Tweens Growth & Development Myelination and Tween Impulses By Rebecca Fraser-Thill Rebecca Fraser-Thill LinkedIn Twitter Rebecca Fraser-Thill holds a Master's Degree in developmental psychology and writes about child development and tween parenting. Learn about our editorial process Updated on September 27, 2020 Fact checked Verywell Family content is rigorously reviewed by a team of qualified and experienced fact checkers. Fact checkers review articles for factual accuracy, relevance, and timeliness. We rely on the most current and reputable sources, which are cited in the text and listed at the bottom of each article. Content is fact checked after it has been edited and before publication. Learn more. by Cara Lustik Fact checked by Cara Lustik LinkedIn Cara Lustik is a fact-checker and copywriter. She has more than 15 years of experience crafting stories in the branding, licensing, and entertainment industries. Learn about our editorial process Print Ashley Corbin-Teich / Getty Images If you're noticing signs of maturity in your tween, like better reasoning skills, you can thank myelination. This process takes place when a substance called myelin, which is made up of fatty lipids and proteins, accumulates around nerve cells, or neurons, in the brain. Myelin plays an essential role in the health and function of nerve cells, the brain, and the nervous system. Myelination in the frontal cortex of the brain is an important part of the maturing process for adolescents. But it takes many years, so don't worry if your tween lacks impulse control, organization, and other signs of improved cognitive function. That's perfectly normal. Myelin's Function Nerve cells (neurons) have long shafts or elongated fibers known as axons. Myelin forms around the axons in what is often called the myelin sheath. Think of axons as wires of sorts that send electrical signals to the various parts of the body. Axons connect neurons to other cells, such as fellow neurons, muscle cells, and organs, at sites known as synapses. Myelin is comprised of glial support cells that protect axons, and so it has been likened to the insulation on electrical wires. (Although not all axons have a myelin coating.) Myelin enables nerve cells to transmit information faster and allows for more complex brain processes. The myelination process is vitally important to healthy central nervous system functioning. Myelination also occurs in the peripheral nervous system. How Myelination Affects Tweens Myelination begins in utero, when a fetus is about 16 weeks of age and continues into adulthood. During the tween years, myelination is particularly occurring in the frontal lobe of the brain. Myelination in this area is important for tweens' cognitive development. In particular, it helps them build better executive functioning skills, which include planning, reasoning, and decision-making. Myelination of the frontal lobe also helps tweens inhibit their impulses more efficiently and demonstrate greater self-discipline. Still, many tweens and teens continue to have impulse control problems, because the frontal lobe doesn't reach maturity until about the age of 25. When Myelin Suffers Damage When this fatty substance is damaged it can lead to potentially devastating disorders such as multiple sclerosis (MS). When MS occurs, it's believed that the immune system malfunctions and launches an attack on the myelin sheath, resulting in lesions. Problems with myelin have also been linked to fibromyalgia, adrenoleukodystrophy (ALD), Krabbe disease, Charcot-Marie-Tooth disease (CMT), Guillain-Barré Syndrome, small fiber neuropathy and chronic inflammatory demyelinating polyneuropathy. All of these medical conditions involve the nerves, and the people who have them typically suffer pain, muscle weakness, numbness, and sensory changes as a result. If you or a loved one, including your tween, is displaying signs like these, don't delay getting medical help. While sometimes nerve damage occurs gradually over a long period of time, other times its effects can be felt quickly. In either case, it's important to seek health care as soon as possible before the disease progresses. Was this page helpful? Thanks for your feedback! Get diet and wellness tips to help your kids stay healthy and happy. Sign Up You're in! Thank you, {{form.email}}, for signing up. There was an error. Please try again. What are your concerns? Other Inaccurate Hard to Understand Submit 6 Sources Verywell Family uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. Williamson JM, Lyons DA. Myelin dynamics throughout life: An ever-changing landscape?. Front Cell Neurosci. 2018;12:424. doi:10.3389/fncel.2018.00424 Arain M, Haque M, Johal L, et al. Maturation of the adolescent brain. Neuropsychiatr Dis Treat. 2013;9:449–461. doi:10.2147/NDT.S39776 Chevalier N, Kurth S, Doucette MR, et al. Myelination Is associated with processing speed in early childhood: Preliminary insights. PLoS One. 2015;10(10):e0139897. doi:10.1371/journal.pone.0139897 Bercury KK, Macklin WB. Dynamics and mechanisms of CNS myelination. Dev Cell. 2015;32(4):447–458. doi:10.1016/j.devcel.2015.01.016 Hu B, Mccollum M, Ravi V, et al. Myelin Abnormality in CMT4J Recapitulates Features of Acquired Demyelination. Ann Neurol. 2018;83(4):756-770. doi:10.1002/ana.25198 Duncan ID, Radcliff AB. Inherited and acquired disorders of myelin: The underlying myelin pathology. Exp Neurol. 2016;283(Pt B):452–475. doi:10.1016/j.expneurol.2016.04.002 Additional Reading Berger, K. (2020). The Developing Person Through the Life Span. United States: Macmillan Learning.