"Memory, which the ancient Greeks attributed to a muse and Descartesascribed to 'animal spirits', depends on particular bits of gray matter. Ditto for language, the recognition of familiar faces, the ability to count and read, and many other higher functions. Wipe out one part of the brain and a person speaks fluent gibberish; remove another and he no longer knows his own brother by sight. Brain surgery, strokes, tumors, and head injuries can turn a person into a nonperson, or so it seems. Where, then, is the self?".

The Brain's Got Rhythm
Informs that the brain compromises with the circadian rhythm of the body. How loss of sleep affects cognitive processes; Physiological changes that happened in the body during sleep at night.

Though travelers can now zip through multiple time zones by simply steppingon a plane, their brains may work more slowly once they step off, warns a researcher at the University of Pittsburgh Medical Center. And those of us who don't leave home but do lose sleep may also think more slowly the next day--even if we feel wide awake.

Such effects aren't simply caused by fatigue, says Timothy Monk, Ph.D., but by compromising our bodies' circadian rhythms. When we work against these biological cycles of wakefulness and rest, our cognitive processes pay the price. Monk conducted a study, recently published in the journal Sleep, in which participants were kept awake for 36 hours and given hourly performance tests. Their response times increased at night, and also with every hour that they lost sleep.

"At night, our biological clock goes to work changing our body temperature, heart rate, hormones--changes that may make us think more slowly", he says. In the morning, an upswing in circadian rhythms creates a "second wind" that makes us feel more awake and energetic, even if our brains aren't up to speed.

Unfortunately, our ability to assess how impaired we are is often the first thing to go".People who don't get enough sleep should be aware that their thinking will not be as sharp", says Monk".They should allow extra space between cars if they're driving in traffic, and not cut into safety margins if they're using dangerous equipment.

How Brains Get Wrinkled
Explains theories on the wrinkling of the brain. Theory which cell division is assumed as the basis; Theory proposed by anatomy professor David Van Essen.

For the first six months after conception, a fetus's brain--like itsbottom--is smooth. But during the third trimester of pregnancy the brain's outer layer, the cortex, develops the familiar nooks and crannies that adorn adult brains. The need for this wrinkling is obvious; it's the only way to squeeze a cortex the size of a 12-inch pizza on top of each of the brain's hemispheres.

What's not so obvious is how this scrunching occurs in the first place. Many scientists assume that the explanation lies in cell division; perhaps certain cells in the cortex are programmed to proliferate faster than others, causing the brain's surface to fold. But David Van Essen, Ph.D., a professor of anatomy and neurobiology at Washington University in St. Louis, has proposed a different theory. He notes that neurons growing in a petri dish develop tension along their axons, the long appendages by which they send messages. When manY of these cells run in parallel paths through the brain, Van Essen suggests in a recent issue of Nature, the combined tension distorts the surface of the cortex, just as the shape of a rubber hand changes when you pull on it.

The Brain Breaks For Sexual Puns
Why the brain takes it slow when processingsexual information.

When it comes to processing sexual information, the brain likes to take it slow, says James Geer, Ph.D. The Louisiana State University psychologist found that double entendres--words or phrases with more than one meaning--took longer to respond to when they had an erotic component.

Geer had subjects read a series of sentences, each including a word that could be sexual or not, depending on context. They were then shown a string of letters and asked whether it was nonsense or an actual word. When the initial sentence or word was sexual, men took longer to complete the task than when what they'd read was neutral--and women were slower still, Geer reports in the Archives of Sexual Behavior. It seems that in language, as in life, sex makes things complicated".You only have so many mental resources to apply to any task", he says".If the task generates an emotion, this uses up some of those resources, and work on the task is slowed down". Sexual inhibitions also contribute to the delay: The more "socially unacceptable" subjects considered a word, the longer they took to react.

In responding to risque language, says Geer, we may fear making an inappropriate reply that will embarrass us. This danger is especially apparent to women, who are socialized to be cautious in sexual matters. So, Geer says, we put mental processing "on hold" for a moment, while we think of just the right thing to say.

