By Rob Stein, Washington Post Staff Writer With a good night's rest increasingly losing out to the Internet, e-mail, late-night cable and other distractions of modern life, a growing body of scientific evidence suggests that too little or erratic sleep may be taking an unappreciated toll on Americans' health. Beyond leaving people bleary-eyed, clutching a Starbucks cup and dozing off at afternoon meetings, failing to get enough sleep or sleeping at odd hours heightens the risk for a variety of major illnesses, including cancer, heart disease, diabetes and obesity, recent studies indicate. "We're shifting to a 24-hour-a-day, seven-day-a-week society, and as a result we're increasingly not sleeping like we used to," said Najib T. Ayas of the University of British Columbia. "We're really only now starting to understand how that is affecting health, and it appears to be significant." A large, new study, for example, provides the latest in a flurry of evidence suggesting that the nation's obesity epidemic is being driven, at least in part, by a corresponding decrease in the average number of hours that Americans are sleeping, possibly by disrupting hormones that regulate appetite. The analysis of a nationally representative sample of nearly 10,000 adults found that those between the ages of 32 and 49 who sleep less than seven hours a night are significantly more likely to be obese. © 2005 The Washington Post Company

Keyword: Sleep; Obesity
Link ID: 8015 - Posted: 06.24.2010

By Michael S. Gazzaniga Any child can tell you that some people are smarter than others. But what is the difference between the brain of a Ph.D. student and the brain of the average Joe? If we can figure that out, then a bigger question follows: Is it ethical to turn average Joes into geniuses? Evolutionary theory suggests that if we are smart enough to invent technology that can increase our brain capacity, we should be able to use that advantage. It is the next step in the survival of the fittest. As noted psychologist Corneliu Giurgea stated in the 1970s, "Man is not going to wait passively for millions of years before evolution offers him a better brain." That said, gnawing concerns persist when it comes to artificially enhancing intelligence. Geneticists and neuroscientists have made great strides in understanding which genes, brain structures and neurochemicals might be altered artificially to increase intelligence. The fear this prospect brings is that a nation of achievers will discard hard work and turn to prescriptions to get ahead. Enhancing intelligence is not science fiction. Many "smart" drugs are in clinical trials and could be on the market in less than five years. Some medications currently available to patients with memory disorders may also increase intelligence in the healthy population. Likewise, few people would lament the use of such aids to ameliorate the forgetfulness that aging brings. Drugs that counter these deficits would be adopted gratefully by millions of people. © 1996-2005 Scientific American, Inc.

Keyword: Intelligence; Learning & Memory
Link ID: 8014 - Posted: 06.24.2010

Researchers have found provocative evidence that the brain dysfunction that underlies epilepsy may also determine whether people are at risk for suicide. The study, published online October 10, 2005 in the Annals of Neurology (www.interscience.wiley.com/journal/ana), also suggests that depression and suicide may have different brain mechanisms. "For reasons that are not understood, depression both increases the risk for developing epilepsy and is also common among people with epilepsy who experience many seizures," said lead author Dale C. Hesdorffer, Ph.D., of the Gertrude Sergievsky Center at Columbia University. It has commonly been assumed that the difficulties associated with living with epilepsy could provoke depression, and in some cases, an increased risk of suicide, the authors write. But is harder to explain the opposite findings, that people who develop depression have a higher risk of later experiencing a first seizure. While neuroscientists have postulated overlapping brain systems for depression and epilepsy, this evidence is still preliminary. In the present study, the researchers attempted to define more clearly the relationship between depression, suicide, and epilepsy.

