Every educator or parent who’s wondered what’s going on in the heads of moody, socially obsessed teenagers may soon get an answer. The National Institutes of Health will dedicate $300 million over the next decade to launch the largest, most comprehensive study to date of how children’s brains develop during adolescence.
The Adolescent Brain Cognitive Development study, or ABCD, will bring together researchers from nearly two dozen institutions across the country to track the development of 10,000 children, ages 9 and 10, over the next decade.
The project will be the largest longitudinal study to use regular magnetic resonance imaging scans, or MRIs, to track how students’ brain structure and activity changes as they grow, and compare those changes to measures of mental health, academic and social progress and engagement, and risky behaviors, such as drug and alcohol use.
For the most part, studies of adolescents have compared brain images of different groups of children, teenagers, and adults to identify changes over time, rather than following a representative group of students as they grow.
“Until not too long ago, people thought the development of the human brain was essentially accomplished in the first few years [of life]. However, it’s become clearer and clearer that the cognitive development of the brain is very protracted,” said Terry L. Jernigan, a University of California, San Diego, professor of cognitive science, psychiatry, and radiology and the director of the university’s Center for Human Development. “We have the potential to gain a lot of critical insight into this time of the developing mind.”
Jernigan will lead the project’s coordinating center with UCSD psychology professor Sandra Brown.
Emerging Picture
Adolescence is a vulnerable transition from childhood to adulthood. Teenagers are the age group most likely to die from accidental injuries, like car crashes, and are those at highest risk for the development of serious mental illnesses like schizophrenia and depression. And anyone who remembers middle and high school knows that the bewildering mix of raging hormones and shifting social circles can play havoc on students’ academic development.
But emerging research suggests adolescence is also a critical time for the development of complex problem-solving and social learning.
“We do recognize more and more that this adolescent period does have some unique characteristics in terms of how emotional functions, motivation, and reward functions are changing,” Jernigan said. “They play a large role in what kids are attracted to and what they avoid and how well they negotiate their entry into young adulthood.”
For example, studies have found that adolescents have higher activation in areas of the brain associated with social connections, such as the dorsomedial prefrontal cortex, than either children or adults. A series of studies by University of California, Los Angeles, neuroscientist Matthew Lieberman found that teenagers assigned to learn a gambling card game picked up strategies more quickly and performed better when they played with three others of the same age than they did when they played the game only against a computer.
“One of the things emerging from neuroscience has been our growing understanding of what represents a rewarding experience for adolescents and how our brains mediate reward or loss,” Jernigan said. For adolescents to be deeply engaged in a task, “people have to be able to make progress, see that progress as they are making it, and have some challenge and uncertainty to it. And that immediate feedback and progress is very engaging to them.”
The study will also provide more nuanced insight into how drugs affect teenagers and why prior studies have shown that people who begin using drugs or alcohol during adolescence are at greater risk of severe addiction.
“Adolescents have access to high-potency marijuana and greater varieties of nicotine-delivery devices than previous generations,” said Nora Volkow, the director of the National Institute on Drug Abuse, part of the NIH, in a statement. “We want to know how that and other trends affect the trajectory of the developing brain.”
For example, some studies have found teenagers use different patterns of thought to perform a task involving self-control than adults do, in ways that might make them more vulnerable to the effects of addictive drugs.
In one study presented at the Society for Neuroscience meeting here last week, Georgia O’Callaghan, a researcher at Trinity College in Ireland, compared brain activity in older adolescent and adult male drivers as they took several tests of self-control and the ability to gauge risk and rewards.
Risk-Taking and Self-Control
While both older and younger drivers performed equally accurately, O’Callaghan found that young drivers had different patterns of processing the self-control task than older drivers, particularly if they had a history of unsafe driving.
Researchers for 13 initial study sites met last week at the Society for Neuroscience meeting to plan the first five years of projects. They also plan to partner with schools and districts to identify critical questions to study.
“A set of experiences that seem to be relatively devastating to one child can be strengthening to another,” Jernigan said.
“It’s not likely we can define an optimal set of experiences or curriculum for every child to have,” she said. “We have to learn better to match the interventions we have available to children when things go awry.”
