Vulnerabilities and Opportunities: New Insights Into the Adolescent Brain

by Kayt Sukel

March 8, 2012

Like many teenagers, I got into my fair share of scrapes as I grew into my adult mind and body. Often, my father’s response to my youthful misfortune was to ask, “What were you thinking? Were you even thinking at all?” While there is a pervasive notion that the teenage brain is immature and not working up to its true potential, new research in the field of neuroscience is discovering that adolescence offers more than just cognitive vulnerabilities. Instead, researchers are demonstrating that these vulnerabilities are paired with great opportunities for growing, learning, and perhaps even preventing later psychiatric illness.

Understanding the teenage brain

Adolescence is a time of great change, both in body and brain—and anyone who has ever watched their child go through adolescence knows that those changes occur fairly quickly.

“We’re finally getting our adult minds around the fact that adolescence is a time when everything explodes, physically and neurally,” says Abigail Baird, a researcher at Vassar College and a member of the Dana Alliance for Brain Initiatives. “We see that explosive growth and the gawkiness on the outside—kids shooting up with long, clumsy arms and legs. But there’s that same gawkiness in the brain, too. Everything is changing and it’s changing really, really fast.”

Baird says that while it is easy to simply downplay this “neural gawkiness” as a period of immaturity that parents, scientists and policy makers could ignore until it goes away (likely praying, “This, too, shall pass” as they do so), researchers are now starting to realize that there may be opportunity in adolescence to help children become smarter, stronger adults – and perhaps even avoid the consequences of risky behaviors and psychiatric illness.

“The biggest source of morbidity and mortality in young people, not only in the United States, but in industrialized countries, in general, are not medical diseases but problems with behavior and emotion. We’re talking about accidents, suicide, homicide, car accidents, substance abuse and sexual risk-taking,” says Ronald Dahl, a researcher of the University of California, Berkeley’s School of Public Health. “If we can understand the adolescent brain, this time of great flexibility and adjustment, we can better identify risky groups and think about policies to help teens get through this period of time and reduce the rate of terrible outcomes.”

Weighing risks and rewards

One difference noted between adult and adolescent brains is how they process risk and rewards. Recent work by B.J. Casey and colleagues at Cornell University suggests that teens understand and process risks involved with certain behaviors the same way that adults do—but adolescents tend to overestimate rewards. Areas of the brain involved with reward processing are much more active in the teenage brain than in those of children or adults.

“It makes sense. Really wanting those rewards is to our advantage when learning. One thing we do know about adolescent is that it’s a really great time to learn new things,” says Baird. “And having that incentive to get yourself up, dust yourself off and try it all over again is invaluable. Otherwise, we might not try again and get the experience we need to actually do that learning we need to move from childhood to adulthood.”

A recent study by Bita Moghaddam, a neuroscientist at the University of Pittsburgh, supports this idea—and suggests that the anticipation of a reward is very important. Using a behavioral clamping technique, Moghaddam and colleagues recorded brain activity in adult and adolescent rats during a simple learning task. They discovered a significant difference in activity in the dorsal striatum, a region of the brain linked to habit formation, action selection, and motivated learning, with higher activation seen in adolescent rats.

“It’s very interesting that this reward is directly tapping into a region that is involved with action selection and habit formation,” says Moghaddam. “So it’s possible that if you are doing something that is motivating and anticipate a reward, then that could influence behavior far more strongly in adolescents than in adults.”

Moghaddam says this finding may help us understand why adolescence is such a risk period for addiction. “If you start smoking as a teenager, the chance of you becoming a nicotine addict is very large,” she says. “This anticipation of reward may make the brain of an adolescent more vulnerable to addiction than that of a young adult.” 

Applying the findings

While my dad might have thought my teenage brain wasn’t thinking at all, current research suggests that the adolescent brain is actually working overtime, trying to sync up higher cognition systems involved with planning and inhibition with emotional and motivational circuits. But Dahl says that ideas that hormones make teenagers crazy or that teens are unable to use their frontal cortexes appropriately are unfair. “Eighty percent of adolescents don’t do wild and crazy things,” he says. “But even the shy, anxious kids tend to become more exploratory and more likely to experiment during mid- to late adolescence. It’s necessary to gain experience, to learn and to sync up these systems.”

Moghaddam believes the teen brain’s natural flexibility may provide an opportunity to intervene and prevent later psychiatric illness. She does not think it is a coincidence that disorders like depression, bi-polar disorder, schizophrenia and addiction start showing symptoms in adolescence. Baird concurs but says that there’s still a lot more we need to learn about the adolescent brain.

“The fact that so much is changing and growing in the teenage brain is actually really optimistic,” Baird says. “Because, if everything is up in the air, undecided, and still developing, imagine all the good we could do if we understood exactly how and why. We’d have this great opportunity to jump in and straighten things out where needed.”