Keyword: Depression; Epilepsy
Link ID: 8013 - Posted: 10.10.2005

A student who had pioneering surgery for epilepsy says her life has turned around since the treatment. Natalie Seed, 21, a forensics student at Lincoln University, had an implant inserted near her collarbone to stimulate a nerve in the neck. By sending regular, tiny pulses of electrical energy to the brain, the device can help prevent a seizure. Natalie, from West Yorkshire, said her seizures had dropped from about 12 a day to two a week since the surgery. "It neutralises the build up of energy in your brain which causes the seizure and is operated magnetically," the student from Featherstone said. "If you swipe a magnet that you carry around with you across the box it gives a higher stimulation instantly that neutralises the seizure and reduce the severity and length of it." One side effect is that her voice gets lower and husky when the magnet is swiped. She was six when she fractured her skull in her school playground - an accident which probably triggered her severe epilepsy. By the age of nine, she was having twelve seizures a day. Almost 456,000 people in the UK suffer from epilepsy, making it the second most common neurological condition after migraines. (C)BBC

Keyword: Epilepsy
Link ID: 8012 - Posted: 10.08.2005

By Shankar Vedantam, Washington Post Staff Writer Warnings that drugs such as Prozac, Paxil and Effexor can increase suicidal behavior in some children have resulted in a nearly 20 percent drop in U.S. pediatric prescriptions of the widely used antidepressants and have triggered deep concerns about the quality of current data on psychiatric drugs, doctors and regulators said. The unprecedented fall of what were once considered wonder drugs comes as a series of taxpayer-funded analyses have systematically undermined the claims of industry-funded drug trials, raising thorny questions about the ways in which psychiatric drugs are being tested, marketed and used. No one knows the consequences of such a steep decline in children's drug prescriptions: Critics of the drugs say regulators ought to crack down further, as British health authorities did last month, but many American psychiatrists are worried that reduced access to medications could cause an increase in suicide as a result of untreated depression. As with many disputes over these and other psychiatric drugs, opinions are more readily available than definitive data. The fundamental problem, many experts said, is that there are not enough systematic long-term studies about psychiatric drugs. © 2005 The Washington Post Company

Keyword: Depression; Development of the Brain
Link ID: 8011 - Posted: 06.24.2010

When you spot a celebrity on a magazine cover, your brain recognizes the image in an instant--an effect that seems to occur because of a single neuron. A recent study indicates that our brains employ far fewer cells to interpret a given image than previously believed, and the findings could help neuroscientists determine how memories are formed and stored. Exactly how the human brain works to record and remember an image is the subject of much debate and speculation. In previous decades, two extreme views have emerged. One says that millions of neurons work in concert, piecing together various bits of information into one coherent picture, whereas the other states that the brain contains a separate neuron to recognize each individual object and person. In the 1960s neurobiologist Jerome Lettvin named the latter idea the "grandmother cell" theory, meaning that the brain has a neuron devoted just for recognizing each family member. Lose that neuron, and you no longer recognize grandma. Experts long ago dismissed this latter view as overly simplistic. But Rodrigo Quian Quiroga of the University of Leicester in England and his colleagues decided to investigate just how selective single neurons might be. The team looked at eight patients who each had 64 tiny electrodes implanted in their brains before epilepsy surgery (a procedure to pinpoint the source of their seizures). Many of the electrodes were placed in the hippocampus, an area critical for the storage of long-term memories. © 1996-2005 Scientific American, Inc.

Keyword: Vision
Link ID: 8010 - Posted: 06.24.2010

With, or without us, our world continues to change at an incredible pace. The twentieth century has seen cars getting closer and closer to the supposed futuristic fantasies of the manufacturers of the 1950's; computers that, less than 40 years ago filled a whole office, now sit nicely on each of our desks; scientists are making breakthroughs in fighting diseases that only decades ago hadn't even been identified yet. In order to keep pace with our ever-changing environment we all have to learn to adapt, and as the father of the theory of evolution Charles Darwin declared, adaptation can mean survival. So as a race are we still evolving? It seems that we are. Researchers have shown that mutations, or variants, in two genes thought to regulate brain size have only arisen recently in the long history of evolution of the planet and appear to be spreading quickly in large swaths of the world's population. Armed with this fresh evidence, one researcher argues that our brains are still evolving. "We've caught evolution in action, in the sense that here is a new variant in each one of these two genes that arose very recently," says human geneticist Bruce Lahn, from the University of Chicago and an investigator at the Howard Hughes Medical Institute. "Our findings just added another piece of evidence to the idea of evolution, that as a species we're still evolving, even as a very complex species we're still evolving. We can see that at the level of genes, that is, our genes are still in the process of changing." © ScienCentral, 2000-2005.

