Brain

Brain

Back in those heady, science-will-save-the-world days of the Industrial Revolution, inquiring medical minds left little to chance. They studied germs and gerbils, bacteria and birds, mold spores and monkeys--anything they could slice into little pieces and slip under a microscope.

When opportunity presented itself, they even studied each other''''s inquiring minds. Fun-loving groups like the Mutual Autopsy Society of Paris scoured the Western Hemisphere for the brains of the eminent. When they got hold of one, they weighed it, measured it and compared brain size with intelligence.

This society along with other organizations with similar pursuits found that brains were like zucchini--bigger didn''''t mean better. Napoleon III, the negligible nephew of Napoleon Bonaparte, weighed in with a 1,500-gram brain--17 percent larger than poet Walt Whitman''''s 1,282-gram offering. (Poor Walt: After the weigh-in a shaky member of the American Anthropometric Society dropped the great poet''''s brain on the floor, where it splattered like an egg.)

Crazy King Ludwig II housed a 1,349-gram brain inside his Bavarian skull, besting Albert Einstein, Mr. Theory of Relativity himself, by almost 10 percent. History fails to even record the size of Abraham Lincoln''''s brain--perhaps, some historians say, because records were lost during the assassination mayhem, or scientists found it shockingly small for such a statesman.

If size doesn''''t matter, what does? Above all, your brain''''s care and feeding. Nourish it with the right nutrients, give it enough mental stimulation, get enough physical exercise, and it will probably serve you well--no matter what its size--for decades to come.

"People used to think there was nothing they could do to help their brains," says Douglas Herrmann, Ph.D., memory researcher at the National Center for Health Statistics and author of Super Memory. "But that''''s not true. Nutrition and other factors can improve memory and other brain functions. You can definitely make a difference."

Divvying the Duties

The brain is the business end of the body''''s central nervous system. It takes electrical impulses from nerve endings all over the body, sorts out what the body is trying to say and then transmits messages back through the nerve network, telling the body what to do. Sweat. Sneeze. Breathe.

Of course, the brain does much more than that. It''''s responsible for higher functions such as language, creativity and logic. It stores memories. It interprets impulses from our eyes so that we can see. Though it only weighs about three pounds--2 percent of your body weight--the old noodle uses up 70 percent of all the air you breathe and the food you eat.

Brains are divided into a number of interconnected parts, each of which controls different body functions. The cerebrum, the largest chunk of the brain, takes care of distinctly human traits such as reasoning and intellect. Most of our reasoning takes place in the part of the cerebrum called the cortex--the gray, folded layer of skin that looks like a walnut shell and covers the surface of the brain. The cortex takes information from nerves in the body and directs voluntary movements, like bending your fingers or walking. It''''s also where you perceive the senses; the cortex sorts out impulses from your eyes, ears, nose, tongue and skin and figures out colors, sounds, smells, tastes and feeling. The cortex appears to house memories, too, storing many of them in the areas called temporal lobes.

In the Main Brain

Deep under the cortex lies the thalamus. This area serves as a cerebral distribution center, routing information from along sensory pathways to the proper part of the cortex. The thalamus, in fact, seems to be just a dumber version of the cortex. It can sense pain, for example, but it can''''t tell the difference between pain from a paper cut and pain from a wildcat attack.

Even deeper in the brain is a cluster of structures such as the almond-shaped amygdala that make up the limbic system--the ancient seat of our darkest, most secret emotions. Though limbic means, literally, the peripheral limits of our system, this area controls many of the everyday functions such as digestion, heartbeat and smell as well as many aspects of emotion and behavior.

As for the rest of the brain, it handles run-of-the-mill, any-mammal-can-do-it stuff. The brain stem--which includes sections called the midbrain, pons and medulla oblongata--controls activity in the heart, blood vessels and respiratory system. The tiny hypothalamus, located at the base of the cerebrum, controls body metabolism, temperature, blood sugar levels, appetite and sexual arousal. The cerebellum orchestrates muscle action; once your cortex orders a movement, the cerebellum tells which muscles to move and how.

Nourish Your Neurons

The average human brain contains about 100 billion nerve cells, each with several tiny branches of communication called dendrites that allow fellow cells to communicate with each other. The point at which these dendrites meet is called a synapse. Your brain can make 100 billion separate connections with itself--a nearly infinite number of possible combinations.

Sounds like a lot, doesn''''t it? But brain cells don''''t replenish themselves like skin cells. Constant stress or alcohol abuse can destroy some of that treasure. Then, late in middle age, we all start to lose neurons--the brain cells that send signals to each other. (Other brain cells, called glials, support and repair the neurons.)

