AUSTIN, Texas--Neurons experience large-scale changes across their dendrites during learning, say neuroscientists at The University of Texas at Austin in a new study that highlights the important role that these cell regions may play in the processes of learning and memory. The research, published online Oct. 23 and in the November issue of the journal Nature Neuroscience, shows that ion channels distributed in the dendritic membrane change during a simulated learning task and that this requires the rapid production of new proteins. "Our new work strongly supports the idea that learning involves changes in dendrites," says Dr. Daniel Johnston, director of the Center for Learning and Memory and professor in the Institute for Neuroscience. The finding could also lead to advances in understanding conditions like epilepsy and age-related memory loss and could point to potential treatment opportunities for such conditions in the future. Dendrites--the thin branch-like extensions of a neuron cell--receive many inputs from other neurons that transmit information through contact points called synapses. Much attention has been focused on the role that changes at synapses play in learning. They change in ways that make it easier for connected neurons to pass information.

Keyword: Learning & Memory
Link ID: 8103 - Posted: 11.03.2005

Symptoms, like difficultly sounding out words, make dyslexia readily detectable. But the causes of the disability are still hard to pinpoint. "Why? What causes these otherwise very bright children to struggle to read?" asks pediatrician Sally Shaywitz, co-director of Yale University's Center for the Study of Learning and Attention, and the author of "Overcoming Dyslexia." "Dyslexia is an unexpected difficulty first in learning to read, and then in having to struggle to read," she explains. "That means the person who is dyslexic has all the factors present that say, 'This person should be a good reader. They're intelligent, they're motivated, and they've had good education. Yet they still struggle to read." If left untreated, childhood dyslexia becomes an adult problem. "It's not something that's outgrown," says neurophysiologist Lynn Flowers from Wake Forest University Baptist Medical Center. "Ten percent of the child and therefore the adult population is affected by dyslexia to some degree," she says. "It isn't an all or nothing kind of disorder, it comes in shades as well." © ScienCentral, 2000-2005.

Keyword: Dyslexia
Link ID: 8102 - Posted: 06.24.2010

As any chef at a greasy spoon can attest, humans have a taste for fatty foods. Now, scientists may know why. Researchers have found a new receptor on mice and rat tongues that detects fat and helps prepare the body to digest it. The results may help explain why some people crave fat more than others and could help researchers uncover new ways to fight obesity. It's long been clear that humans and rodents taste sweet, sour, bitter, salty, and protein-rich foods, but researchers thought we sensed the fat in food by its smell and creamy texture. Over the past decade or so, however, results have dribbled in suggesting we--or at least mice and rats--taste fats. In one study, applying a chemical to the tongue that blocks a fat-digesting enzyme prevented rats and mice from tasting fats and fatty acids, a breakdown product of fats. Intrigued, physiologist Philippe Besnard of the University of Bourgogne in Dijon, France, and colleagues focused on a fatty-acid receptor called CD36 that's found in fat and other tissues. After chemically linking a red fluorescent dye to antibodies that bound CD36, the researchers showed that taste buds glowed red, indicating that CD36 was in the right place to do the job. To see if animals use CD36 to taste fats, the team bred a line of mice that lacked the receptor. When given a choice between their standard fare and fat-enriched treats, normal mice consumed 3 times as much of the junk food, but mutant mice showed no preference, presumably because they couldn't taste the difference. © 2005 by the American Association for the Advancement of Science.

Keyword: Chemical Senses (Smell & Taste)
Link ID: 8101 - Posted: 06.24.2010

By Jennifer Viegas, Discovery News — As women experience their regular menstrual cycle, they undergo bodily changes that can cause emotional mood swings, but scientists have just discovered that women without problems associated with PMS have brains that can regulate the cyclical emotional overloads. The study, published in a recent Proceedings of the National Academy of Sciences, represents the first time that PMS (Premenstrual Syndrome) has been studied using functional MRI brain scanning, along with tests designed to probe emotional changes. The findings suggest that PMS and more serious symptoms associated with menstruation are driven by forces that may be beyond a woman's control. "In the past, many women suffering from PMS were told to, 'Just get over it,' or were asked, 'Why can't you handle this?'" said David Silbersweig, one of the study's authors. Silbersweig, a physician and researcher at Cornell University's Weill Medical College, added, "We now hope that our research will help the public to understand that PMS can involve changes in the brain, and that the condition is not just psychological, but that biological systems are involved that help to control emotions and behavior." © 2005 Discovery Communications Inc.