The Busy Brain
Focuses on a study which suggests that lifelong mental activity may partially halt the process of brain atrophy which occurs with aging. How a team of psychology professors gave their fellow academics a five-part mental workout in order to test whether a busy brain can ward off deterioration; Comparison of results from young, middle-aged, and senior faculty participants.

USE IT OR LOSE IT !

If the human body came with an owner's manual, one of the primary recommendations would be use it or lose it: inactive muscles wither, underexercised hearts grow feeble. Aging brains atrophy as well--but a recent study suggests that lifelong mental activity can partially halt the process.

To test whether a busy brain wards off deterioration, a team of psychology professors put their fellow academics through a five-part mental workout and compared how young, middle-aged, and senior faculty performed.

First, the bad news. The senior faculty's performance on a reaction-time test (pressing a key as soon as a computer flashed the word "go") demonstrated that neurons slow down as they age--and studying particle physics for 40 years won't help. Older professors also had more trouble matching pairs of names or faces.

But the over-60 crowd fared just as well as their younger col-leagues--and far better than non-professors of the same age--when asked to remember details of an informational paragraph about tribal cultures or atmospheric gases. And they did an equally fine job remembering the order in which 15 words or pictures were presented. Performance on both tests normally sags with age.

The final test, in which subjects pointed to previously unchosen patterned squares in a continually reshuffled array, produced a split decision. Older professors made more errors than the juniors and just as many mistakes as same-age controls. But they improved slightly on a second trial, while performance of the older controls declined.

"No matter how mentally active you are, you're going to slow down", says University of California at Berkeley psychologist Arthur Shimamura, Ph.D. But a brain kept busy may better compensate for age-related decline.

The Busy Brain Blues
Provides information on the research of Waynes Drevets of the University of Pittsburg Medical Center about the amygdala, a small brain region that plays a central role in emotional learning and behavior. Effects of severe depression to the brain; Implication of his research about anti-depressants; Implication of his research about depressive disorders.

Severe depression often paralyzes its sufferers with a sense of overwhelminglistlessness and lethargy At the same time, however, some parts of the depressive's brain may be working overtime, reports Wayne Drevets, M.D., of the University of Pittsburgh Medical Center.

Drevets presented his research on the amygdala--a small brain region that plays a central role in emotional learning and behavior--at the annual meeting of the Society for Neuroscience in October. He used positron emission tomography, or PET, to measure the glucose metabolism of the amygdalas of people with different types of depression. Abnormally high metabolism, says Drevets, would indicate that the cells in that region are especially busy communicating with each other, perhaps producing exaggerated emotional states like obsessive ruminations and panic attacks. And indeed, he found this heightened activity in the brains of two groups of patients: those with manic-depressive illness, and those with the kind of depression that runs in families and is thought to be caused, at least in part, by genetic factors.

In addition, Drevets' research fits another piece into the puzzle of how antidepressants work. Scientists have long been aware that the drugs reduce amygdala metabolism, but didn't know until now that this result is far more than a side effect.

The Shy Brain
What's unique about the nervous system of a shy person?

We all take time to get used to (or habituate to) a new stimulus (a job interview, a party) before we begin to explore the unfamiliar. After all, a novel stimulus may serve as a signal for something dangerous or important. But shy individuals sense danger where it does not exist. Their nervous system does not accommodate easily to the new. Animal studies by Michael Bavis, Ph.D., of Yale University, indicate that the nerve pathways of shyness involve parts of the brain involved in the learning and expression of fear and anxiety.

Both fear and anxiety trigger similar physiologic reactions: muscle tension, increased heart rate, and blood pressure, all very handy in the event an animals has to fight or flee sudden danger. But there are important differences. Fear is an emotional reaction to a specific stimulus; it's quick to appear, and just as quick to dissipate when the stimulus passes. Anxiety is a more generalized response that takes much longer to dissipate.

Studies of cue conditioning implicate the amygdala as a central switchboard in both the association of a specific stimulus with the emotion of fear and the expression of that fear. Sitting atop the brain stem, the amygdala is crucial for relaying nerve signals related to emotions and stress. When faced with certain stimuli--notably strangers, authority figures, members of the opposite sex--the shy associate them with fearful reactions.