Good food and exercise can fatten our brain cells and lengthen dendrites. These branchlike pieces of neuron collect and help process information. But thickening a wig of dendrites isn''''t the same thing as growing a whole new cell. Actually, most scientists thought building new brain cells was something that ceased at birth. That was before the canary scam.

Bird Clues to Brain Work

Back in the 1930s the so-called canary scam started a chain reaction of neural curiosity in a nest of brain researchers at Rockefeller University and Cornell University Medical College in New York. A pet store owner knew why the caged bird sings: Males sing, females don''''t. So he injected his female birds with testosterone. They sang. They sold--but they stopped singing as soon as the hormone wore off.

Intrigued by the effect of testosterone, in the early 1980s the scientists at Rockefeller University and Cornell University Medical College found that new neurons lay at the heart of the female''''s testosterone-stimulated song. In subsequent studies Cornell researchers identified precursor cells--primed to create new neurons--in rat brains and in human brains. Later on, the researchers managed to grow new neurons from those cells in a petri dish.

"We can grow hundreds of neurons at a time that way," says Steven A. Goldman, M.D., Ph.D., associate professor of neurology at Cornell and attending neurologist at New York Hospital in New York City. "But we need to grow tens to hundreds of thousands if we''''re going to even think about dealing with brains damaged by stroke or degenerative disease," such as Alzheimer''''s, Parkinson''''s and multiple sclerosis, he adds. "We don''''t even know whether they''''ll be useful in clinical repair. That would be years off, but that''''s the hope."

After engineering those first neurons, Dr. Goldman and his colleagues found out that the truly creative sex hormone wasn''''t testosterone but estrogen. "In bird brains and perhaps in human brains, too, right underneath the areas that generate new brain cells--just a few cells away--is an area where testosterone gets converted to estrogen. And the estrogen causes other cells in the immediate vicinity to make a substance that allows the new neurons to survive--in its absence, they die."

"Estrogen also appears to protect neurons in women, too, in a variety of degenerative brain diseases," Dr. Goldman adds. So the brain may be a beneficiary of hormone replacement therapy--the kind described beginning on page 231.

Gender Differences

Hormones aren''''t the only sex-related discoveries that brain researchers have been making. They know that the fetal brain of the female develops faster than that of the male. And they''''ve found actual scientific data to back up the argument that men and women really are from different planets when it comes to brain function. Among the gender differences: The corpus callosum, which is the bridge connecting the right and left hemispheres of the brain, is bigger in women than it is in men. And brain scans that reveal "thinking" activities show that women tend to use both parts of their brains, while men weigh in more heavily on just one side.

Another difference is that while men''''s brains are bigger by about 10 percent, women have 11 percent more neurons, densely packed into the layers that allow us to understand language and recognize melodies in music and tones in speech. "Women seem better at verbal memory and fluency," says Ruben Gur, Ph.D., professor in the Department of Psychiatry at the University of Pennsylvania in Philadelphia and director of the University''''s brain behavior laboratory. "But men do better at almost any spatial task, like reading maps, as long as it doesn''''t involve memory. They also do better at any motor task, like finger tapping."

Dr. Gur and his wife, Raquel Gur, M.D., Ph.D., professor of psychiatry and neurology and director of the neuropsychiatry section in the Department of Psychiatry at the University of Pennsylvania in Philadelphia, are both neuroscientists, and they started studying sex differences in brains because they were piqued by their own contrasting temperaments. For a while their research didn''''t reveal many brain differences. In men and women, scans of the cerebrum, cerebellum, cortex and lobe showed mostly similarities.

Differences only showed up when the Gurs probed deeper--into the brain''''s limbic system, where so many promptings of emotion and behavior arise. In men the most primitive part of that system, which governs action and aggression, was highly active and lit up like a firecracker when imaged with a method that measures how much energy is consumed by brain regions. In women it was the most highly evolved area, the cingulate gyrus, that glowed brightest. In that limbic region an emotion like anger prompts a look or a word, not a punch.

More between the Sexes

Given these brain differences, what can women and men do to connect with each other? Here are some hints from researchers.

Spell it out. In one interesting experiment, the Gurs tested how men and women read facial moods. With groups of each sex, the Gurs displayed photographs of men and women with happy and sad faces. They discovered what every woman knows--men have a hard time reading a woman''''s sad expression.

The implications? Since men aren''''t so good at reading signals, such as a frown or pursed lips, the sexes need to talk about disturbances and disagreements. You can''''t assume a man will automatically understand an expression that--to you--conveys your emotions very clearly.

