Myelination and Tween Impulses

Tween girls taking selfie

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. Here is what you need to know about the myelination process.


Myelination in the frontal cortex of the brain is an important part of the maturing process for adolescents. It also is vitally important to healthy central nervous system functioning and it occurs in the peripheral nervous system. 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.

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.

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.
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  3. Chevalier N, Kurth S, Doucette MR, et al. Myelination Is associated with processing speed in early childhood: Preliminary insightsPLoS One. 2015;10(10):e0139897. doi:10.1371/journal.pone.0139897

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  5. 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

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Additional Reading

By Rebecca Fraser-Thill
Rebecca Fraser-Thill holds a Master's Degree in developmental psychology and writes about child development and tween parenting.