[blparent] The brain of your child

[Veronica Smith]

going mental. For the first two months in the womb, you weren't a girl or a
boy-as far as your brain was concerned, anyway. Then it began the lifelong
journey of making you the smart, unique woman you are today. in UTERO. The
brain begins developing three weeks into pregnancy, forming 100 billion
neurons or nerve cells-a lifetime peak-by the time a fetus is five months
old. During those first eight weeks, all brains follow the same
developmental path. Then testosterone starts to marinate boys' brains," says
Louann Brizendine, M.D., a neuropsychiatrist and author of The Female Brain.
This hormone bath kills some cells in brain regions that promote
communication and emotion, while spurring cell growth in the sex and
aggression centers. By the time we're born, we have female- or male-type
brain circuits, Dr. Brizendine says.

birth to age 5. Our brain is more "plastic," or impressionable, now than at
any other time in life, Dr. Brizendine says. It's also growing fast: By your
fifth birthday, your brain is 90 percent of its adult size! This is a great
time to learn a second language; it builds an enhanced ability to
concentrate that can last into adulthood and may even delay age-related
dementia. Experts aren't yet sure why, but bilingual adults have denser gray
matter in areas that help control language and communication, suggesting
that learning multiple languages as a kid increases blood and oxygen flow to
the brain and keeps nerve connections healthy.

Ages 5 to 20. By now our brain has begun to select the neural connections we
use regularly and get rid of the rest. This process fosters a healthy brain
in the same way pruning promotes a healthy tree-by nixing unnecessary
branches that compete for nutrients. Meanwhile, a fatty substance called
myelin coats your axons, long fibers that connect nerve cells, to speed
processing. Before puberty, there's a second growth spurt in the frontal
lobe, which controls impulse control and reasoning, although some research
indicates our reasoning centers aren't fully developed until young adulthood
(which goes a long way toward explaining prom night).

ADULT hood. At age 20, our brain cells begin to die, and we lose 10 percent
over a lifetime. But we continue to generate neurons, albeit at a slower
pace, Dr. Brizendine says. Women's brains are on average 9 percent smaller
than men's, but they're more dense with cells-and equally capable of making
brilliant discoveries and decisions. Young men's brains devote more area to
centers for fear, aggression and sex, which may explain why they think about
sex three times more than we do, Dr. Brizendine says. (It crosses a young
woman's mind one to four times a day.) So there you have it: the real answer
to "What are you thinking about?

motherhood. Feel like an alien stole your brain? A woman's brain shrinks 8
percent during pregnancy. The whys aren't fully understood (perhaps nature
is prepping you for Bob the Builder), but the theory is that surges of the
bonding hormone oxytocin may be restructuring brain circuits, rerouting
energy and nutrients to the regions dedicated to attachment and baby
tracking. And never fear: Brain size returns to normal six months post-baby,
so if you're still feeling spacey, chalk it up to sleep deprivation and
stress. Both have been shown to decrease brain function temporarily in
numerous studies.

PERIMENOPAUSE. As women begin to transition into menopause, natural
fluctuations in levels of the sex hormones estrogen and testosterone affect
the neurotransmitters that control mood and memory. As a result, some
(lucky) women experience zestful surges of libido and energy, others feel
depressed, and many women alternate back and forth between the states,
sometimes seemingly from minute to minute. Women and men experience normal
memory declines in middle age: At 45, you'll probably have a 35 percent loss
of memory for names compared with your recall prowess at age 25.

age 50 and up. Age-related memory loss is totally normal in everyone older
than 50-not to be confused with Alzheimer's and other forms of dementia,
which affect about 4.5 million mostly elderly Americans. A number of
studies, however, show that simple lifestyle improvements such as adding a
vigorous walk to your daily routine can actually slow decline, create brain
cells and improve memory. So if you're dreading menopause or an empty nest,
consider this: Freedom from raging hormones and child rearing can give you
the time and energy to learn and achieve, engaging in activities that
recharge your brain.