how adolescent brains literally rewire themselves before early adulthood

We know that teenagers think differently from adults because their brains aren't finished forming. But how does an adolescent brain transform into an adult one?

At this point, it's common knowledge that teenage brains take a while to mature, usually up until the age of 25, the process puts them at greater risk of mental illness as their minds quite literally rewire themselves, and they have poor impulse control because they can't accurately judge the consequences of their actions. It's also hardly a revelation that adolescents are often more self-involved than adults. So, what happens when egocentric teenagers become well-adjusted and empathetic, at least to some degree, adults? Is it just experience and enough well-meaning instruction from good role models? Well, yes and no. Guidance can play a positive role, but the mechanics of the brain itself are vital to complete the process.

According to a new study which looked at the brain activity of nearly 300 healthy teenagers and young adults ranging from 13 to 25, there were two major changes with age. First, regions that play key roles in coordination, vision, and hearing underwent extensive reinforcement. At the same time, regions associated with high level cognitive tasks and empathetic impulses more or less reshuffled around completely. Weak networks in these parts of the brain strengthened as previously strong connections unwound. These changes, to paraphrase the researchers, bring new neural networks online in adolescent minds, which is how they can manifest as capabilities required to become a fully functioning modern adult.

Seeing all those changes also gave the investigators another thought. If the brain is reshuffling for years on end, can some of the connections breaking down and building up explain why we see elevated risks of mental illness in teenagers? They didn't look into this -- in fact their goal was to get as calm and high resolution look at the humdrum functions of the adolescent brain as possible, which is why all the study participants were at rest while their minds were being scanned -- but armed with this new information, they're hopeful further analysis will find new and promising cues for research in that area. The hope is that the more we learn about how our brain changes with age, the better we can help maintain our mental health and acuity.

See: Váša, F., et al. (2020) Conservative and disruptive modes of adolescent change in human brain functional connectivity, PNAS, DOI: 10.1073/pnas.1906144117