The vast majority of brain development occurs in two basic stages: growth spurts and pruning (Inside the Teenage Brain, Frontline, PBS).

We’ve known that “in utero and throughout the first several months of life, the human brain grows at a rapid and dramatic pace, producing millions of brain cells.” However, between ages 10 and 13, there is a second wave of rapid development that is quickly followed by a process in which the brain prunes and organizes its neural pathways(Inside the Teenage Brain, Frontline, PBS).

According to Giedd, “our leading hypothesis … is the ‘use it or lose it’ principle,..if a teen is doing music or sports or academics, those are the cells and connections that will be hardwired. If they’re lying on the couch or playing video games or [watching] MTV, those are the cells and connections that are going to survive” (Inside the Teenage Brain, Frontline, PBS).

Mary Carskadon, director of the E.P. Bradley Hospital Sleep Research Laboratory at Brown University, says that on average, teens require more than 9 hours of sleep per night. However, most teens get about seven and a half hours of sleep, creating a sleep debt (Inside the Teenage Brain, Frontline, PBS). 

 Sleep debts affect a teen’s ability to learn and retain information, particularly, abstract concepts (Inside the Teenage Brain, Frontline, PBS).

The brain consolidates and practices what is learned during the day after we go to sleep. Learning actually continues to take place while a person is asleep.

The brain consolidates learning during two particular phases of sleep. According to Dr. Robert Stickgold of Harvard University Medical School, “the brain seems to need lots of slow-wave sleep and a good chunk of another kind of sleep, Rapid Eye Movement, or REM. Dr. Stickgold hypothesizes that the reason the brain needs these particular kinds of sleep is that certain brain chemicals plummet during the first part of the night, and information flows out of the hippocampus (the memory region) and into the cortex. He thinks the brain then distributes the new information into appropriate networks and categories. Inside the brain, proteins strengthen the connections between nerve cells consolidating the new skills learned the day before. Then later, during REM, the brain re-enacts the lessons from the previous day and solidifies the newly-made connections through the memory banks” (Inside the Teenage Brain, Frontline, PBS).

“Sleep experts say dimming the lights at night and getting lots of daylight in the morning can help. Having a routine bedtime of 10 p.m., sleeping in a cool environment and turning off music, the Internet, and televisions would help to reset the body clock. And though sleeping in is a good thing, trying to get up after only an extra hour or two is a lot better than “binge-sleeping” on the weekends. If a student is used to getting up at 6:30 a.m., they shouldn’t sleep until noon on the weekend. That simply confuses their bodies. And lots of sports helps, too — better earlier in the day than late” (Inside the Teenage Brain, Frontline, PBS).

Deborah Yurgelun-Todd and a group of researchers have studied how adolescents perceive emotion as compared to adults. Adults and teens were shown pictures of adult faces and asked to identify the emotion expressed. Using fMRI, the researchers traced the part of the brain responded as subjects were asked to identify the expression depicted in the picture.

The adults correctly identified the emotions expressed in the pictures, but the teens misinterpreted the expressions. The teens and adults also used different parts of their brains to process the information. The fMRI showed the amygdala most active in teens. This mid-brain structure guides instinctual or “gut” reactions. In adults, the frontal cortex, which governs reason and planning, was active during this exercise.

As the teens got older, the center of activity shifted more toward the frontal cortex and away from the amygdala (Inside the Teenage Brain, Frontline, PBS).

 Ellen Galinsky, a social scientist and the president of the Families and Work Institute, found that in her interviews with more than a thousand children, teens desire more time and more communication with their parents, even when they seemed to be pushing parents away. “Even though the public perception is about building bigger and better brains, what the research shows is that it’s the relationships, it’s the connections, it’s the people in children’s lives who make the biggest difference” (Inside the Teenage Brain, Frontline, PBS).