What part of the brain develops in your 20s?

The human brain doesn't stop developing at adolescence, but continues well into our 20s, demonstrates recent research from the Faculty of Medicine & Dentistry at the University of Alberta.

It has been a long-held belief in medical communities that the human brain stopped developing in adolescence. But now there is evidence that this is in fact not the case, thanks to medical research conducted in the Department of Biomedical Engineering by researcher Christian Beaulieu, an Alberta Innovates -- Health Solutions scientist, and by his PhD student at the time, Catherine Lebel. Lebel recently moved to the United States to work at UCLA, where she is a post-doctoral fellow working with an expert in brain-imaging research.

"This is the first long-range study, using a type of imaging that looks at brain wiring, to show that in the white matter there are still structural changes happening during young adulthood," says Lebel. "The white matter is the wiring of the brain; it connects different regions to facilitate cognitive abilities. So the connections are strengthening as we age in young adulthood."

The duo recently published their findings in the Journal of Neuroscience. For their research they used magnetic resonance imaging or MRIs to scan the brains of 103 healthy people between the ages of five and 32. Each study subject was scanned at least twice, with a total of 221 scans being conducted overall. The study demonstrated that parts of the brain continue to develop post-adolescence within individual subjects.

The research results revealed that young adult brains were continuing to develop wiring to the frontal lobe; tracts responsible for complex cognitive tasks such as inhibition, high-level functioning and attention. The researchers speculated in their article that this may be due to a plethora of life experiences in young adulthood such as pursing post-secondary education, starting a career, independence and developing new social and family relationships.

An important observation the researchers made when reviewing the brain-imaging scan results was that in some people, several tracts showed reductions in white matter integrity over time, which is associated with the brain degrading. The researchers speculated in their article that this observation needs to be further studied because it may provide a better understanding of the relationship between psychiatric disorders and brain structure. These disorders typically develop in adolescence or young adulthood.

"What's interesting is a lot of psychiatric illness and other disorders emerge during adolescence, so some of the thought might be if certain tracts start to degenerate too soon, it may not be responsible for these disorders, but it may be one of the factors that makes someone more susceptible to developing these disorders," says Beaulieu.

"It's nice to provide insight into what the brain is doing in a healthy control population and then use that as a springboard so others can ask questions about how different clinical disorders like psychiatric disease and neurological disease may be linked to brain structure as the brain progresses with age."

The research conducted by Beaulieu and Lebel was funded by the Canadian Institutes of Health Research and the Canadian Language and Literacy Research Network (CLLRNet).

Even though your teen is now as tall as you are it doesn’t mean that they have fully matured. Even though your teen may score high on the SAT or the ACT, it’s important to remember that a teen’s brain is still under development. In fact, if your child is a teenager, then you can bet that parts of their brain still need to grow and mature. For instance, there are obvious differences between the brains of adults and adolescents indicating that change, maturity, and transformation are still underway in teens.

The Pre-Frontal Cortex

One of the biggest differences researchers have found between adults and adolescents is the pre-frontal cortex. This part of the brain is still developing in teens and doesn’t complete its growth until approximately early to mid 20’s. The prefrontal cortex performs reasoning, planning, judgment, and impulse control, necessities for being an adult. Without the fully development prefrontal cortex, a teen might make poor decisions and lack the inability to discern whether a situation is safe. Teens tend to experiment with risky behavior and don’t fully recognize the consequences of their choices.

On the other hand, in adults, the frontal cortex is completely developed. They are able to process and organize information. Adults, who are emotionally and psychologically healthy, are able to judge risky behavior and factor into decision-making the consequences of their choices. Teens might rely more on their amygdala, the part of the brain dealing with emotions, whereas adults rely more on their frontal cortex, leading to balanced thinking and behavior.  In fact, another part of the brain that is still developing are certain neural networks of brain cells that link the prefrontal cortex to regions of the brain that are less about reasoning and thinking and more about emotion.

Healthy Neural Networks in Teens

Another essential part of a developing brain is the network of neurons. This large network in the brain allows cells to communicate with one another, carrying signals back and forth between the brain and the rest of the body. Research points to the fact that a healthy mind means the ability for that network of neurons to change.

