When it comes to the brain, the old saw, "use it or lose it" appears to be true.

Researchers no longer believe that brain cells that die can never be replaced. Like any muscle in the body, if the brain is exercised, it becomes stronger and more efficient.

Good evidence suggests that the brain can reroute pathways following injury or stroke.

Brain research is a growing field. The fact is, most people will either experience some kind of brain-related illness or have to help a loved one cope. And disorders of the brain and central nervous system are among the leading causes of death or disability in the United States, with one of five Americans facing a neurological or psychiatric illness.

It's particularly important because in the past century life expectancy has risen from the mid-40s to 75. And many of the diseases that affect the brain seem to occur at least in tandem with the aging process, if they're not directly related to it.

Researchers know that to find solutions to the disabilities and diseases, they will have to learn more about how the brain works.

A child's brain

The brain's development is never more dramatic and fast-paced than between birth and age 3. And horrible things can happen when a baby's brain development goes wrong. That's why health-care professionals a few years ago launched a campaign to get women to take folic acid (vitamin B), which is crucial to prevent spina bifida. They emphasize nutrition, abstinence and exercise to assure that tiny brain's best chance to thrive.

It is in the first 10 years of life that cell pathways form, making that period ideal for learning language and grasping the basics of such things as math. The pathways become "hard, permanent wiring" for the parts of the brain that will be the centers for planning, language expression, speech, movement, touch, taste, vision and more.

Sensory stimulation plays a huge role in that. Researchers have found that babies with chatty mothers are more likely to develop good language and thinking skills than babies who don't get talked to a lot. They say to read to your baby, talk to her, play with her and let her see the world. Science also indicates that music — especially classical music — helps the brain's paths develop.

It's important to remember that children are not small adults, according to pediatric neurosurgeons at Primary Children's Medical Center. Just as there are structural differences in the child and adult brains, there are also differences in how the injuries and illnesses that affect them should be treated.

The terrible teens

The Charles A. Dana Foundation, which promotes brain study and education and publishes regular reports and updates, says the teenage years provide the biggest mystery when it comes to brain development. But scientists suspect that what happens in these years is just as important in many ways as the changes that take place in an infant and young child's brain.

It's a fact that there's a large increase in the sprouting of synapses just before puberty, immediately followed by what the foundation calls an "aggressive pruning of connections that are not sufficiently activated." That may contradict the hard-wiring theory of a child's brain path being set by about age 3.

The foundation reports that the pruning period "may be a time of exquisite sensitivity to experiential influneces." So studying the violin for an hour as a teenager may affect the brain as much as many hours of practice as an adult. But it also coincides with a time in life when youths are most apt to experiment with drug and alcohol use, "which may also impact which brain circuits get eliminated and which get enhanced." Researchers say inhalants pose a particular threat to brain development and the future.

The sudden growth in the thinking part of the brain peaks at age 11 for girls and 12 for boys, but continues through the teen years. Whether the timing is related to sexual maturation and increase in hormones is a source of some speculation.

There's no doubt that memory and cognitive ability can be influenced by hormone levels.

Listen up

And speaking of hormones and gender, think about this: Last week, scientists at Indiana University School of Medicine released a report that says if you think men and women listen differently, you're right. Real-time studies of the brains of men and women who were actively listening shows that the process only involves a man's left hemisphere, while women "listen" with both sides of their brains.

The research, presented at the annual meeting of the Radiological Society of North America, doesn't say whether that difference results because men don't have to use both sides of their brains to listen and women do, or whether listening in half or both sides of the brain yields different results.

That follows a study five years ago by Yale Univesrity that found women use both sides of their brain to read or do other verbal tasks, while men, again, use only parts of their left hemisphere.

While researchers don't know what it means, they believe that may be why girls usually speak sooner than boys, read more easily and have fewer learning disorders.

Decline not inevitable

Scientists are just beginning to understand what goes on in the aging brain. And belief that neurons inevitably die off, never to be replaced, is wrong. The Dana Foundation reports that the brain loses relatively few nerve cells. With further understanding of how the brain ages, it may be possible to use medications to stop that decline.

An aging brain can develop new neural pathways. And there are lifestyle choices that influence that.

A decadelong study of senior citizens, published in the Journal of the American Medical Association, found that, absent the known gene for Alzheimer's disease or significant signs of diabetes or atherosclerosis, which can both have serious consequences for the brain, lifestyle choices can influence "successful aging."

Education level seems to impact how well the brain will maintain its function. Mental exercise slows decline.

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In "The Aging Brain," the Dana Foundation says that reducing stress, having a good attitude and exercise increase the brain's reserves.

That doesn't mean the brain is impervious to decline. Some areas, including the part of the frontal lobe associated with memory, judgment and planning always seems to decline somewhat with age. Researchers are studying whether certain drugs might substitute for failing neurotransmitters and restore cognitive function.

Developing medications is a large part of brain research. Medication that adjusts levels of serotonin, a substance in the brain that acts as a messenger, is used to treat depression. Other medications counter chemical imbalances involved in mental illness. Large doses of a medication called methylprednisolone, given withing a few hours of spinal cord inury, improves functional recovery, while the first of its kind treatment for stroke, t-PA, also given quickly, can improve stroke recovery.


E-MAIL: lois@desnews.com

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