When Todd was five, the neighbor’s cat went ballistic and gave him a really bad scratch. Twenty years later, Todd still steers clear of cats. In fact, his brain’s (which is involved in emotion and fear) lights up, and Todd starts to sweat and feel anxious, if someone even mentions cats.
Can Todd train his brain to react differently? But now Todd has fallen in love with a woman who owns several cats and can’t imagine her life without her feline friends.
For years, people have sought relief from fearful or painful memories by exploring them in the safety of a psychologist’s office. There’s something about activating the regions of the brain involved in those memories—in settings where the anticipated outcome never materializes—that creates new associations. In other words, if Todd racks up enough scratch-free experiences talking about cats in the safety of a counselor’s office, seeing cats safely from a distance, or petting cats without consequence, the link Todd’s brain makes between cats and scratches will begin to weaken.
Scientists are figuring out a new way to desensitize the brain through these kinds of repeated, pain-free exposures. And they’re doing it during sleep.
Researchers created fearful memories by delivering mild electric shocks to study participants at the same time theparticipants were shown pictures of faces and exposed to distinct scents, like lemon or mint. Pretty soon, all it took was seeing the pictures and smelling the scent and participants would break out in a slight sweat, their amygdalas on alert, anticipating the mild shock.
After training the brain to respond fearfully to certain images and smells, could researchers retrain the brain? Could they desensitize those memories? Create pain-free associations that would begin to diffuse the painful associations they had fostered? Even more intriguing, could they create pain-free associations while the participants were asleep?
They managed to do just that, and they accomplished it by having participants nap in the lab with electrodes on their scalps to monitor brain waves. During slow-wave sleep, when recent memories are most active, researchers repeatedly exposed the nappers to the same scents—lemon and mint—this time without any shocks.
At first, even while sleeping, participants responded the same way they had when they were awake, by sweating and with brain activity that indicated the same kind of negative anticipation. Before long, however, with repeated exposures, the volunteers began to show less negative reactions both in their bodies and their brains.
People who slept longer and received more “safe” exposures benefited the most from the treatment.
After waking up, participants continued to show decreased responses to the photos and scents, meaning the desensitization they demonstrated while sleeping stuck with them.
Will nap therapy replace talk therapy in the near future? Probably not. Although if the two approaches are ever combined, time spent on your psychologist’s couch might mean bringing along a pillow, as well.