What parts of the brain have an effect on adolescence and how they develop?
It doesn’t matter how smart teens are or how well they scored on the SAT or ACT. Good judgment isn’t something they can excel in, at least not yet. Show The rational part of a teen’s brain isn’t fully developed and won’t be until age 25 or so. In fact, recent research has found that adult and teen brains work differently. Adults think with the prefrontal cortex, the brain’s rational part. This is the part of the brain that responds to situations with good judgment and an awareness of long-term consequences. Teens process information with the amygdala. This is the emotional part. In teens' brains, the connections between the emotional part of the brain and the decision-making center are still developing—and not always at the same rate. That’s why when teens have overwhelming emotional input, they can’t explain later what they were thinking. They weren’t thinking as much as they were feeling. What's a parent to do?You’re the most important role model your kids have. Sure, their friends are important to them, but the way you behave and fulfill your responsibilities will have a profound and long-lasting effect on your children.
Parents tend to jump in with advice to try to fix their children’s problems or place blame. But this can make teens less likely to be open with their parents in the future. You want to make it emotionally safe and easy for them to come to you so you can be part of their lives. Signs of troubleIt’s normal for teens to be down or out of sorts for a couple of days. But if you see a significant mood or behavioral change that lasts more than 2 weeks, it could mean something else is going on, such as depression. If you think your teen could be depressed, promptly seek professional treatment for your child. Depression is serious and, if left untreated, can be life-threatening. Your teen needs your guidance, even though they may think they don’t. Understanding their development can help you support them in becoming independent, responsible adults. \( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \) \( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}} \)\(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\) \(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\)\(\newcommand{\AA}{\unicode[.8,0]{x212B}}\)
Learning Outcomes
The human brain is not fully developed by the time a person reaches puberty. Between the ages of 10 and 25, the brain undergoes changes that have important implications for behavior. The brain reaches 90% of its adult size by the time a person is six or seven years of age. Thus, the brain does not grow in size much during adolescence. However, the creases in the brain continue to become more complex until the late teens. The biggest changes in the folds of the brain during this time occur in the parts of the cortex that process cognitive and emotional information. Up until puberty, brain cells continue to bloom in the frontal region. Some of the most developmentally significant changes in the brain occur in the prefrontal cortex, which is involved in decision making and cognitive control, as well as other higher cognitive functions. During adolescence, myelination and synaptic pruning in the prefrontal cortex increases, improving the efficiency of information processing, and neural connections between the prefrontal cortex and other regions of the brain are strengthened. However, this growth takes time and the growth is uneven. The Teen Brain: 6 Things to KnowFigure 1. The brain reaches its largest size in the early teen years, but continues to mature well into the 20s. As you learn about brain development during adolescence, consider these six facts from the The National Institute of Mental Health: Your brain does not keep getting bigger as you get olderFor girls, the brain reaches its largest physical size around 11 years old and for boys, the brain reaches its largest physical size around age 14. Of course, this difference in age does not mean either boys or girls are smarter than one another! But that doesn’t mean your brain is done maturingFor both boys and girls, although your brain may be as large as it will ever be, your brain doesn’t finish developing and maturing until your mid- to late-20s. The front part of the brain, called the prefrontal cortex, is one of the last brain regions to mature. It is the area responsible for planning, prioritizing and controlling impulses. The teen brain is ready to learn and adaptIn a digital world that is constantly changing, the adolescent brain is well prepared to adapt to new technology—and is shaped in return by experience. Many mental disorders appear during adolescenceAll the big changes the brain is experiencing may explain why adolescence is the time when many mental disorders—such as schizophrenia, anxiety, depression, bipolar disorder, and eating disorders—emerge. The teen brain is resilientAlthough adolescence is a vulnerable time for the brain and for teenagers in general, most teens go on to become healthy adults. Some changes in the brain during this important phase of development actually may help protect against long-term mental disorders. Teens need more sleep than children and adultsAlthough it may seem like teens are lazy, science shows that melatonin levels (or the “sleep hormone” levels) in the blood naturally rise later at night and fall later in the morning than in most children and adults. This may explain why many teens stay up late and struggle with getting up in the morning. Teens should get about 9-10 hours of sleep a night, but most teens don’t get enough sleep. A lack of sleep makes paying attention hard, increases impulsivity and may also increase irritability and depression. The limbic system develops years ahead of the prefrontal cortex. Development in the limbic system plays an important role in determining rewards and punishments and processing emotional experience and social information. Pubertal hormones target the amygdala directly and powerful sensations become compelling (Romeo, 2013). [1] Brain scans confirm that cognitive control, revealed by fMRI studies, is not fully developed until adulthood because the prefrontal cortex is limited in connections and engagement (Hartley & Somerville, 2015). [2] Recall that this area is responsible for judgment, impulse control, and planning, and it is still maturing into early adulthood (Casey, Tottenham, Liston, & Durston, 2005). Figure 2. Brain development continues into the early 20s. The development of the frontal lobe, in particular, is important during this stage. Additionally, changes in both the levels of the neurotransmitters dopamine and serotonin in the limbic system make adolescents more emotional and more responsive to rewards and stress. Dopamine is a neurotransmitter in the brain associated with pleasure and attuning to the environment during decision-making. During adolescence, dopamine levels in the limbic system increase and input of dopamine to the prefrontal cortex increases. The increased dopamine activity in adolescence may have implications for adolescent risk-taking and vulnerability to boredom. Serotonin is involved in the regulation of mood and behavior. It affects the brain in a different way. Known as the “calming chemical,” serotonin eases tension and stress. Serotonin also puts a brake on the excitement and sometimes recklessness that dopamine can produce. If there is a defect in the serotonin processing in the brain, impulsive or violent behavior can result. When the overall brain chemical system is working well, it seems that these chemicals interact to balance out extreme behaviors. But when stress, arousal or sensations become extreme, the adolescent brain is flooded with impulses that overwhelm the prefrontal cortex, and as a result, adolescents engage in increased risk-taking behaviors and emotional outbursts possibly because the frontal lobes of their brains are still developing. Later in adolescence, the brain’s cognitive control centers in the prefrontal cortex develop, increasing adolescents’ self-regulation and future orientation. The difference in timing of the development of these different regions of the brain contributes to more risk taking during middle adolescence because adolescents are motivated to seek thrills that sometimes come from risky behavior, such as reckless driving, smoking, or drinking, and have not yet developed the cognitive control to resist impulses or focus equally on the potential risks (Steinberg, 2008). [3] One of the world’s leading experts on adolescent development, Laurence Steinberg, likens this to engaging a powerful engine before the braking system is in place. The result is that adolescents are more prone to risky behaviors than are children or adults. Watch ITThis video further explains and highlights some of the key developments in the brain during adolescence. An interactive or media element has been excluded from this version of the text. You can view it online here: http://pb.libretexts.org/lsdm/?p=270 You can view the transcript for “Brain changes during adolescence | Behavior | MCAT | Khan Academy” here (opens in new window). As mentioned in the introduction to adolescence, too many who have read the research on the teenage brain come to quick conclusions about adolescents as irrational loose cannons. However, adolescents are actually making choices influenced by a very different set of chemical influences than their adult counterparts—a hopped up reward system that can drown out warning signals about risk. Adolescent decisions are not always defined by impulsivity because of lack of brakes, but because of planned and enjoyable pressure to the accelerator. It is helpful to put all of these brain processes in developmental context. Young people need to somewhat enjoy the thrill of risk taking in order to complete the incredibly overwhelming task of growing up. Watch ItWatch the selected portion of this video to learn more about research related to brain changes and behavior during adolescence. A YouTube element has been excluded from this version of the text. You can view it online here: http://pb.libretexts.org/lsdm/?p=270 You can view the transcript for “The Teenage Brain Explained” here (opens in new window). To learn more, watch this TED talk by Sarah-Jayne Blakemore: The mysterious workings of the adolescent brain about the latest adolescent brain research and more about how these changes in brain development also result in behavioral changes. Key TakeawaysIn sum, the adolescent years are a time of intense brain changes. Interestingly, two of the primary brain functions develop at different rates. Brain research indicates that the part of the brain that perceives rewards from risk, the limbic system, kicks into high gear in early adolescence. The part of the brain that controls impulses and engages in longer-term perspective, the frontal lobes, matures later. This may explain why teens in mid-adolescence take more risks than older teens. As the frontal lobes become more developed, two things happen. First, self-control develops as teens are better able to assess cause and effect. Second, more areas of the brain become involved in processing emotions, and teens become better at accurately interpreting others’ emotions.[4] Try Ithttps://assessments.lumenlearning.co...essments/16610 SleepBrain development even affects the way teens sleep. Adolescents’ normal sleep patterns are different from those of children and adults. Teens are often drowsy upon waking, tired during the day, and wakeful at night. Although it may seem like teens are lazy, science shows that melatonin levels (or the “sleep hormone” levels) in the blood naturally rise later at night and fall later in the morning in teens than in most children and adults. This may explain why many teens stay up late and struggle with getting up in the morning. Teens should get about 9-10 hours of sleep a night, but most teens don’t get enough sleep. A lack of sleep makes paying attention hard, increases impulsivity, and may also increase irritability and depression.[5] Link to Learning: School Start TimesAs research reveals the importance of sleep for teenagers, many people advocate for later high school start times. Read about some of the research at the National Sleep Foundation on school start times or watch this TED talk by Wendy Troxel: “Why Schools Should Start Later for Teens”. glossary[glossary-page] [glossary-term]dopamine:[/glossary-term] [glossary-term]frontal lobes:[/glossary-term] [glossary-term]limbic system:[/glossary-term] [glossary-term]melatonin:[/glossary-term] [glossary-term]myelination:[/glossary-term] [glossary-term]prefrontal cortex:[/glossary-term] [glossary-term]serotonin:[/glossary-term] [glossary-term]synaptic pruning:[/glossary-term]
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