Keyword: Hormones & Behavior; Emotions
Link ID: 8100 - Posted: 06.24.2010

By Beth Baker Special to The Washington Post In 2001, Ellen Proxmire faced a tough decision regarding her husband -- William Proxmire, the former Democratic senator. Diagnosed seven years earlier with Alzheimer's disease, he frequently wandered from home. He even managed to escape from a locked hospital unit. When he represented Wisconsin from 1957 to 1989, Proxmire had a reputation as a maverick. But the independent streak prized in a politician was dangerous in a person living with Alzheimer's disease. One day he eluded the caregiver hired to keep an eye on him at the Library of Congress, where he still enjoyed a private carrel. Hours later he was found walking on the Southeast Freeway. Someone recognized him and picked him up and brought him home, his wife said. Much as she hated to admit it, Ellen Proxmire knew she could no longer care for her husband at home. She visited some 20 Alzheimer's residential facilities in the Washington area and in Arizona, where she hoped to live. Even those with good reputations she found dismal. "People were drugged and sitting in a corner, tied to chairs," she said. "And there are some places who don't want someone who is difficult." © 2005 The Washington Post Company

Keyword: Alzheimers
Link ID: 8099 - Posted: 06.24.2010

HOUSTON --- Visual information can be processed unconsciously when the area of the brain that records what the eye sees is temporarily shut down, according to research at Rice University in Houston. The research, published the week of Oct. 31 in the Proceedings of the National Academy of Sciences' (PNAS) online Early Edition, suggests the brain has more than one pathway along which visual information can be sent. For the study, the researchers induced temporary, reversible blindness lasting only a fraction of a second in nine volunteers with normal vision. Transcranial magnetic stimulation (TMS), a harmless noninvasive technique using brief magnetic pulses, was applied to the volunteers' visual cortex -- the area at the back of the brain that processes what the eye sees - to interrupt the normal visual pathway. The volunteers looked at a computer screen, and during their momentary blindness, either a horizontal or a vertical line or a red or a green dot flashed on the screen. Researchers then asked the study participants whether they had seen a horizontal or a vertical line; because their primary visual pathway had been shut down, the participants reported that they saw nothing. However, when forced to guess which line had appeared on their computer screen, the participants gave the correct answer 75 percent of the time. When the participants had to guess whether a red or a green dot had flashed on the screen, they gave the correct answer with 81 percent accuracy.

Keyword: Vision
Link ID: 8098 - Posted: 11.01.2005

By Jason Feifer From across the apartment, my girlfriend smelled smoke. "Is something burning?" she called to me in the kitchen. No, everything's fine, I yelled back. A few minutes later, she came in to investigate. She found me washing dishes, oblivious to the smoking George Foreman grill beside me. "You're so dying in a fire," she said as she yanked the plug from the wall. I don't know why I didn't see the smoke, but there was good reason I didn't smell it. Like an estimated 14 million Americans, I suffer from smell loss. Like a smaller number of them, I can't taste, either. I can occasionally appreciate a flower's aroma or food's flavor, but only vaguely and superficially. My imagination helps fill in the blanks; but when I'm blindfolded, I confuse mint ice cream and peanut butter ice cream. My girlfriend, who has the olfactory capabilities of a bloodhound, has run me through this test numerous times. She, like most everyone else I tell about this, simply cannot understand my experience. I have a hard time explaining it myself. It's as if my tongue and nose can sense differences -- water tastes different from juice, say, and unscented air smells different from perfume -- but the differences are faint and forgettable, and I have no ability to identify them. Chocolate is strawberry is scrambled eggs. © 2005 The Washington Post Company