Keyword: Evolution; Development of the Brain
Link ID: 8009 - Posted: 06.24.2010

The patient came into the doctor's office in a wheelchair, weighted down by a diagnosis of Parkinson's disease, taking medication for the disorder and insisting she was unable to stand or walk. Thirty minutes later, after jogging down the hallway, she strolled out the door. No Parkinson's patient was she. Rather, she was a perfect example of a person with "fear of falling gait," said neurologist and Parkinson's expert Roger Kurlan, M.D., of the University of Rochester Medical Center. Kurlan has seen enough cases of the condition, where a person is so afraid of falling that the mind actually affects the ability to walk, that he wrote about the disorder in the September issue of Cognitive and Behavioral Neurology to cue other physicians about the condition. In the case reported in the journal, Kurlan describes an elderly woman who had an increasingly difficult time walking. The difficulties began shortly after her husband died, when she tripped and fell, breaking a wrist and bruising her leg. Her inability to walk led her doctor to diagnose Parkinson's disease, and she was prescribed the Parkinson's medication levodopa to treat her symptoms. Despite treatment, she ended up in a wheelchair, unable to walk, and she was sent to Kurlan, an expert in movement disorders like Parkinson's. A thorough physical exam turned up nothing abnormal, but the woman refused to try to stand up on her own, even pushing herself down into her chair as Kurlan and a nurse tried to convince her to attempt to stand up. With enough persuasion, though, and with several people available to help her up, the woman finally did rise.

Keyword: Parkinsons
Link ID: 8008 - Posted: 10.08.2005

Howard Florey Institute scientists in Melbourne have found that fluoxetine (commonly marketed as ProzacŪ) not only improves depression in Huntington's disease, but also improves learning and memory. Dr Anthony Hannan and his team also found that fluoxetine restores the brain's process of neurogenesis - the birth of new neurons - to normal levels, which helps delay the onset of the inherited fatal disease. People with Huntington's disease have progressive motor problems, cognitive deficits (dementia) and psychiatric symptoms (the most common is depression) that usually start to appear in mid-life. There is no cure and death usually results within 10 to 20 years of symptom onset, or faster in the childhood-onset form of the disease. The disease is caused by a mutation in a single gene and when this defective gene is passed from parent to child, 50 percent of the offspring will inherit the disorder, which can be detected by genetic testing. Dr Hannan said this discovery was an important step in developing effective treatments to delay the onset of symptoms and the progression of Huntington's disease. "Now that we've found fluoxetine improves memory problems, or dementia, as well as depression in mice with Huntington's disease, further research can be conducted to see if the drug has the same benefits in humans with the disease," Dr Hannan said.

Keyword: Huntingtons; Learning & Memory
Link ID: 8007 - Posted: 10.07.2005

By Jay Michaelson There was a time when I didn't have a memory. It was the spring of 2001, after I suffered a Grade 3 concussion when a tow truck hit a taxi in which I was riding. For six months, I forgot conversations as soon as they were over, lost track of names and addresses, and often found myself on the street, or the subway, without any idea where I was headed or why. Of course, everyone forgets things: We've all had the experience of walking into the kitchen and then losing track of why we came, or fumbling for the name of someone we've met a dozen times. But this was different. This was a complete erasure of linear time. Every moment was new, without history, and grounded in the past only by the detailed notes I kept for myself. After about six months, the symptoms eventually lifted and my short-term memory returned. I had suffered no retrograde amnesia and should have been back to my "old self." Except that my old self was no longer there. In the six-month space of my memory loss, I had quit my job at the software company I'd founded, unable to keep track of the many meetings, tasks, and personnel of which I was in charge. My longtime girlfriend had left me, prompting me to come to terms with my sexuality and come out to myself and my friends. And fundamentally, something about me had shifted—I had been skeptical, uptight, nervous. But now I was performing poetry at slams, dancing at bonfires in the desert, and traveling to new countries on a whim. At the time, it felt like a rebirth. ©2005 Washingtonpost.Newsweek Interactive Co.