"If I talk to someone who doesn''''t answer, I''''ll think he''''s rude--but not if I know he''''s deaf," observes Dr. Ruben Gur. "Men have a very hard time recognizing sadness in women. And now that women know, maybe they won''''t attribute that lack of response to a lack of caring. Recognizing our differences may help rather than hinder us."

Write down directions. If women excel at the subtleties of emotion, men tend to excel in spatial matters. They may not be able to read faces, but in general, they sure can read maps.

If you tend to be frustrated by maps, it''''s more likely you''''ll prefer written directions, especially if they include visual landmarks like: "Turn left at the church on Main Street, then right at the light."

Keep reminding him. Learning faces is a spatial task involving memory that men don''''t do well, says Dr. Ruben Gur. So if you find you have to keep introducing your husband to your friends, don''''t get testy. Just help him along: "You remember Meredith--she is the one who lives next to the post office."

Despite these general differences, however, research shows that both men and women can get better at using the less-developed areas of their brains. Those dendrites can be developed. Besides, there are many exceptions to the general observations of gender differences. Some male brains act more like females''''--and some women''''s brains act more like men''''s.

Pumping Up the Power

While we can''''t grow new neurons in our lifetime, we can usually promote optimal function of the ones we have. One way is to boost the levels of zinc--the memory mineral found in beef, beans and oysters, says James G. Penland, Ph.D., research psychologist with the U.S. Department of Agriculture''''s Grand Forks Human Nutrition Research Center in North Dakota. The nutrient boron--in peanuts, raisins and leafy vegetables--appears to be good for memory, too, and also for attention and motor skills. Smart friends are also good food for the brain, since it''''s been shown that stimulating conversation also stimulates your dendrites to grow.

But the richest Miracle-Gro for the garden of your brain is probably exercise. Studies of people who exercise keep showing links between physical activity and mental ability. These links have been related to substances called nerve growth factors that have been studied by Carl W. Cotman, Ph.D., professor of psychobiology and neurology and director of the Institute for Brain/Aging and Dementia at the University of California, Irvine.

Conducting animal studies, Dr. Cotman put running wheels in rat cages and observed the rodents'''' behavior. He found that the rats assumed individual exercise routines, just like humans do. Some rodents proved to be couch rats, some were marathon rats and some were runaholics. But many settled down naturally to an hourly run a day.

To study the effects of exercise, Dr. Cotman measured the rats'''' levels of a particular type of nerve growth factor that makes neurons flourish. The rat racers'''' levels of nerve growth factor turned out to be higher than levels found in couch-potato rats.

"But the increases didn''''t show up just in the motor areas of the brain. They showed up in the brain structures for cognition, learning and memory. That was a pretty exciting surprise," he says.

The lesson? "What we think is that--at a minimum--exercise makes brain cells healthier, work better and probably resist minor insults like a minor stroke. My guess is that the activity should be something not terribly long, but consistent--I''''m not sure it means every day. Some rats that seem to naturally run about an hour a day show an increase," says Dr. Cotman.

Listen Up--Then Smell the Lemons

The next time you have to work on a budget or balance your checkbook, slip some Mozart in your headphones. Specifically, "Sonata for Two Pianos in D Major, K. 448."

Researchers at the University of California, Irvine, played a recording of that sonata for 36 college students, then gave the students an IQ test measuring abstract reasoning. The students who heard the music scored eight to nine points higher than those who studied in silence. "Listening to a complex and highly patterned piece of music acts as a ''''warm-up'''' for the mind, which could be good for high-level mathematics," says Frances H. Rauscher, Ph.D., research psychologist at the University of Wisconsin-Oshkosh who specializes in the effects of music on intelligence.

In addition to music, certain fragrances might make it easier for you to think more clearly and help reduce mistakes. "You can change brain frequencies with smell," says Alan Hirsch, M.D., psychiatrist, neurologist and neurological director at the Smell and Taste Treatment and Research Foundation in Chicago.

Japanese researchers have discovered that air scented with a lemon spray decreases errors among workers by 54 percent. Other fragrances also reduced goofs, though not as sharply. Jasmine cut mistakes by 33 percent, lavender by 20 percent. Lavender induces a more relaxed state so you can think more clearly, says Dr. Hirsch. As for jasmine, Dr. Hirsch notes that it has the ability to excite--even in concentrations so low you wouldn''''t know it''''s there--resulting in quicker thinking. But Dr. Hirsch found that the odor that has the greatest effect on the speed of learning is a mixed floral scent.

