiliar realm, it can seem like we’re in the grip of utter chaos. But although the preconscious fear centers of the brain are not capable of deliberation and reason, they do have their own logic, a simplified suite of responses keyed to the nature of the threat at hand. There is a structure to panic.

When the danger is far away, or at least not immediately imminent, the instinct is to freeze. When danger is approaching, the impulse is to run away. When escape is impossible, the response is to fight back. And when struggling is futile, the animal will become immobilized in the grip of fright. Although it doesn’t slide quite as smoothly off the tongue, a more accurate description than “fight or flight” would be “fight, freeze, flight, or fright”—or, for short, “the four fs.”

On a winter morning a few years back, a young woman named Sue Yellowtail went through them all in about 10 minutes.

FREEZEThe Mancos River rises in southwestern Colorado and flows through the Ute Mountains on its way to New Mexico, where it empties into the San Juan River three miles shy of the Four Corners intersection. Over millions of years, the river and its tributaries have carved a fanlike rill of dramatic canyons out of the ancient sediments of the Mesa Verde tablelands, a maze of vertiginous stone walls. The rugged, arid landscape of juniper forest proves a rich habitat for wildlife.

At 25, Sue Yellowtail was just a few years out of college, working for the Ute Indian tribe as a water quality specialist. Her job was to travel through remote areas of the Ute reservation, collecting samples from streams, creeks, and rivers. She spent her days crisscrossing remote backcountry, territory closed to visitors and rarely traveled even by locals. It’s the kind of place where, if you got in trouble, you were on your own.

On a clear, cold morning in late December, Yellowtail pulled her pickup over to the side of a little-used dirt double-track, a few yards from a simple truss bridge that spanned a creek. As she collected her gear, she heard a high-pitched scream. Probably a coyote killing a rabbit, she thought. She clambered down two steep embankments to the water’s edge. Wading to the far side of the creek, she stooped to stretch her tape measure the width of the flow. Just then she heard a rustling and looked up. At the top of the bank, not 30 feet away, stood a mountain lion. Tawny against the brown leaves of the riverbank brush, the animal was almost perfectly camouflaged. It stared down at her, motionless.

She stood stock-still.

Yellowtail had entered the first instinctual fear-response state, the condition of freezing known as attentive immobility. Even before she was aware of danger, subconscious regions of her brain were assessing the threat. Cued to the presence of a novel stimulus, the brain deployed the orienting reflex, a cousin of the startle reflex. Within milliseconds Yellowtail’s heart rate and breathing slowed. A brain region called the superior colliculus turned her head and slewed her eyes so that the densest part of the retina, the fovea, formed a detailed image of the cat. The visual information then flowed via the thalamus to the visual cortex and the amygdala, the key brain center for evaluating threat. Her pattern-recognition system found a match in the flow of sensory information. It recognized a pair of eyes, then the outline of a feline head. In less than half a second, before her cortex even had time to complete the match and recognize what she was seeing, her emotional circuitry had already assessed the situation: It was bad. Subconsciously, her brain also determined that the threat was not immediately pressing, and so a region called the ventral column of the periaqueductal gray (PAG) triggered attentive immobility. This is generally considered the first stage of the fear response, because it tends to occur when the threat is far away or not yet aware of the subject’s presence. The goal is to keep it that way.

When a person is frozen with fear, she is motionless but far from passive. With cortisol and adrenaline coursing through her body, she is primed for physical action, alert and intensely focused. The heart rate slows and blood pressure shoots up. Muscles tense and the pupils dilate. The body may tremble and the eyes bulge. If the fear is intense, the mind might be plunged into a state called hypervigilance, in which a person scans the environment rapidly and randomly, unable to think through the available options clearly.

Freezing is a posture of an animal that, while in danger, is primarily concerned with not getting in worse danger. Its plan is to do nothing, hope to avoid being detected, and see what happens. In the natural environment, it often proves an effective strategy. Young antelope can spend the better part of the day lying crouched and motionless in tall grass, their ears tucked and heads pressed against the ground. When accidentally disturbed by a passing lion or hyena, they bolt so unexpectedly that the predator may be too startled to chase after them.

Yellowtail’s was just the kind of situation that the behavior had evolved for: eluding a nearby predator. But freezing is essentially a temporary measure, a stopgap until the danger either goes away or becomes more pressing. It is a posture that asks the question: What next?

