[language] [Fwd: Baby's dancing brain craves words, touch]

[H.M. Hubey]

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Baby's dancing brain craves words, touch

By Tamara Koehler
Scripps Howard News Service

An infant stares at mom's face, not a trace of understanding in the
still-focusing eyes.

And yet behind that wide-eyed gaze and soft cap of bone, an electrical
storm is taking place.

BUILDING A BRAIN

New brain-imaging technologies in the past decade have shown:

It's nature, then nurture. Genes provide each brain's basic building
materials. The environment builds it through trillions of brain-cell
connections made by sight, sound, smell, touch and movement. Positive
experiences enhance brain connections, and negative experiences damage
them.

Words work wonders. Babies whose mothers and fathers talk to them
routinely more often have larger vocabularies and tend to learn to read
sooner and better.

Movement matters. Children who spend too much time in playpens and not
enough on jungle gyms don't develop the motor cortex area of the brain
and, as a result, show poor school readiness.

Music matters. Piano instruction in particular can enhance the brain's
ability to visualize ratios, fractions and proportions, and thus to
learn math and logic.

Neglect hurts. Depriving an infant of loving talk and touch releases
steroids that damage the brain's hippocampus, which controls its
stress-response systems, and can lead to serious cognitive, emotional
and social problems.

Stress hurts. Chronic stress such as poverty, abuse or violence can
impair the development of the amygdala, an almond-shaped area deep in
the brain that houses emotion and memory. It also can confuse chemicals
that moderate impulsive behavior, fear and aggression.

------------------------------------------------------------------------

Deep inside the 1-pound infant brain, millions of wispy circuits are
zapping and firing, paving electrical roads and bridges that will carry
the heavy traffic of learning, questioning and creating throughout life.

The first five years of life are a crucial period for learning - a short
but spectacular window of time when experiences such as a whisper, a hug
and a bedtime lullaby can change the architecture of the developing brain.

"We now have concrete images of the way the brain is hooked up early in
life, and it is truly a remarkable period like no other in life," said
Dr. Harry Chugani, a neuroscientist at the Children's Hospital of
Michigan in Detroit.

But interacting in these key years is far more than child's play, and
the deprivation of talking, responding, smiling and playing in a child's
life can forever change the course of that life cognitively,
educationally and emotionally, scientists say.

Long before the school years, the groundwork for how well a child will
succeed and thrive is already being laid.

"There is so much at play - genetics, nutrition, peers - nothing is set
in stone," said Dr. Pat Kuhl, co-director of the University of
Washington's Center for Mind, Brain & Learning.

"But what we do know is this is a critical time when you can help a
child be ready for school, be at the highest level of development he or
she can be."

The extraordinary development of the human brain begins a few weeks
after conception. Neurons - the brain cells that store and send
information - begin multiplying at 50,000 per second, a frenzy that
continues throughout gestation.

 From that point on, environment begins to play its starring role in the
way the brain is wired for emotion, behavior and learning.

Neurons send signals to other neurons through axons, a thin fiber that
relays electrical messages. Once an axon finds its target cell, it
develops dendrites, or branches, which receive a wide variety of
information from other brain cells. The more dendrites a nerve cell has,
the better and quicker it is at learning.

At birth, the infant brain has few of these branches. Its neurons look
like saplings. Adult neurons resemble trees with hundreds of branches
formed through experience and learning.

"A well-stimulated child's brain - and an adult's, for that matter - is
visibly different under the microscope," said Dr. Lise Eliot, a
neuroscientist with the Chicago Medical School.

"A well-connected brain is a forest of dendrites," Eliot said. "In
severely neglected children, those dendrite branches are not as dense,
which means the quality of connections and the ability to learn is
affected."

Young brains work at warp speed. An infant's brain can form new learning
connections at a rate of 3 billion per second. A child's brain uses
twice as much glucose, the brain's fuel, as that of a chess master
plotting three moves in advance.

How fast brain signals travel along these dendrites depends on how well
their axons are coated with myelin, a fatty coating similar to plastic
insulation around an electrical wire.

Myelin sheaths enable brain signals to travel 100 times faster.

Babies are born with few myelinated axons. That's one reason infants
can't see well and can't do much with their hands other than grasping
and batting at objects.

As children get older, different areas of the brain become myelinated on
a genetically determined timetable. These periods of mylenization are
critical periods for learning. For instance, the first axons to be
myelinated in the language area of the brain are those that enable
language comprehension. Six months later, myelination extends to the
language-production area.

Children who are malnourished, especially during these critical periods,
have less myelination. This can explain learning problems like being a
slow reader, Eliot said.

Myelination continues well into the teenage years, primarily in the
frontal lobe where decision making and rational capacity develop.

The wonders of a child's brain are not without limits.

Brief and early phases during development open parts of the brain that
control vision and language to stimulation, then close forever.

Experiments performed on kittens in which one eye is sewn shut reveal
that the closed eye remains nonfunctional even after the stitches are
removed, for example.

Another stark example of this use it or lose it phenomenon is language
learning.

By 6 months of age, infants develop a map in the auditory cortex of the
phonetic sounds in the native language their mother or caretaker speaks.

By 12 months, infants lose the ability to discriminate between sounds
that are not made in their native language.

While subtle phonetic distinctions might be lost in the first year,
children have the ability to learn a second, third and fourth language
quickly until about age 10.

After that, the brain starts discarding the excess language learning
connections. After 10, learning a foreign language is still possible but
more difficult.

This pruning of unused or unneeded neuron connections is necessary for
thinking clearly, making fast associations, reacting to threats and
solving problems.

But the pruning process also can work against the growing child,
especially if connections that could have proved useful later in life
are killed because of lack of use.

Only those connections that are reinforced over and over again will remain.

http://www.abqtrib.com/archives/news03/081903_news_science.shtml


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--
Mark Hubey
hubeyh at mail.montclair.edu
http://www.csam.montclair.edu/~hubey



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