Keyword: Chemical Senses (Smell & Taste)
Link ID: 8097 - Posted: 06.24.2010

By ERIC NAGOURNEY Botox may do more than just get rid of wrinkles. In addition to providing relief from eye spasms and migraines, Botox, formally botulinum toxin A, has now been found useful in treating the intense facial pain called trigeminal neuralgia. In a study published in the Oct. 25 issue of Neurology, the drug provided partial or complete relief to all 13 patients tested. Until now, anticonvulsant drugs or neurosurgery have been the only treatments for the disorder. The drugs can have unpleasant side effects, and the surgery is expensive and carries risks. Neither treatment is universally effective. Dr. Stephen D. Silberstein, a co-author on the paper, said he would recommend Botox even though it had not been randomly tested in controlled clinical trials. "The purists would say you shouldn't do something not proven in a double-blind study," Dr. Silberstein said, referring to research in which one group is given the medicine and another group is given a placebo. "But the surgical alternatives are unproven procedures that are more expensive and more risky. I don't see any reason not to use it just because we don't have all the evidence in." The Botox treatment requires injections of 10 units four or five times a year. Botox costs about $5 a unit, according to Dr. Silberstein, who is a professor of neurology at Jefferson Medical College in Philadelphia. Copyright 2005 The New York Times Company

Keyword: Pain & Touch
Link ID: 8096 - Posted: 11.01.2005

Looking in a mirror at a reflection of their healthy hand could help people with persistent pain ease their symptoms and eventually overcome their problem, say scientists in the latest edition of the journal Clinical Medicine. The treatment, being developed by researchers from the University of Bath and the Royal National Hospital for Rheumatic Diseases (RNHRD), is based on a new theory about how people experience pain even when doctors can find no direct cause. This ‘cortical’ model of pain suggests that the brain’s image of the body can become faulty, resulting in a mismatch between the brain’s movement control systems and its sensory systems, causing a person to experience pain when they move a particular hand, foot or limb. Researchers believe that this kind of problem could be behind a host of pain-related disorders, such as complex regional pain syndrome and repetitive strain injury. In an investigation of whether this system can be corrected using mirrors to trick the brain, researchers asked a number of patients with complex regional pain syndrome (a chronic debilitating condition affecting 10,000 – 20,000 patients in the UK at any one time) to carry out routine exercises in front of a mirror. University of Bath © 2004

Keyword: Pain & Touch
Link ID: 8095 - Posted: 06.24.2010

Genetic variations that cause miscues in brain development may play an important role in dyslexia, according to new research presented last week at a meeting of the American Society of Human Genetics in Salt Lake City. People with dyslexia have reading impairments despite normal intelligence. The problem affects between 5% and 17% of the population. In the last few years, geneticists have begun to point the finger at particular genes (ScienceNOW, 22 February). However, little is known about how these genes might contribute to the condition. In one new study, a collaboration of 20 researchers led by Haiying Meng and Jeffrey Gruen of Yale University School of Medicine homed in on a region of chromosome 6 that has been implicated in previous dyslexia studies. Using DNA collected from 536 people with a dyslexic in their families, the researchers tracked 147 single-nucleotide polymorphisms (SNPs), places where the genetic code differs by one letter in different people. Searching for SNPs that tend to have one "spelling" in people with reading impairments and another spelling in normal readers, the researchers found that a disproportionate number of such SNPs showed up in a gene called DCDC2. © 2005 by the American Association for the Advancement of Science.