Keyword: Learning & Memory; Depression
Link ID: 8006 - Posted: 06.24.2010

Do you always get what you ask for? A new study finds that when you don't, you might not even notice the difference. Swedish researchers showed a pair of female faces to 120 volunteers for 2 seconds and then asked them to choose which one they thought was more attractive. The researchers then asked the volunteers to explain their choice. The trial was repeated 15 times for each volunteer, using different pairs of faces, but in three of the trials the faces were secretly switched after a decision had been made. Surprisingly, not only were a large number of the volunteers oblivious to the switch when ultimately allowed to take a longer look at their choice, they were actually able to gave detailed explanations for why they preferred the face that, indeed, they had actually rejected. It would be like asking for an apple and then explaining exactly why you wanted the banana you got instead. The researchers call the phenomenon "choice blindness." "She's radiant," gushed one male volunteer about a face he didn't choose. "I would rather have approached her at a bar than the other one. I like earrings!" Another female volunteer said that the face she chose (which in fact she hadn't) looked nicer than the other. © 2005 MSNBC.com

Keyword: Vision; Sexual Behavior
Link ID: 8005 - Posted: 06.24.2010

CINCINNATI--Scientists have found that the site in the brain that controls language in right-handed people shifts with aging--a discovery that might offer hope in the treatment of speech problems resulting from traumatic brain injury or stroke. The shift was documented by researchers led by Jerzy Szaflarski, MD, PhD, assistant professor in the Department of Neurology at the University of Cincinnati (UC) Academic Health Center, and Scott Holland, PhD, professor in the UC departments of biomedical engineering, pediatrics and radiology. Dr. Holland also heads the Pediatric Brain Imaging Research Program at Cincinnati Children's Hospital Medical Center. Their results will be published in the February 2006 edition of the journal Human Brain Mapping. While the site of language activity in right-handed people is originally the left side of the brain, the researchers report, starting as early as age 5 language gradually becomes a function shared by both sides. Between the ages of about 25 to 67, the site becomes more evenly distributed, until language activity can be measured in both hemispheres simultaneously. This, the researchers say, may explain why young children who have had a large portion of one side of the brain surgically removed often recover completely.

Keyword: Language; Stroke
Link ID: 8004 - Posted: 10.07.2005

When evaluating facial attractiveness, participants may fail to notice a radical change to the outcome of their choice, according to a study by researchers at Lund University, Sweden, and New York University. Equally surprising, the study shows that participants may produce confabulatory reports when asked to describe the reasons behind their choices. The findings appear in the October 7 issue of Science. Researchers showed picture-pairs of female faces to the participants and asked them to choose which face in each pair they found most attractive. In addition, immediately after their choice, they were asked to verbally describe the reasons for choosing the way they did. Unknown to the participants, on certain trials, a card magic trick was used to secretly exchange one face for the other. Thus, on these trials, the outcome of the choice became the opposite of what they intended. The researchers measured whether the participants noticed that something went wrong with their choice, both concurrently, during the experimental task, and retrospectively through a post-experimental interview. Less than 10% of all manipulations were detected immediately by the participants, and counting all forms of detection no more than a fifth of all manipulated trials were exposed. The researchers call this effect choice blindness.

Keyword: Sexual Behavior; Vision
Link ID: 8003 - Posted: 10.07.2005

The central nervous system in adult mammals is notoriously bad at healing itself. Once severed, the axons that connect one neuron to another can't regrow. That's why people regain little, if any, movement or sensation after a spinal cord injury. Now, researchers have made a promising discovery. In the 7 October Science, they identify a class of drugs--including one already on the market for treating cancer--that promote axon regeneration in rodents. In the new study, Zhigang He, and Vuk Koprivica at Children's Hospital in Boston along with colleagues tested about 400 small molecules on cultured rodent neurons, hoping to identify ones that promoted the growth of new axonlike extensions. Most of the compounds did nothing, but several compounds that blocked a cell surface protein called the epidermal growth factor receptor (EGFR) had impressive effects. To test the compounds on nerve injuries in live animals, the researchers crushed an optic nerve in adult mice then packed the nerve with foam soaked with one of the EGFR blockers. Two weeks after the injury, the treated mice showed a ninefold increase in axon regeneration compared to untreated animals. Additional work by He's team suggests that the compounds block two kinds of molecular signals: inhibitory molecules embedded in the myelin insulation on axons and inhibitory signals spewed out by support cells that form a scar around the site of injury. "It's a really unexpected finding," says Marie Filbin, a neurobiologist at Hunter College in New York City. She and other experts say they never suspected that EGFR might have a role in thwarting regeneration. The study "identifies a novel target for therapeutic interventions," Filbin says. © 2005 by the American Association for the Advancement of Science.

