Study: Pace of brain development still strong in late teens

May 10, 2011, Brown University

Boys and girls have put many of the trappings of teenagerhood behind them by the age of 18 or 19, but at least some of the brain resculpting that characterizes the decade of adolescence may still be going as strong as ever, according to findings in a new study that measured brainwaves of subjects in their midteens and again in their late teens.

One of the kinds of neurological changes underway in a teen brain is a pruning of unneeded connections forged earlier in life — the brain invests in developing some connections but sheds a higher volume of others. One way these changes can be measured, many researchers believe, is a drop in the power, or amplitude, of over time.

What researchers found in their study of sleeping teens, said Mary Carskadon, professor of psychiatry and human behavior at the Warren Alpert Medical School of Brown University and director of the Sleep Research Center at Emma Pendleton Bradley Hospital, is that this amplitude reduction continues at about the same pace in the late teen years as in earlier years.

"There was a sense that the bulk of the change is happening in the younger adolescents," said Carskadon, the paper's senior author. "To see a continuation of this rapid and large change in the older was a surprise."

Their results appear in advance online in the journal Sleep.

Numbers from slumber

To conduct the study, the researchers asked five boys and nine girls aged 15 and 16 to sleep to certain preparatory specifications for a week at home and then to spend two nights in the lab while the team took all-night measurements. Then they brought the teens back two or three years later, between the ages of 17 and 19, for another week of preparatory sleep and then two more nights of monitored sleep. Previously, researchers in Carskadon's lab had done a similar study with younger teens.

Over the course of the study, the researchers also noted some other changes in the children over time. For example, they found that late teens continue an earlier teen trend of spending less and less time in so-called "slow-wave" sleep in favor of "stage 2" sleep. Meanwhile, they found that the reduction in electroencephalography (EEG) power seems to shift from the left side early in the teen years to the right side later in adolescence. That shift means that by the end of the teen years, the developmental process has occurred equally on both sides.

Lead author Leila Tarokh, a researcher at the University of Zurich and adjunct assistant professor of psychiatry and human behavior at Brown, said that although many previous studies using EEG, magnetic resonance imaging, or postmortem examination have yielded similar measurements of adolescent brain changes, this study added insight because of how it was structured.

"The unique feature of this study is that it puts together these EEG measures of power and looks at these sleep stages longitudinally (in the same people over time) and across several regions around the brain," she said.

Carskadon said that sleep is a convenient time to take long-term, well controlled measurements of neural activity, but that the study does not show the role sleep may play in neural renovation among older teenagers.

"For us, is a window onto the ," Carskadon said.

Explore further: Teen sleep study adds to evidence of a 'neural fingerprint'

Related Stories

Teen sleep study adds to evidence of a 'neural fingerprint'

April 26, 2011
Teens are rarely described as stable, so when something about their rapidly changing brains remains placidly unaltered, neuroscientists take notice. Such is the case in a new study of electroencephalography (EEG) readings ...

Recommended for you

Finding unravels nature of cognitive inflexibility in fragile X syndrome

January 22, 2018
Mice with the genetic defect that causes fragile X syndrome (FXS) learn and remember normally, but show an inability to learn new information that contradicts what they initially learned, shows a new study by a team of neuroscientists. ...

Epilepsy linked to brain volume and thickness differences

January 22, 2018
Epilepsy is associated with thickness and volume differences in the grey matter of several brain regions, according to new research led by UCL and the Keck School of Medicine of USC.

Research reveals atomic-level changes in ALS-linked protein

January 18, 2018
For the first time, researchers have described atom-by-atom changes in a family of proteins linked to amyotrophic lateral sclerosis (ALS), a group of brain disorders known as frontotemporal dementia and degenerative diseases ...

Fragile X finding shows normal neurons that interact poorly

January 18, 2018
Neurons in mice afflicted with the genetic defect that causes Fragile X syndrome (FXS) appear similar to those in healthy mice, but these neurons fail to interact normally, resulting in the long-known cognitive impairments, ...

How your brain remembers what you had for dinner last night

January 17, 2018
Confirming earlier computational models, researchers at University of California San Diego and UC San Diego School of Medicine, with colleagues in Arizona and Louisiana, report that episodic memories are encoded in the hippocampus ...

Recording a thought's fleeting trip through the brain

January 17, 2018
University of California, Berkeley neuroscientists have tracked the progress of a thought through the brain, showing clearly how the prefrontal cortex at the front of the brain coordinates activity to help us act in response ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.