In the morning light of Mancos Canyon, human and animal stood confronting each other. Yellowtail had never seen a mountain lion in the wild before. Even as she fought to contain her fear, she marveled at the beauty of it. Its dark eyes looked back at her. Who knew what it was thinking behind that gaze. Was it curious, or hungry?

FLIGHTAs she locked eyes with it, the mountain lion moved forward, descending the shrubby bank and heading straight toward her.

Yellowtail waded back across the three-foot-deep stream, back toward her truck. To be prudent, she thought, she had better keep the width of the icy stream between herself and the animal. As she made it to the far side, the big cat quietly slipped into the water.

A former biology major, Yellowtail had studied predator behavior. She knew that if she began climbing the steep bank up toward her truck, she would expose her back, and she guessed that the moment of vulnerability might spur the mountain lion to attack. Instead she moved quickly down the edge of the stream and crossed again, feeling her way over the slick cobbles underfoot. Looking behind her, she expected to see the animal climb the far bank and disappear. But no: It followed her path along the water’s edge and again started swimming after her.

“I’m in trouble,” Yellowtail thought. “This is serious.” There was no doubting the mountain lion’s intention now. Trapped between the stream’s steep narrow banks, she couldn’t think of any way to keep the animal away. She was holding a microcassette recorder that she kept for taking notes, and she threw it at the cat. It just kept coming.

Yellowtail retreated down the riverbank, shouting and throwing rocks and chunks of ice. Somehow she managed to keep herself from running. She crossed the stream, worked farther down the bank, and crossed again. The cat followed, relentlessly closing the distance. Even as she felt panic building, Yellowtail had enough presence of mind to understand that what she was seeing was a classic example of predator behavior. Running would only stoke the animal’s attack instinct. She had to fight the urge.

The mountain lion was close now, near enough to pounce. As she splashed once more across the stream, the need to run surged over her like a shiver. She bolted, splashing madly through the shallow water, her legs churning over the rough, slippery cobbles of the streambed.

She ran with everything she had.

Yellowtail was now in the grip of the second phase of the fear response, flight. The sudden movement of the mountain lion had broken the spell of her attentive immobility and gotten her moving, but while the animal was still a fair distance off she had managed to keep her wits and suppress her fear centers’ automatic panic reaction. But as the cat drew closer, reason and willpower wavered as the fear grew stronger. At last they gave way altogether.

This process has been witnessed in the laboratory using brain-scan technology. Subjects inside an fMRI scanner were asked to play a Pacman-like game in which they were chased by a predator. When they were “caught,” they were given a series of mild electric shocks. While not exactly a realistic scenario, the game did elicit brain activity that paralleled Yellowtail’s. When the “predator” was far away, the subjects’ brains showed activity mostly in the prefrontal cortex. As it drew nearer, the area of greatest metabolism shifted to the periaqueductal gray, the region that codes for the behavioral patterns of the four fs.

Yellowtail made it only halfway across the creek before her rubber boot caught on a large rock. She stumbled, twisting, and went down hard into the water. At that instant the mountain lion pounced. Instinctively it lunged for Yellowtail’s neck, but as she fell it misjudged and dragged its teeth across her scalp. Under the weight of the big cat, Yellowtail slipped below the surface.

FRIGHTLooking back on the moment from years after the fact, Yellowtail can still recall every detail with perfect clarity. She remembers feeling the warmth of the animal’s mouth on her head. She remembers looking up toward the surface through her sunglasses and thinking, with a perplexing degree of calm: “When your time’s up, your time’s up.”

Yellowtail had entered a third phase of the fear response, a state known as tonic immobility, or quiescence—in lay terms, playing possum. When an animal is seized by an attacker, the caudal ventrolateral region of the PAG generates a response that from the outside looks like total collapse. In the teeth of a full-blown sympathetic response, the parasympathetic system now swings into overdrive. The body, insensitive to pain, goes completely limp, often falling to the ground as awkwardly as rag doll, limbs splayed, head thrown back. Eyes closed, it trembles, defecates, and lies still. It looks, in a word, dead.