Keyword: Dyslexia; Genes & Behavior
Link ID: 8094 - Posted: 06.24.2010

Liars could be caught out by the reaction of their stomachs to telling untruths, suggests preliminary research from the University of Texas, US. The team believe that the early-stage technique could one day improve the accuracy of polygraph tests, which rely mostly on monitoring heart activity. “The heart is unreliable because it’s affected by not only by your brain, but by many other factors, such as hormones,” says Pankaj Pasricha, who is leading the team. “The gut has a mind of its own – literally. It has its own well-developed nervous system that acts independently of almost everything except your unconscious brain.” The test uses a device called an electrogastrogram (EGG) to determine when a person’s stomach “beats” speed up from the typical three per minute. Whereas heart beats can increase whether a person is lying or telling the truth, the group’s initial findings from 16 test subjects reveal that the stomach’s rate typically does not increase if a person is telling the truth, however nervous they may be. “This might very well be the case,” says Kevin Murphy, a psychologist at Penn State University, Pennsylvania, US, who recently headed a panel for the US National Academy of Sciences to analyse the science behind polygraph devices. “But polygraph detectors, whatever their ilk, measure stress and not lying. This new test might give more, potentially very useful, data. But it won’t give you the definitive truth.” © Copyright Reed Business Information Ltd.

Keyword: Stress
Link ID: 8093 - Posted: 06.24.2010

Roxanne Khamsi Mickey Mouse may have kept quiet during his early days on the silver screen, but his lab counterparts seem to have a penchant for song. That's the finding in an analysis of the ultrasonic sounds made by male mice wooing potential mates. For years, animal-behaviour experts have known that mice make vocalizations that are too high in pitch to be picked up by the human ear. Young mice, for example, make 'isolation calls' when cold or distressed. And male mice emit ultrasonic sounds in the presence of a potential mate or in response to chemical sex cues, called pheromones, in the urine of female mice. But until now, scientists had not examined these sounds for musical patterns. Thanks in part to a sophisticated computer program, Timothy Holy and Zhongsheng Guo of the Washington University School of Medicine in St Louis, Missouri, were able to tackle this challenge. Holy began by writing software that shifts the pitch of the male mouse's sounds, making the sounds deeper so that they can be heard by humans. "No one had ever pitch-shifted the mouse vocalization," he says. "The first time I played it back it was pretty surprising: it sounded so much like birdsong." ©2005 Nature Publishing Group

Keyword: Sexual Behavior; Language
Link ID: 8092 - Posted: 06.24.2010

Vulnerability to anxiety may be down to the size of a brain structure involved in fearful memories, say US scientists. People with a thicker ventromedial prefrontal cortex were better able to cope with stressful experiences. The findings may help explain why some people develop post-traumatic stress disorder (PTSD) while others bounce back after adversity, say the authors. The Massachusetts General Hospital study appears in Proceedings of the National Academy of Science. While it is normal to experience physical and psychological symptoms after an extremely stressful event, such as the recent London terrorist attacks, some people will continue to be consumed by overwhelming fear and may develop PTSD. A person with PTSD may experience unwanted flashbacks, poor sleep and depression, and avoidance certain situations that could trigger memories of the event. Studies in animals suggest that the ventromedial prefrontal cortex (vmPFC) is involved with helping the brain forget fearful events. Also, studies of have shown that people with PTSD have unusually inactive vmPFCs, again suggesting that this brain region is important in anxiety. In the current study, Dr Mohammed Milad and colleagues scanned the brains of 14 volunteers. (C)BBC

Keyword: Stress
Link ID: 8091 - Posted: 10.31.2005

By Shankar Vedantam, Washington Post Staff Writer For centuries, poets, philosophers and scientists have debated why humans spend as much as a third of their lives asleep. For Shakespeare, sleep was the "balm of hurt minds" -- denied to murderers such as Macbeth. For Sigmund Freud, sleep provided a platform for dreams, an outlet for the psyche to work out complex and dangerous feelings. Scientists today believe sleep consolidates learning and memory, and supports many essential mental and physical functions. The theorists have long disagreed about one another's ideas, but most agree on one thing: If nature makes people sleep away so much of their lives, the reason has to be something crucial. That seemed to be the only way to explain why sleep-deprived people crave sleep so badly that they doze off behind the wheel of a car going 60 mph, and why rats deprived of sleep die sooner than rats deprived of food. Yet a wealth of sleep research has regularly produced baffling paradoxes and conflicting lines of evidence about the uses, role and need for sleep. If sleep is primarily about providing mental rest, why do people's brains remain so active during sleep, as research in recent decades has found? © Copyright 1996-2005 The Washington Post Company

