Teenagers like to explore and push boundaries but not all exploration is the same. Neuroscientists have yet to fully distinguish between risk-taking, for example, as compared with strategically exploring novel experiences. A new study shows marked differences in brain activity among individual teens who are more or less exploratory. The work could help shape future interventions for treating teen substance abuse and other common behavioral conditions.
“The major goal of this study was to quantify strategic exploration using a computational model that my collaborator Michael Frank developed,” says Andrew Kayser of the University of California, San Francisco, “and to search for brain regions whose activity correlates with this exploratory behavior.”
Kayser and colleagues investigated girls near the onset of adolescence, ages 11 to 13 years old; they study girls exclusively to control for gender effects. The participants completed a number of behavioral tasks, involving trying to gain points and rewards by stopping a rotating clock, as well as an MRI scanner session. The researchers matched participants for puberty, so that they could try to distinguish age effects from puberty effects.
CNS spoke with Andrew Kayser about the study, just published in the Journal of Cognitive Neuroscience.
CNS: How did you become personally interested in this research area?
Kayser: My research interests relate to the neural basis for self regulation. I often study patient groups, and one consistent finding from the clinical literature is the increased risk for issues like substance use disorders during adolescence. Studying exploratory behaviors in this age group seemed like a good way to begin to tackle the mechanisms that explain this adolescent vulnerability.
CNS: What do you mean by strategic exploration?
Kayser: The term “strategic exploration” has to do with how we investigate novel, more uncertain rewards. It can be contrasted with random exploration, as well as with the “exploitation” of rewards we already know a lot about. In other words, strategic exploration is based on experience. If I know a lot about one thing that I like (e.g. playing soccer), but very little about another (e.g. playing basketball), I might use that information to intentionally (strategically) explore the thing I know less about.
CNS: What have we known previously about exploration in adolescence?
Kayser: It’s been relatively understudied. There is a general consensus that exploratory behavior increases in adolescence, but its neural basis remains somewhat unknown.
CNS: What were your most excited or surprised to find?
Kayser: One surprising result was that our adolescent subjects were actually somewhat more risk-averse than the adults who previously completed this task. In particular, the adolescents preferred small but high-frequency rewards, even when lower frequency rewards were of proportionally greater value. We also found that when we divided the group into explorers and non-explorers, exploratory behavior correlated with a connection from the rostrolateral prefrontal cortex to reward and risk-sensitive regions, even though that part of the cortex – thought to be important for setting and keeping track of goals – is thought not to be fully developed until late adolescence or early adulthood.
CNS: How does this work fit in with related past work on adolescence?
Kayser: In general, this finding confirms previous results that, especially at the onset of adolescence, risk-taking is not markedly increased. In addition, it is consistent with previous reports that even though rostrolateral prefrontal cortex is still developing at the onset of adolescence, it is strongly engaged in higher-order cognitive processes.
CNS: What is the takeaway message you most want people to understand about this work?
Kayser: In the big picture, this research emphasizes that the behaviors we see in adolescents have a neural correlate. To better understand how to help adolescents when behavior becomes problematic, understanding the brain mechanisms that contribute to such behavior will be critical to designing therapies.
CNS: What’s next for this line of work?
Kayser: Our next steps are to collect longitudinal data for these subjects, to further analyze data that we have collected on the task for boys, and to understand other forms of risk-taking in these subjects. Ultimately, we hope to gain a better understanding for how exploratory and risky behaviors influence the development of conditions that can impact lifelong functioning, both negatively (such as substance use disorders) and positively.
-Lisa M.P. Munoz