Researchers thought that the brain's key development
finished within the first few years of life. Then recently
they discovered that important brain regions continue to
undergo refinement at least into a person's early twenties.
For example, one study compared the brain structure of kids
aged 12 to 16 with young adults aged 23 to 30. Several brain
areas showed signs that their circuits pare down and fine
tune between adolescence and young adulthood. Included is
the frontal cortex, which helps process highly complex
information. Another study examined molecular changes in the
memory brain area, known as the hippocampus, and found that
it is still maturing in rats equivalent in age to human
teenagers.
The
findings imply that introducing alcohol during this
developmental stage can potentially harm the growing system
and associated brain functions, such as learning and memory.
Several, more specific studies, back this idea.
In one
report, the equivalent of about five drinks in people
impairs the ability of adolescent rats, but not adults, to
learn a memory task. Other research examined two molecular
processes tied to memory, termed long-term protestation and
N-methyl-D-aspirate receptor activity. Adolescent rats that
received the equivalent of about one to two drinks
experience more interference with these processes than do
adults.
Perhaps
most troublesome is work suggesting long-lasting
alterations. One study found that the equivalent of about 10
drinks produces more extensive brain damage in adolescent
rats than in adults.
Findings
are hard to confirm in humans because scientists can't
provide underage children with alcohol and then dissect
their brains. Some evidence, however, is in line with the
animal work.
For
example, a study of young people indicates that those who
start drinking during adolescence have smaller hippocampus
memory areas than non-drinkers. Another study finds that
following the consumption of about two to three drinks,
people in their early twenties perform worse on memory tests
than people in their late twenties. More recently
researchers examined subjects aged 18 to 25 who reported a
history of drinking about a six-pack on weekend nights.
Compared with non-drinkers, they perform somewhat worse on
memory tasks. Furthermore, their performance correlates with
poor brain activity. Preliminary findings show similar
results with younger teens who drink heavily (see images).
Their brain response is also diminished, although they
manage to perform okay on the tasks. The researchers plan to
investigate further how various drinking histories affect
different age groups.
Some
scientists also believe that the immature young brain may
put kids at a disadvantage when they encounter situations
involving alcohol. Possibly, their brains can't provide the
foresight that they should avoid drinking because it's
dangerous. Also, once experimentation begins, brain areas
that make a person feel good and want to drink again may be
in an underdeveloped state and more easily influenced.
Overall,
the research adds fire to an often-repeated message: Just
say no.