Keyword: Sleep; Evolution
Link ID: 8090 - Posted: 06.24.2010

By PAUL COLLINS The moment I opened my eyes I knew something was wrong. The sun wasn't up yet, and a cry was forming in Morgan's throat. I padded over to his bed, puzzled. His darkened room was filled with battered brass instruments, playing cards, thick reference books - the inscrutable fascinations of an autistic 5-year-old. Morgan had always been in his own world, but it was a fairly happy one. In his waking hours he'd hum "In the Hall of the Mountain King" while shuffling through mysterious sequences of pinochle cards; lately he had become engrossed in an illustrated encyclopedia of electric guitars, squinting and smiling at the old pictures and names: Danelectro, Rickenbacker, Gretsch. Sometimes he'd brush past his baby brother and march up to me with a lump of Play-Doh. "Gibson ES-350," he'd demand. As I'd gamely fashion a fretboard and tuners out of clay, he'd grab his tarnished French horn, skip outside to the tree swing and blast out wobbling notes at the neighbors: borp, brap, boorp. I leaned farther over his bed. "Morgan?" Bam. I staggered back, smacking away another punch, yelling in surprise, "Go to your room!" - which didn't mean much since he was already in it. I retreated across the hall and snapped on the bathroom light. Blood was flowing from my nose. Behind me Morgan thrashed on his bed, pounding and kicking the bedroom wall, screaming. Copyright 2005 The New York Times Company

Keyword: Autism; Depression
Link ID: 8089 - Posted: 10.31.2005

By RANDY KENNEDY SITTING the other day in front of Picasso's rapturous "Girl Before a Mirror" at the Museum of Modern Art, Rueben Rosen wore the dyspeptic look of a man with little love for modern art. But the reason he gave for disliking the painting was not one you might expect to hear from an 88-year-old former real estate broker. Xanthe Alban-Davies discusses Picasso's "Girl Before a Mirror" with, from left, Rueben Rosen, Irene Brenton and Sheila Barnes at the Museum of Modern Art. "It's like he's trying to tell a story using words that don't exist," Mr. Rosen said. "It's like he's trying to tell a story using words that don't exist," Mr. Rosen said finally of Picasso, fixing the painter's work with a critic's stare. "He knows what he means, but we don't." This chasm of understanding is one that Mr. Rosen himself stares into every day. He has midstage Alzheimer's disease, as did the rest of the men and women who were sitting alongside him in a small semicircle at the museum, all of them staring up at the Picasso. It was a Tuesday, and the museum was closed, but if it had been open other visitors could have easily mistaken the group for any guided tour. Mr. Rosen and his friends did not wear the anxious, confused looks they had worn when they first arrived at the museum. They did not quarrel in the way that those suffering from Alzheimer's sometimes do. And when they talked about the paintings, they did not repeat themselves or lose the thread of the discussion, as they often do at the long-term care home where most of them live in Palisades, N.Y. Copyright 2005 The New York Times Company

Keyword: Alzheimers
Link ID: 8088 - Posted: 10.31.2005

Your brain is a time machine with three modes that control everything from instantaneous tasks such as moving, to maintaining long trains of thought and ultimately staying in synch with night and day. That's what scientists say. But they have no clue how most of it works. Focusing on the poorly understood middle time zone, where the brain does some of its best work, researchers at Duke University summarize this latest thinking in a new article in the journal Nature Reviews Neuroscience. Scientists have long understood human and animal brains to be governed in part by a circadian clock, which keeps us in synch with night and day. The rhythm of this 24-hour clock encourages nighttime sleep and allows many people to awaken with no help from a rooster. Another clock is thought to operate at the millisecond level, controlling movement and speech, among other vital functions that occur so quickly we don't really think about them. But in between, there must be a third timekeeper of the mind to aid all the functions that require seconds to minutes of attention. Nobody is sure about this, though. © 2005 Microsoft