The Wisdom of Age

Does your brain slow down as you age?

Some studies in this fresh area of research indicate that the brain is like a muscle--it seems to get stronger with use. While it may take an older person somewhat longer to learn a new computer system or memorize French idioms, we can keep lots of brain power into our eighties and beyond. You might not make a good computer analyst at age 75, but a superior court judgeship isn''''t out of the question. Unless you develop a brain disorder such as Alzheimer''''s or have a serious stroke, your brain can continue to function at a high level right into and through old age, according to Dr. Herrmann.

Here are some tips to keep that gray matter going.

Get your Bs daily. Vitamin B₆ helps your body create neurotransmitters--chemicals that allow brain cells to fire off messages to one another. In 1992 a study of 38 elderly Dutch folks found that a 20-milligram daily supplement of B₆ could help improve long-term storage of memories. That''''s ten times the federal government''''s recommended Daily Value of 2 milligrams, so you wouldn''''t want to take that much regularly without consulting your doctor.

Your best bet, according to Dr. Herrmann, is to eat a balanced diet containing lots of fruits and vegetables. Since freezing and processing vegetables can rob them of 15 to 70 percent of their B₆ content, you definitely want fresh produce whenever possible. Other super sources of B₆ include chicken, fish and lean cuts of pork.

Use it or lose it. Flex your brain as well as your body. Researchers have found that people with college educations who remain mentally active throughout their lives have 40 percent longer dendrites than less-educated, less-challenged people. The longer the dendrites, the more information you can receive and understand.

But you don''''t really need a diploma to develop those dendrites. Most kinds of mental activity help keep the connections between your brain cells humming, so try continuing education courses at the local college, crossword puzzles or even playing along with television game shows, suggests K. Warner Schaie, Ph.D., professor of human development at Pennsylvania State University in University Park.

Dr. Schaie''''s research team found only one game that was not too helpful: bingo. Unless you play about 20 cards at once, he says, you''''re better off guessing along with Vanna on Wheel of Fortune.

Keep the pressure down. High blood pressure is a three-prong problem. It''''s been implicated in 40 percent of brain-busting strokes. It slows down your thought processes and appears to impair short-term memory. Worst of all, a study of 35 people between ages 51 and 80 showed that high blood pressure appears to cause permanent structural changes and tissue loss in the brain. One of the authors of the study, Declan Murphy, M.D., senior lecturer and consultant psychiatrist at Bethlem Royal Hospital in Kent, England, says that this could over time cause problems with memory, language and sense of direction.

Make sure you get your blood pressure checked by a doctor or health professional at least once a year. And then follow your doctor''''s advice to help keep your blood pressure under control.

The Price We Pay

Complexity hardly ever comes cheap. With billions of neurons buzzing bounteously in your brain, things sometimes go very, very wrong. Even a simple blow to the head can erase your command of the English language and have you fluent in a language you haven''''t spoken in decades. For example, an 80-year-old woman can suffer severe brain trauma that erases 70 years'''' worth of English language and begin communicating in the native Italian she spoke as a young girl.

A more common mystery is why you sometimes feel dizzy or faint. That giddy, light-headed, unsteady sensation can be caused by something as simple as a glitch in your sensory network or disturbances in the movement of fluid--you bend over or stand up too quickly, and you haven''''t given your blood enough time to get to your brain. Severe anemia, high blood pressure, low blood pressure, low blood sugar and side effects from drugs can also dizzy you. When it comes on suddenly and is accompanied by chest pains, rapid heart beat, blurred vision or numbness, dizziness can also be a warning sign for stroke.

Sometimes dizziness precedes fainting--the loss of consciousness that could come from interrupted blood flow to the brain. If that happens often, you should have an evaluation by your doctor or internist. But the more usual causes are circulatory problems.

Actual brain disorders range from infections such as meningitis to genetic breakdowns such as Down''''s syndrome and mental conditions such as schizophrenia. "The brain is extremely complicated," says Francis Pirozzolo, M.D., neuropsychologist at Baylor College of Medicine in Houston. "We''''re learning more about it every day, but it continues to puzzle us and frustrate us. Sometimes things go wrong that we just can''''t fix."

The Warning Signs of Stroke Know the warning signs of stroke, says the American Heart Association. The Association provides a doctor-approved list of the most common warning signs. They include: * Sudden weakness or numbness of the face, arm or leg on one side of the body * Sudden dimness or loss of vision, particularly in only one eye * Loss of speech or trouble talking or understanding speech * Sudden, severe headaches with no known cause * Unexplai