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A Unique Time, Full of Opportunity: Demystifying the Teenage Brain

Angst, love, heartbreak, and serious growing pains: whether they were over yesterday or decades ago, chances are you remember your teenage years vividly.

I am Livia, and I remember often being overwhelmed by powerful emotions, swinging like a pendulum from one to another, and confused as to why, exactly. Though memorable, the teenage experience often evokes lots of mystery.

Whilst the concept of the tricky transitional space between childhood and adulthood has been around for thousands of years, knowledge of brain development was long speculative. Experts reasoned human brains had to be completed in childhood and adolescent dispositions were consequently blamed on culture, and teenagers stereotyped as moody, self-centred, and sensation seeking creatures that were hard to understand.

But once Magnetic Resonance Imaging (MRI) — where living organs can be observed through magnetic cameras — was invented, a fresh, neuroscientific story about the teenager emerged, changing the way we see the teenage brain and the lived experience it creates.

The author as a teenager in 2015. Photo supplied by Livia Dyring.

A race car engine with bicycle brakes

Contrary to what was previously believed, the new MRI studies demonstrate that the teenage years are an enormously eventful phase: though teenagers’ brains do not grow larger, the way that the brains of young children do, they do undergo complex structural changes.

In early childhood, a fatty substance called myelin, or white matter, starts to spread across the brain and cover axons, which are wires that help connect neurons. Neurons are nerve cells that send messages through the brain and body, granting us the ability to function.

As myelin slowly expands, the various brain regions are able to transmit messages between each other faster, creating an overall better-connected system. Myelination, as the process is called, begins at the back of our brain, wrapping up at the front, by the frontal lobes, when we reach our mid-to-late twenties.

According to Dr Frances E Jensen, the fact that the frontal lobes, where the prefrontal cortex happens to be located, become the last to be myelinated is key to demystifying the teenage experience.

The prefrontal cortex is believed to play a part in executive function, a group of cognitive skills that include, for example, the capacity to control what we say, regulate what we feel, and, interestingly, to evaluate the outcomes to things we are about to do. As this handy brain region waits to be myelinated and become as powerful as it can be, however, other parts, such as the limbic system, widely thought to be important for emotion and motivation, for example, have already matured.

Teenagers, specifically, happen to be in the midst of the slow myelination process, and the discrepancy between regions that have not matured to the same level likely explains why their machinery resembles a race car with bicycle brakes: as teenagers experience emotions, they have yet to gain enough cognitive control to steer calmly through the storm.

Vulnerability and Opportunity

With myelination under way, teenagers find themselves in a period of greater neuroplasticity, meaning that the brain changes more in response to new experiences.

On the downside, the greater sensitivity of a more malleable brain makes teenagers extra vulnerable to stressors and mental health problems.

Negative emotions can be challenging without matured frontal lobes to help regulate them. In some cases, they may be exacerbated by other challenges faced by modern teenagers: a small research study suggested that teenagers’ brains may have matured sooner due to Covid-related stress, whilst a World Health Organisation report showed adolescents reported more mental health concerns during the Covid-19 lockdowns, for example. Importantly, however, the report also found that teenagers were generally resilient when supported by teachers, family, and peers.

The same neuroplasticity also gives many reasons why the turbulent teenage phase is a once-in-a-lifetime period of opportunity. The brain retains information more effectively as it matures, meaning that teenagers are allowed temporary mental perks, such as better memory and faster learning.

Parallel to myelination, the teenage brain sheds connections it no longer sees necessary, a process called specialisation: whereas children are keen to learn about everything, teenagers’ brains prune away neural connections they no longer use. Altogether, these processes make the teenage years an excellent time to shape your own identity.

A Product of Evolution

Every brain is a product of evolution, developed to help us survive, and every neurodevelopmental phase, the teenage years included, plays a critical role.

By encouraging teenagers to explore through risk-taking, the teenage brain prepares them to become grown people. Increasingly more independent, they adapt to the dynamic, uncertain time and place waiting for them — namely, the world as experienced by adults.

Many risky moves, such as declaring your love for a crush or chasing adrenaline rushes, are more often than not neurodevelopmentally healthy, as they usually reflect teenagers searching for new experience and change. Even when they do not go as planned, the bravery behind these endeavours leads to knowledge about our world — and who we can be in it.

Seen from that perspective, even an underdeveloped prefrontal cortex that promotes healthy risk-taking has a function. In fact, researchers have recently argued that both neuroscientific research and societal views have been influenced by stereotypes, and that there generally is more good than bad to teenagers’ dispositions. Now, experts focus on separating behaviours that are part and parcel of a normal teenage experience from any that could be connected to future mental health problems.

The Time of the Teenager?

Neuroscientific things considered, it may well be an exciting time to be a teenager.

As the research develops and keeps changing the old story about teenagers, society can help teenagers cope with challenges and make the most of this significant period of opportunity.

If they are supported, teenagers are perfectly placed to develop awareness, self-care tools, and healthy coping mechanisms they can rely on for lifelong mental wellbeing.

Simply learning about the teenage brain might go a long way, too; despite our many challenges, today’s teenagers are part of a lucky generation to have modern neuroscience that keeps on demystifying how brains work. I know I would have been grateful to have science reassure me when emotions overwhelmed my teenage self.

The teenage phase is thankfully temporary, but what happens then can resonate for years to come. If you had a particularly challenging time as a teenager, however, don’t fret. Thanks to the lifelong neuroplasticity of our brains, it is never too late to start mending lasting childhood wounds. Regardless how old you are, being understood — both by yourself and others — makes a world of difference.


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