Giedd is a neuroscientist at the National Institute of Mental Health. Recently, he spearheaded research showing for the first time that there is a wave of growth and change in the adolescent brain. He believes that what teens do during their adolescent years -- whether it's playing sports or playing video games -- can affect how their brains develop.

Yurgelun-Todd is the director of neuropsychology and cognitive neuroimaging at McLean Hospital in Belmont, Mass. Her recent work suggests that teens' brains actually work differently than adults' when processing emotional information from external stimuli.

New imaging technology has offered neuroscientists an unprecedented glimpse into the structures and processes of the human brain. Recent studies by Dr. Jay Geidd of the National Institutes of Health reveal a surprising growth spurt in the brains of teenagers just before puberty. Here's an overview of the emerging research on the growth of adolescents' brains, by FRONTLINE producer Sarah Spinks.

An interactive illustration showing the parts of the brain that change the most during the teen years.

FRONTLINE asked four prominent psychologists and neuroscientists to answer via email some questions about the extent of our knowledge of the brain and its development -- connections between the anatomy of the brain and behavior, new directions for research, and how close we are to translating new findings into advice for parents or educators.

A report from FRONTLINE producer Sarah Spinks on new research that suggests teens process emotional information differently than adults, and even use different parts of their brains to do so.

In the popular press, much has been made of research indicating that there are certain crucial periods during which children must be exposed to specific stimuli or risk missing important developmental steps. FRONTLINE producer Sarah Spinks examines the science behind these claims and finds that, for the most part, human learning and development is not limited to certain critical periods, but takes place throughout a person's lifespan.