Module 4: "Teens and Decision Making" and "The Teen Brain"

This involves a relay system in which different structures—made up of specialized cells called neurons—talk with each other by way of electrochemical impulses and chemical messengers, called neurotransmitters.

This involves a relay system in which different structures—made up of specialized cells called neurons—talk with each other by way of electrochemical impulses and chemical messengers, called neurotransmitters.

A key brain region that matures late is the prefrontal cortex, located directly behind your forehead. The prefrontal cortex is very important as a control center for thinking ahead and sizing up risks and rewards.

Like the rest of the body, the brain needs to mature in order to reach peak performance. This process involves slow changes—strongly influenced by brain activity—that have evolved to fine tune (or optimize) how neural impulses flow throughout the brain, allowing it to process information faster and more reliably.

Inside the brain, information travels through a network of neurons, which have thread-like fibers called axons and branch-like structures called dendrites.

Dendrites bring information into the neurons, while axons take it away and pass it along to the next neuron.

Thus, neurons are assembled into circuits where the far end of an axon (its terminal) is positioned close to a dendrite. The small space between the two is called a synapse—where information is exchanged.

“It’s a resounding mantra of parents and teachers,” says Jensen, who’s a pediatric neurologist at Children’s Hospital in Boston.

Jensen is a Harvard expert on epilepsy, not adolescent brain development.

As she coped with her boys’ sour moods and their exasperating assumption that somebody else will pick up their dirty clothes, she decided to investigate what neuroscientists are discovering about teenagers’ brains that makes them behave that way.

Teenagers don’t have as much of the fatty coating called myelin, or “white matter,” that adults have in this area. Think of it as insulation on an electrical wire.

After all, if the brain is wired to form new connections in response to the environment, and potent psychoactive drugs suddenly enter that environment, those substances are “tapping into a much more robust habit-forming ability that adolescents have, compared to adults.”

So studies have shown that a teenager who smokes pot will still show cognitive deficits days later.

An adult who smokes the same dose will return to cognitive baseline much faster.

“And what she explained to me is that it will take [what you’ve been reading] from your short-term memory and while you sleep you will consolidate it. And actually you will know it better in the morning than right before you went to sleep.”