This is the position of utter despair, a final, last-ditch Hail Mary pass of a strategy. The one hope of quiescence is that the attacker, thinking its quarry has expired, will stop attacking. In Yellowtail’s case, the mountain lion appeared to react to her quiescence. Momentarily it released its grip. That was enough. In an instant she snapped out of her dissociative dream state and was sputtering back up to the air. Without reason, without thought, she started running again, flailing so hard that she ran right out of one of her hip boots.

And then—nothing. Whatever happened next, Yellowtail has no idea, because for the next 10 or 15 seconds she was overcome by a panic so blind that she blacked out. She had entered a realm of fear strong enough to shut down the memory-forming hippocampus and perhaps even consciousness itself.

The science behind that kind of amnesia remains murky, because such intense fear is a state as yet inaccessible to science. It is known that amnesia often accompanies extremely terrifying experiences. Chances are, an overdose of cortisol or a related substance, corticosterone, disrupts the hippocampus and inhibits the formation of new memories. This could be beneficial if it prevents later traumatic recollections.

Yellowtail will never know what terror her amnesia cloaked. At any rate, it did not last long. The next thing she remembers, she was on the riverbank on the far side of the stream. She had emerged from her blind panic oddly collected and remembers that time seemed to be moving in slow motion. She found herself lying on top of the mountain lion’s shoulders, her right arm thrust down its throat. She looked down and saw that the animal’s jaws were so huge that its canines were overlapped on either side of her arm.

NEXT: THE SHOWDOWN

FIGHT“I’ve got to kill this animal or it’s going to kill me,” she thought. She happened to be wearing her fly fishing vest, from which hung a surgical-steel hemostat on a retractable string. In the strange clarity of total fear, she reasoned through a course of action. First she tried to wrap the string around the cat’s throat to strangle it but abandoned that plan when the cat thrashed, slashing its teeth dangerously close to her fingers. Before moving on to a new strategy, she paused and carefully inspected her left hand to make sure her fingers were all there. “Because if they weren’t, I was going to pick them up and put them in my pocket,” she says today. “It’s just crazy, the stuff that you think about.”

Her next thought was to stab it in the eye with the hemostat. “It just dawned on me: ‘I’ve got to get to the brain,’ so the eye was the best bet.” Without thinking twice, she clutched the hemostat and stabbed it over and over again into the cat’s left eye. The beast screamed a horrifying yowl. She kept stabbing.

Yellowtail had worked her way through to the last of the four fs, the fight, or aggressive defense, response. Like quiescence, aggressive defense is a tactic of last resort. People in the throes of full sympathetic overdrive are capable of totally uninhibited, blind violence. They will use any weapon and inflict any injury they can. On the battlefield this impulse may be useful in the heat of fighting, but it can also lead to reckless, even mindless, behavior. And it is very difficult to shut off. Once the cortex has yielded control to the PAG, there is no getting it back until the shouting is over. The annals of military history are filled with tales of soldiers who kept slaughtering well after the battle was over.

In Yellowtail’s case, there was no need to restrain her impulse to violence. After a while, though, she sensed that the mountain lion had had enough. She kicked off her other hip boot and got ready to stand up. The cat let go of her arm. As soon as Yellowtail’s weight was off it, the cat stood up too. Yellowtail lunged at it, swearing and shouting, “Come on, you want some more?” The cat didn’t move. Yellowtail lunged again, to see if it seemed ready to attack her again. It just stood there, looking dazed. Yellowtail backed up about 20 feet, then turned and ran down the bank until she found a cattle path through the brush leading back up the embankment to the road, and then to her truck. “The whole time, I was worried that she was going to come through the brush and get me,” Yellowtail says, “but she never did.”

Yellowtail got into her truck and drove for help. Not until she was in an ambulance did her multiple cuts and bruises begin to throb with pain. Trackers returned to the site of the attack, located the mountain lion, and shot it. It turned out to be an aged female, underweight and weak from starvation. Yellow­tail figures that if the cat had been a full-size male, she would be dead now. As it was, she came very close.

“It’s amazing what you can do when you’re under that kind of stress, in a life-or-death situation,” she says. “You do whatever it takes to keep yourself alive.”

Excerpted fromExtreme Fear

by Jeff Wise. Copyright © 2009 by the author and reprinted by permission of Palgrave Macmillan, a division of Macmillan Publishers Limited. All rights reserved.

This excerpt is a sample from DISCOVER's special Brain issue, available only on newsstands through June 28.