In contrast to such "explicit" conditioning is a process of "contextual" conditioning. It appears more slowly, lasts much longer. It is often set off by the context in which fear takes place. Exposure to that environment then produces anxiety-like feelings of general apprehension. Through contextual conditioning, shy people come to associate general environments--parties, group discussions where they will be expected to interact socially--with unpleasant feelings, even before the specific feared stimulus is present.

Contextual conditioning is a joint venture between the amygdala and the hippocampus, the cell cluster near the amygdala, which is essential to memory and spatial learning. Contextual conditioning can be seen as a kind of learning about unpleasant places.

But a crucial third party participates in contextual conditioning. It's the bed nucleus of the stria terminalis (BNST). The long arms of its cells reach to many other areas of the brain, notably the hypothalamus and the brain stem, both of which spread the word of fear and anxiety to other parts of the body. The BNST is principally involved in the generalized emotional-behavioral arousal characteristic of anxiety. The BNST may be set off by the neurotransmitter corticotropin releasing factor (CRF).

Once alerted, the hypothalamus triggers the sympathetic nervous system, culminating in the symptoms of inner turmoil experienced by the shy--from rapid heartbeat to sweaty paleness. Another pathway of information, from the amygdala to the brain stem, freezes movement of the mouth.

The shy brain is not different in structure from yours and mine; it's just that certain parts are more sensitive. Everyone has a "shyness thermostat", set by genes and other factors. The pin-pointing of brain structures and neuro-chemicals involved in shyness holds out the promise that specific treatment may eventually be developed to curb its most debilitating forms.

Brain Teasers
Focuses on persons with impairment on their right anterior frontal lobes. Discovery of the part of the brain responsible for sense of humor; Details on the study conducted at the Baycrest Centre for Geriatric Care in Toronto, Ontario; Information on how patients understood jokes.

HUMOR !

Did you hear the one about the girl who couldn't take a joke? She had no frontal lobes. All kidding aside, researchers have discovered that a specific area of the brain is largely responsible for our sense of humor.

Not all funny bones are created equal; a crack that tickles some people's ribs may make others roil their eyes. Prathiba Shammi, Ph.D., and Donald Stuss, Ph.D., have found that patients with impaired right anterior frontal lobes--a part of the brain that processes irony, nonliteral interpretation and problem-solving--understand only obvious slapstick jokes and not more complex question-and-punch-line riddles. This particular brain structure may therefore influence what we find funny.

In this study, conducted at the Baycrest Centre for Geriatric Care in Toronto, patients deemed a list of supposedly humorous verbal statements less funny than did nonimpaired individuals. When asked to choose which of four answers would be the likely punch line to a joke, patients were also more likely to pick a bizarre non sequitur like "Your nose is too big for your face, boss!" which didn't fit with the riddle. The researchers report in the journal Brain that while patients understood that jokes should have a surprise ending, they were unable to detect the answer that made reference to the joke itself, choosing instead one that was obviously amusing on its own.

Clearly, comedy is not just a laughing matter--getting it requires some serious mental skill.

Brain Gain
Focuses on a study which helped confirm research suggesting that the adult brain is more malleable than neuroscientists thought. Details on the study which examined the brains of several men with magnetic resonance imaging to determine whether brains actually gain tissue over time; Findings of the study.

AGING !

Smug teens may think they have, on average, more brain cells than adults have. But now, brain researchers in Arkansas have given a nod to the middle-aged. One kind of brain tissue actually increases in adults.

A new study in the Archives of General Psychiatry helps confirm recent research suggesting the adult brain is more malleable than neuroscientists thought. Some researchers believe the adult brain adds small numbers of cells continuously. But others are cautious about the possibility of forming new brain cells with good reason--they might disrupt firmly established neural pathways.