Keyword: Regeneration; Trophic Factors
Link ID: 8002 - Posted: 06.24.2010

Researchers have discovered a new form of synaptic plasticity, the changes to nerve cells in the brain that underlie learning and memory. The phenomenon, the scientists say, may help govern how a single neuron integrates and processes multiple stimuli. The researchers, led by HHMI investigators Lily Jan and Yuh Nung Jan at the University of California San Francisco, published their findings in the October 7, 2005, issue of the journal Cell. Coauthors on the paper include the Jans' colleagues at UCSF and Robert B. Darnell, an HHMI investigator at The Rockefeller University. Scientists have long known that long-term potentiation (LTP) can strengthen the connections between neurons, so that a nerve cell more readily responds to a signal from its neighbor. This heightened sensitivity can persist for several hours. LTP is best studied in excitatory synapses, where a neurotransmitter molecule is released by one cell and tends to triggers an electrical impulse in the receiving cell. Lily Jan compares the phenomenon to Pavlov's famous experiment in which ringing a bell while feeding a dog causes the dog to associate the two stimuli. LTP, she says, “reminds you of that. If you have two different excitatory inputs and they happen at the same time, it can cause a very long-lasting change.” © 2005 Howard Hughes Medical Institute.

Keyword: Learning & Memory
Link ID: 8001 - Posted: 06.24.2010

Known as "the cocktail party problem," the ability of the brain's auditory processing centers to sort a babble of different sounds, like cocktail party chatter, into identifiable individual voices has long been a mystery. Now, researchers analyzing how both humans and monkeys perceive sequences of tones have created a model that can predict the central features of this process, offering a new approach to studying its mechanisms. The research team--Christophe Micheyl, Biao Tian, Robert Carlyon, and Josef Rauschecker--published their findings in the October 6, 2005, issue of Neuron. For both the humans and the monkeys, the researchers used an experimental method in which they played repetitive triplet sequences of tones of two alternating frequencies. Researchers know that when the frequencies are close together and alternate slowly, the listener perceives a single stream that sounds like a galloping horse. However when the tones are at widely separated frequencies or played in rapid succession, the listener perceives two separate streams of beeps. Importantly, at intermediate frequency separations or speeds, after a few seconds the listeners' perceptions can shift from the single galloping sounds to the two streams of beeps. The researchers could use this phenomenon to explore the neurobiology of perception of auditory streams, because they could explore how perception altered with the same stimulus.

Keyword: Hearing
Link ID: 8000 - Posted: 10.06.2005

Roxanne Khamsi It may not be considered manly for humans to cry. But when male mice shed a tear, they seem to be trying to prove their masculinity. So say Japanese researchers who have discovered that male mice release pheromones in the fluid that moistens their eyes. "Nobody expected that sex-specific pheromones would exist in tears," says Kazushige Touhara of the University of Tokyo in Chiba. Pheromones, the chemicals that convey messages about everything from fear to sexual desire, are most common in sweat in humans, and in urine in mice. It is not clear whether mice ever cry for the same reasons as humans; in this study, their tears were just the result of a basic physiological response that keeps a mouse's eyes wet and comfortable. Touhara says the pheromones in these secretions are probably picked up by females when they groom the faces of their fellow mice. These sexy cues may help females to work out which of their companions are male and therefore potential mates, Touhara and his team report in Nature1. In most vertebrates, pheromones seem to trigger nerve cells in the vomeronasal organs, which are situated in the hard palate between the nose and mouth. Some studies have found evidence for such an organ in the developing human fetus, but the presence of a functioning one in human adults remains controversial. ©2005 Nature Publishing Group

