BLAME IT ON THE AMYGDALA
Getting insight
into teenagers’
erratic behavior
By DAN DeLEO
The Patriot Ledger
HINGHAM – Parents, you were right all along:
Your teenagers are out of their minds.
Or, put more accurately, they just haven’t grown in-
to them yet.
At least that’s what Dr. Marisa M. Silveri told about
150 parents and educators during a lecture last night
on the development of the adolescent brain, an organ
that has perplexed and vexed mothers and fathers for
time immemorial.
Silveri believes a child’s brain may reach its maxi-
mum size by age 5, but the human being it controls
doesn’t begin behaving in a rational way for at least
another 15 years.
Impulsive behavior, poor judgment, even messy
bedrooms can all be blamed on the changes going on
inside a teen’s head. In scientific terms, the frontal lobe
– the executive branch of the brain – is slowly gaining
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Insight
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erratic
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control over other parts of the brain
that act as conduits of stimuli.
That rewiring is the reason teens
are, well, the way they are, Silveri
said. “The frontal lobe is all revved
up,” she said. “There’s substantial
remodeling happening.” Teens
may look like adults, she said, but
their brains function differently.
Silveri, a neuroscientist at
McLean Hospital in Belmont,
peered inside teenage brains using
MRI technology. She measured
the amount of tissue in the adoles-
cent brain and how the brain reacts
to different stimuli, everything
from pictures of greasy cheese-
burgers to photos of faces locked
in frightful stares.
She spoke at Hingham High
School at an event sponsored by
the South Shore School Partner-
ship for Health and The Adoles-
cent Suicide Prevention Project.
Silveri reported results of sever-
al studies under way at the Cogni-
tive Neuroimaging Laboratory at
McLean, which is run by Harvard
University’s Department of Psy-
chiatry.
Teen brains are less adept at ex-
ecuting “inhibitory control,” which
is why they wind up at the mall
when they should be studying for a
final exam, she said.
She blames that on the amygdala
(pronounced a-Mig-duh-luh) path-
way, the sort of gatekeeper of stim-
uli. In teenagers, the frontal lobe al-
lows information to flow through
this pathway at a much faster clip
than in adults. “But as the frontal
lobe matures, it begins to take con-
trol over the amygdala,” she said.
Just as the teen brain is rapidly
changing through adolescence, it
is also in a vulnerable state, Silveri
said. Lack of sleep, poor eating
habits, and the use of drugs and/or
alcohol can all alter the healthy de-
velopment of the adolescent brain,
she said.
Also, she added, younger people
tend to become more easily addicted
to drugs or alcohol when compared
to those who begin using as adults.
Alcohol is especially destructive,
she said, hindering the teen brain’s
ability to learn and remember, skills
needed for academic success.
Luckily, the teen brain is also a
resilient organ. Although some
chronic drug or alcohol use can
cause permanent damage, some
effects are reversible, she added.
Kathie Olsson, who teaches
health in Weymouth, said she
plans to present what she learned
from Silveri to her students.
“It’s so easy for them to make
mistakes,” said Olsson, a Hingham
resident who teaches at Abigail
Adams Middle School. “All you
can do is give them the knowledge
and hope they use it.”
Carole Ribaudo, a Scituate
mom, walked away from Silveri’s
presentation saying she understood
her 11-year-old son a little better.
“As a parent, you need to be
armed as best you can,” she said.
“Now I know I need to be his
frontal lobe.”
Dan DeLeo may be reached at
ddeleo@ledger.com.