To see whether brains actually gain tissue over time, George Bartzokis, M.D., of the Veterans Administration hospital in Little Rock, examined the brains of 70 men, ages 19 to 76, with magnetic resonance imaging. The images showed the areas of gray matter, outer sections associated with functions such as vision and reasoning, and white matter, the layer of nerve-rich cells that connect different brain regions. Bartzokis found that the gray matter steadily declined with age, confirming the old model of the brain. But he discovered that the connecting white matter actually grew until his subjects reached their late forties. This means adult brains work faster than adolescent ones.

"The idea that once we reach the magical age of 18 we are adults is wrong", says Bartzokis.
"There are only two phases: Development and degeneration"

The Myth Of The Aging Brain
Reveals the people in the greatest danger of cognitive decline, according to studies. Older adults that are not doomed to senility; Suggestion for preventing age-related memory loss.

MEMORY !

What people fear most about aging is losing their mental acuity. Now, there's good news for elderly folk in good health: They will likely enjoy their golden years with memories intact.

People in the greatest danger of cognitive decline include those with diabetes, cardiovascular disease or a gene called apolipoprotein E e4 (APOE e4), which recent studies have linked to Alzheimer's disease, says Mary Haan, M.P.H., director of the Center for Aging and Health at the University of California-Davis. Elderly people with these diseases can lose their short-term memory up to eight times as fast as their healthier counterparts, she reports in the Journal of the American Medical Association. But older adults with family histories of Alzheimer's disease or a high risk of cardiovascular disease aren't doomed to senility: Haan believes that they can fend off age-related memory loss by exercising regularly and eating a healthful diet.

The Aging Brain
Are you forgetful? You may be under too much pressure.

It's one of aging's many ironies: those who worry about getting older may be hastening their own mental decline. Research shows that stress makes the brain age more quickly and forget more readily.

The study, published in Nature Neuroscience, is the first to show that cortisol, a hormone secreted in response to stress, can cause healthy elderly adults to perform poorly on memory tasks. It appears to do so by reducing the size of the hippocampus, a brain structure critical to short-term and spatial learning.

Sonia Lupien, Ph.D, a neuroscientist at McGill University in Canada, and her colleagues monitored a group of elderly people for five years to examine the effects of cortisol on their brains. She found a shrinking of the hippocampus in subjects who had higher, but still normal, levels of cortisol, which continued to rise over the five-year period. In subjects whose cortisol levels were normal and declined with time, however, the hippocampus stayed the same size.

When asked to recall pictures of common objects or navigate a maze seen the previous day--tasks that depend heavily on the hippocampus--the high-cortisol group took longer than their low-cortisol counterparts.

Those with impaired memories also reported feeling more stressed than did other subjects. More crucial than the number of worries they faced, says Luplen, was how they dealt with the pressures. People with elevated cortisol levels, she contends",are more reactive to their environment"--and less in control of their troubles.

Neuroscientists now hope to determine the level at which cortisol first begins to affect mental functioning. Observes Lupien: "We're at the frontier of preventing pathological memory loss".

Ultrasound: A New View Of The Mind
Informs the use of ultrasound in monitoring the movement of blood through the brain. How the process works; Advantage of ultrasound over magnetic resonance imaging (MRI) and positron emission tomography (PET) scans; Future experiment with the use of ultrasound.

Your doctor may have used ultrasound to inspect your arteries for blockage orto examine your unborn baby. But scientists are now using the technology to trace a more fleeting phenomenon: thought itself".Most people are familiar with the use of ultrasound to provide pictures of body structure", says Albert Roberts, Ph.D., of Catawba College in North Carolina".But ultrasound can also be used to monitor the movement of blood through the brain".

Roberts is a pioneer in neurosonography, in which high-frequency sound waves are sent into the brain and reflected by the brain's red blood cells. Unlike magnetic resonance imaging (MRI) and positron emission tomography (PET) scans, which provide only a snapshot of the brain, ultrasound allows researchers to "see" brain activity as it's happening.

Roberts says the technology may one day be used to measure impairment and recovery in the brains of stroke and coma victims, and to track changes in blood flow in response to medications. In Roberts' next research project he will use ultrasound to investigate the effects of a particularly common drug: caffeine.

Blood flow velocities to various parts of the brain can be measured by ultrasound.