Keyword: Sexual Behavior; Chemical Senses (Smell & Taste)
Link ID: 7999 - Posted: 06.24.2010

When you jaywalk, your ability to keep track of that oncoming truck despite your constantly changing position can be a lifesaver. But scientists do not understand how such constant updating of depth and distance takes place, suspecting that the brain receives information not just from the eye but also from the motion-detecting vestibular system in the middle ear. In studies with monkeys reported in the October 6, 2005, issue of Neuron, Nuo Li and Dora Angelaki of Washington University School of Medicine in St. Louis have demonstrated how such depth motion is updated and strongly implicated the vestibular system in that process. In their experiments, the researchers trained the monkeys to perform memory-guided eye movements. The animals were first shown a light a fixed distance away from their head. Then the researchers flashed one of eight other, closer "world-fixed" target lights. Next, with the room lights turned off, the monkeys were moved either forward or backward and the fixed-distance light flashed, signaling the monkeys that they should look at where they remembered the world-fixed light had flashed. Finally, the room lights and target light were turned on, so the monkey could make any corrective eye movement to the re-lit target. For comparison, the researchers also conducted experiments in which the monkeys were not moved.

Keyword: Miscellaneous
Link ID: 7998 - Posted: 10.06.2005

New studies in mice have shown that immature stem cells that proliferate to form brain tissues can function for at least a year — most of the life span of a mouse — and give rise to multiple types of neural cells, not just neurons. The discovery may bode well for the use of these neural stem cells to regenerate brain tissue lost to injury or disease. Alexandra L. Joyner, a Howard Hughes Medical Institute investigator at New York University School of Medicine, and her former postdoctoral fellow, Sohyun Ahn, who is now at the National Institute of Child Health and Human Development, published their findings in the October 6, 2005, issue of the journal Nature. They said the technique they used to trace the fate of stem cells could also be used to understand the roles of stem cells in tissue repair and cancer progression. Joyner said that previous studies by her lab and others had shown that a regulatory protein called Sonic hedgehog (Shh) orchestrates the activity of an array of genes during development of the brain. Scientists also knew that Shh played a role in promoting the proliferation of neural stem cells. However, Joyner said the precise role of Shh in regulating stem cell self-renewal — the process whereby stem cells divide and maintain an immature state that enables them to continue to generate new cells — was unknown. In the studies published in Nature, Joyner and Ahn developed genetic techniques that enabled them to label neural stem cells in adult mice that are responding to Shh signaling at any time point so they could study which stem cells respond to Shh. © 2005 Howard Hughes Medical Institute.

Keyword: Stem Cells
Link ID: 7997 - Posted: 06.24.2010

By DONALD G. McNEIL Jr. The Food and Drug Administration proposed new rules yesterday to prevent the spread of mad cow disease by banning brains and spinal cords from older cows in all animal feed. "This reduces a very, very low risk to even lower," said Dr. Stephen F. Sundlof, the agency's director of veterinary medicine, in announcing the changes. But the rules are not as strict as those the agency proposed last year and never adopted, and critics promptly denounced them as inadequate. The new proposal still allows chickens, pigs and other noncattle animals to be fed material that some scientists consider potentially infectious, including the brains and spinal cords of young animals, and the eyes, tonsils, intestines and nerves of older ones. Cows can potentially ingest that material because they can be given chicken feed and droppings swept up from the floors of poultry farms, scrapings from restaurant plates, and a calf milk replacement made from cow blood and fat. In the rules proposed in early 2004, poultry litter and plate waste would have been banned. The F.D.A. and the meat industry are "totally committed to continuing the practice of feeding slaughterhouse waste to cows," said John Stauber, the author of "Mad Cow U.S.A." (1997) and a critic of the meat industry who has called for a ban on feeding all animal protein to livestock. Copyright 2005 The New York Times Company

Keyword: Prions
Link ID: 7996 - Posted: 10.05.2005