Scientists have uncovered a unique feature of the adolescent brain that enriches teens' ability to learn and form memories: the coordinated activity of two distinct brain regions.

This observation, which stands in contrast to the adult brain, may be related to teens' oft-derided affinity for reward-seeking behavior. These findings suggest that such behavior is not necessarily detrimental, but instead may be a critical feature of adolescence and the maturing brain.

The results of this research were published in Neuron.

"Studies of the adolescent brain often focus on the negative effects of teens' reward-seeking behavior. However, we hypothesized that this tendency may be tied to better learning," said a principal investigator. "Using a combination of learning tasks and brain imaging in teens and adults, we identified patterns of brain activity in adolescents that support learning—serving to guide them successfully into adulthood."

For this study, which involved 41 teens and 31 adults, the authors initially focused on a brain region called the striatum. Previous research has shown that the striatum coordinates many aspects of higher brain function, from planning to decision making. But it is most well-known for its role in something called reinforcement learning.

Because of teens' inclination toward reward-seeking behavior, the researchers proposed that this age group would outpace adults in terms of reinforcement learning by showing a greater affinity for rewards. This hypothesis was confirmed after asking both groups to perform a series of learning tasks.

To see what was happening in the brain researchers scanned the brains of each participant with functional magnetic resonance imaging (fMRI) while they were performing the learning tasks. The authors hypothesized that the teens' superior abilities were due to a hyperactive striatum.

The authors' fMRI analysis revealed an uptick in hippocampal activity for teens—but not adults—during reinforcement learning. Moreover, that activity seemed to be tightly coordinated with activity in the striatum.

To investigate this connection, the researchers slipped in random and irrelevant pictures of objects into the learning tasks, such as a globe or a pencil. The images—which had no bearing on whether the participants guessed right or wrong—served as a kind of background noise during the tasks. When asked later on, both adults and teens remembered seeing some of the objects, but not others. However, only in the teens was the memory of the objects associated with reinforcement learning, an observation that was related to connectivity between the hippocampus and striatum in the teen brain.

Indeed, studies have shown that adolescence is a pivotal time when powerful memories are formed, which the authors argue could be due to this enhanced connectivity between the hippocampus and striatum.

http://www.cell.com/neuron/abstract/S0896-6273(16)30524-4?_returnURL=http%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0896627316305244%3Fshowall%3Dtrue