Startling evidence has changed the way we think about adolescence. We previously thought that the most significant brain growth happens before age 3. Now we know that there is a “brain spurt” just before puberty, with lots of new gray matter — the part of the brain responsible for thinking.
During the rest of adolescence, much of the new gray matter goes away. Which parts remain depend on the nature of a teen’s activities.
Adolescence is in many ways a fresh start for the brain, a chance to hardwire the brain for the rest of life. “Use it or lose it,” is the simplified principle, as teens design their brains for the future with the choices they make now!
Nature Neuroscience 1999;2:859-861, 861-863.