Where Fear Lives

Forget about zombies, paranormal possession or the Greek economy.  If you want to know terror, you must travel deep inside the brain to the almond-shaped region known as the amygdala.

That is where fear lives.

Technically, it’s one of the parts of the brain that processes memory and emotional responses. In that capacity, it’s been front and center in two of the odder brain studies done in the past year—one concluding that conservatives have larger amygdalas than liberals, seemingly backing up previous research finding that those leaning right are more likely to respond to threatening situations with aggression. The second study, reported this month, found a correlation between the number of Facebook friends a person has and the size of his amygdala. (Don’t get the idea, though, that you can bulk up that part of your brain by friending anyone who can pronounce your name; the researchers aren’t sure what the relationship, assuming it’s widespread, really means.)

The fear factor, though, is what really intrigues scientists about the amygdala. It not only helps register our scary memories, but also controls our response to them. Research released this summer helped to explain why particularly frightening experiences create such strong memories.  In stressful situations, according to the study from the University of California at Berkeley, the amygdala induces the hippocampus—another part of the brain important for memory—to create new neurons.  These neurons become a kind of blank slate, where a particularly strong imprint can be made of a fearful memory.

Even more revealing is the case of a woman with a very rare condition that has deteriorated her amygdala, and with it, her sense of fear. She’s apparently not afraid of anything—not scary movies or haunted houses, not spiders or snakes. (She told researchers she didn’t like snakes, but when they took her to a pet store, she couldn’t keep her hands off them.) And the stories she shared in a diary showed she routinely put herself in situations the rest of us would do anything to avoid.

Post-traumatic stress

The more scientists learn about how the amyglada creates and stores memories, the better their chances of erasing bad ones. They’ve discovered, for instance, that memories aren’t locked in forever. Instead, each time an experience arouses a fear, the memory associated with it is revived and is actually open to manipulation. That window of opportunity to change a memory through therapy apparently can  stay open as long as six hours. It also could close within an hour.

No question that the need to deal more aggressively with fear is being driven by the surge in victims of post-traumatic stress disorder (PTSD). It’s estimated that at least one out of five people who have served in Iraq or Afghanistan—or roughly 300,000 veterans—have been diagnosed with it. A number of therapeutic approaches have emerged, including a promising small-scale program that combines medical treatment and counseling in a residential setting.

Some scientists think the key to defusing terrifying memories is to deal with them within hours of a trauma, that there’s a “golden hour” for treating victims most effectively, much like there is for heart attacks and strokes. Two Israeli researchers say their studies show that giving patients Valium or Xanax to calm them down after trauma actually increases the likelihood of them developing PTSD, whereas a shot of cortisone, they contend, can decrease it by as much as 60 percent.

Others say more research is needed on drugs such as propranolol, best known as a treatment for high blood pressure, but a medication that also seems to defang traumatic memories. Still other scientists say they have evidence that MDMA, the active agent in the party drug ecstasy, and marijuana have a lot of potential as a long-term PTSD treatment, although some advocates claim that research on the latter has been stalled by the National Institute on Drug Abuse.

Probably the most innovative approach to confronting the demons of PTSD involves 3D goggles. This month the Army kicked in $500,000 for a pilot project to train PTSD victims in something the military’s calling “Power Dreaming.” The treatment, rolling out at the Naval Hospital Bremerton in Washington State next year, would work like this: A veteran who wakes from a stress nightmare reaches for the 3D glasses. He or she is transported to a soothing virtual world, one  filled with images that relax them. 

Bonus  fear: It may not be as traumatic as PTSD, but fear of math is the real deal. A new study published in Cerebral Cortex has brain scans to back it up. 

Randy Rieland | | READ MORE

Randy Rieland is a digital media strategist and contributing writer in innovations for Smithsonian.com.