As a teen grows and learns, neurons form connections that can last a lifetime. However, a healthy brain is one that can be plastic, adaptable, and continue to change with its environment. The adolescent brain is undergoing incredible growth. Neurons are wiring and new connections between the two hemispheres of the brain are forming.  This kind of growth and connection is an explosive time during adolescence. If the brain can continue to be plastic, that is if new neural connections can continue to form and if old ones can be released, this is can support healthy brain function and even a teen’s mental health. These neural connections and adaptability are important in an adolescent’s learning, behavior, and mood regulation. If a teen’s brain forms connections that support their mental health, these neural connections will then carry into adulthood support their psychological well being throughout the lifespan.

Factors that Influence a Teen’s Brain

There are some environmental and genetic factors that can affect a teen’s brain development and overall health. In fact, certain factors can contribute to mental illness, such as addiction or a psychological disorder. These factors can include:

Drug Use: Certain drugs can have severe impact on the functioning of the brain. For instance, the rush of dopamine that cocaine releases can lead to permanent alterations in the way the brain processes dopamine in the future.  According to research, this also means that because of these permanent changes in the way a teen responds to dopamine, they may be more vulnerable to cocaine addiction later in the life as well as addiction to other drugs that stimulate the release of dopamine.

Genetics: Researchers are beginning to see that shapes of certain parts of the brain are different among those who have certain mental illness, such as Bipolar Disorder for instance, versus those who don’t. Another example is the way that the amygdala functions differently in those that have mental illness. Certain genes can be passed down that affect the functioning and health of the brain and a teen brain. Of course, that doesn’t mean that a teen may develop mental illness, but it does mean that they may be vulnerable to it more so than others.

Trauma: Another way that a teen’s brain functioning and healthy may be affected is through experience. In fact, experience influences all brains, whether a teen or adult. However, traumatic experiences can have a significant impact on a teen’s brain development. Trauma often creates anxiety and fear which in turn can stifle the creativity and explosive growth that is happening in the teen brain.

Certain conditions, such as those mentioned above, can be dangerous to the developing teenage brain. Researchers have found that the way a teen’s brain functions has a significant role in the quality of health, both physical and psychological. Research continues to investigate this relationship in order to better the understanding and treatment of mental illness.

What Parents Can Do

If you’re trying to make sense of it all and doing your best to support your teen’s growth, here are a few suggestions to consider:

Discuss pros and cons with your teen. When your teen comes to you with a problem, help your teen identify the consequences or results of their actions. If there is a choice your teen must make, help them see the pros and cons of each choice. Because the prefrontal cortex is still developing, teens tend to be more impulsive. However, by helping them think through a situation, you help them make neural connections that build logical and rational thinking, which they will need as healthy and responsible adults.

Show interest in your teen. With all the growth teens go through, they may feel an inability to relate to their parents or other members of the family. You can support your teen by showing interest in what they like, such as their music, games, hobbies, and other interests. This also helps build neural connections in their brain that what they are interested in matters to you.

Talk to your teen about drug and alcohol use. Most teens respect the position their parents take on drug use, especially if parents remain consistent and are also modeling their message. Furthermore, most teens want the acceptance of their parents and will respect their direction they receive. And if parents discuss with their teen the health consequences that can result from drug use, teens are likely to have a better understanding of the risks when they are faced with peer pressure.

Encourage your teen to try new things. There is a lot of growth happening in the teen brain. The teen wants to try new things, explore the world, and role-play. A parent with a deeper understanding of a teen’s brain growth might encourage this for more neural connection and healthy growth.

Let your teen be social. Along with this growth in the brain, a teen wants to be surrounded by connection with others. Too much isolation could lead to risky behavior, poor decision-making, and perhaps even mental illness, such as depression. Strong friendships and relationships with family can support healthy adolescent growth.

Be patient with your teen’s emotional side. Teens can sometimes let out the Pandora’s Box of emotions. Although this can lead to moodiness, it points to the explosion of life that is happening within. When your teen is emotional or moody, be patient with them. Perhaps give them tools for coping with difficult emotions, such as breathing, journaling, exercising, and other tools. But give your teen the space they need to work through it.

Encourage your teen’s creativity. Adolescence is the stage in life when the brain is highly creative. You might support your teen’s curiosity, exploration, and interest in new things. Along with this, support your teen’s self-expression and creativity. All of this will not only facilitate healthy brain growth; it will also supports self-discovery, which is a necessary psychological task during adolescence.

These are suggestions for parents who want to facilitate a teen’s psychological development and healthy brain growth. If you have any concerns, however, about your teen’s emotional or psychological well being, contact a mental health professional today.

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