MAYBE TEENS ARE JUST WIRED THAT WAY

Changes In Brain Could Account For Erratic Behavior

Washington - Neuroscientist Jay Giedd was studying the brains of healthy
teen-agers when he noticed something odd: The brains appeared to change in
unexpected ways as the youths matured through adolescence.

When Giedd looked closer, the National Institute of Mental Health
researcher realized that the most dramatic shifts around puberty occurred
in the front of the brain, in an area believed crucial for advanced mental
functions such as reasoning, making judgments and self-control.

Could the alterations account for the impulsive, erratic and sometimes
irresponsible behavior often seen in teen-agers?

"Some kids are more likely to take risks than adults, and those are the
areas that are undergoing drastic changes," said Paul Thompson, a
mathematician and neurologist at the University of California at Los
Angeles who helped Giedd produce striking images of changes in healthy
teen-agers' brains. "It mirrors cognitive change."

Giedd and Thompson's work is part of a growing body of scientific evidence
suggesting that rebelliousness and other stereotypical teen-age behaviors
commonly blamed on raging hormones may be partly caused by a burst of rapid
change sculpting the developing teen-age brain.

The theory is speculative. But if it turns out to be true, it would
underscore the importance of guiding children carefully through
adolescence, because the right kinds of teen-age experiences might build
the structures and connections necessary for a healthy adulthood.

"If the teens are doing music and sports and academics, that's how their
brains will be hard-wired. If they are doing video games and MTV and lying
on the couch, that would be how they are hard-wired," Giedd said. "Teens
are most likely to experiment with drugs and alcohol. I often show teens my
data curve (and say), 'If you do this tonight, you may not be affecting
your brains just this weekend but for the next 80 years of your life.'"

The theory is controversial because the roots of behavior are complex and
cannot be easily explained by relatively superficial changes in the brain.
Critics say the theory reduces the range of teen-age behavior to stereotypes.

"The idea that because the frontal portions of the brain are immature and
therefore children undertake risky behavior is nonsense," said John Bruer,
president of the James S. McDonnell Foundation in St. Louis, which funds
research in cognitive neuroscience.

"What you have is folk theory about irresponsible, careless adolescents who
are annoying around the house, and people are making up these stories to
say behaviors can be rationalized by looking at fine brain structure,"
Bruer said. "The tendency here is to take our folk ideas and theories and
prejudices about what adolescent behavior should and shouldn't be and make
some biological explanation for that."

Giedd agreed that what scientists know for sure is limited, but he added
that the findings are intriguing. The solid data is the gray matter
thickens, peaks around puberty and thins. The rest is pretty much
speculation. There are very few things that we can say beyond that. I don't
mean to say that video games destroy the brain - the real answer is we
don't really know."

Scientists have struggled for hundreds of years to figure out how brain
changes affect behavior and which parts of the brain are responsible for
specific mental abilities.

Until recently, all scientists could do was study patients with brain
injury to see how the damaged areas affected behavior. They also examined
the brains of people who had died to look for unusual features that might
explain the person's behavior.

A confounding factor in such studies is that the brain often can compensate
for damage by rerouting wiring to healthy areas. In that sense, the image
of the brain as having interlocking Lego blocks that perform different
functions - the model of the pseudoscience phrenology - simply doesn't work.

But in recent years, advances in brain scan technology have allowed
researchers to evaluate which parts of the brain use energy while
performing certain tasks and which parts vary in their water content, which
distinguishes different types of tissue.

Researchers ask patients to perform mental tasks while being scanned to get
a snapshot of the brain in action. Such tests have suggested links between
behavior and performance and various brain structures.

"The more mature an individual's frontal lobe appeared, the better they
performed on the verbal test," said Elizabeth Sowell, an assistant
professor of neurology at the University of California at Los Angeles. "You
can take 10 8-year-olds, and there is a range of performance. We are
finding that the structure of the brain helps predict that variance."

[Accompanying diagram visually displays "Recent neurological studies
suggest that brain changes during adolescence may contribute to sudden
behavior shifts," showing areas of rapid brain tissue growth and areas of
brain tissue lost. The following are noted:
- - Age 3 to 6: Rapid growth in frontal lobe; possible effect, altertness,
attention span
- - Age 7 to 15: Rapid growth in temporal/parietal lobe; possible effect,
language mathematics
- - Age 16 to 20: Tissue loss in frontal lobe; possible effect, self-control,
planning
Source: Paul Thompson, UCLA neurology professor]