Keyword: Miscellaneous; Biological Rhythms
Link ID: 8087 - Posted: 06.24.2010

By SANDRA BLAKESLEE One year after scientists discovered a gene whose flaw contributes to dyslexia, two more such genes have now been identified. The findings, described yesterday in Salt Lake City at a meeting of the American Society of Human Genetics, support the idea that many people deemed simply lazy or stupid because of their severe reading problems may instead have a genetic disorder that interfered with the wiring of their brains before birth. "I am ecstatic about this research," said Dr. Albert M. Galaburda of Harvard Medical School, a leading authority on developmental disorders who was not involved in the latest discoveries. The findings, added to last year's, mean that for the first time, "we have a link between genes, brain development and a complex behavioral syndrome," Dr. Galaburda said. As many as a dozen genes are probably involved in the disorder, he said, with each playing a role in the necessary migration of neurons as the brain's circuitry develops. Researchers said a genetic test for dyslexia should be available within a year or less. Children in families that have a history of the disorder could then be tested, with a cheek swab, before they are exposed to reading instruction. If children carry a genetic risk, they could be placed in early intervention programs. Copyright 2005 The New York Times Company

Keyword: Dyslexia; Genes & Behavior
Link ID: 8086 - Posted: 10.29.2005

By Robert Sanders BERKELEY – Picky female frogs in a tiny rainforest outpost of Australia have driven the evolution of a new species in 8,000 years or less, according to scientists from the University of Queensland, the University of California, Berkeley, and the Queensland Parks and Wildlife Service. "That's lightning-fast," said co-author Craig Moritz, professor of integrative biology at UC Berkeley and director of the Museum of Vertebrate Zoology. "To find a recently evolved species like this is exceptional, at least in my experience." When isolated populations of the green-eyed tree frog (gray and brown) met again 8,000 years ago, they found that each had changed in subtle ways. The calls of the male frogs were different, and more importantly, hybrid offspring were less viable. One population that was cut off from its southern kin (pink) found a way to ensure healthy young. Females, who choose mates based only on their call, began selecting mates with a the southern call type. Over thousands of years, this behavior exaggerated the pre-existing differences in call, lead to smaller body size in males of the "isolated southern population" and resulted in rapid speciation between the two populations of the southern lineage. The yet-to-be- named species arose after two isolated populations of the green-eyed tree frog reestablished contact less than 8,000 years ago and found that their hybrid offspring were less viable. To avoid hybridizing with the wrong frogs and ensure healthy offspring, one group of females preferentially chose mates from their own lineage. Over several thousand years, this behavior created a reproductively isolated population - essentially a new species - that is unable to mate with either of the original frog populations. Copyright UC Regents

Keyword: Sexual Behavior; Evolution
Link ID: 8085 - Posted: 06.24.2010

Researchers trying to crack one of medicine’s most perplexing unsolved mysteries can now keep abreast of late-breaking developments via the Schizophrenia Research Forum, a website launched this month with funding from the National Institutes of Health’s (NIH) National Institute of Mental Health (NIMH). Sponsored by NARSAD, The Mental Health Research Association, the site bills itself as a “virtual community” where researchers can link-up with colleagues and potential collaborators, learn about new findings, meetings and funding opportunities, and critique each other’s articles and ideas. “We’re hoping that the Forum will become a catalyst for creative thinking that will speed the pace of discovery,” said NIMH Director Thomas Insel, M.D. The site (www.schizophreniaforum.org) includes original news stories and interviews with leading scientists in the field. Among specific forums that invite contributions from the field, “Current Hypotheses” presents theory reviews, while an “Idea Lab” posts less formal treatments. Most features of the site are interactive and solicit comment. There will also be live chats with experts that will be archived for later viewing. For example, NIMH senior advisor Mayada Akil, M.D., who represents the Institute to the Forum, is tentatively scheduled to co-lead a discussion with Dr. Irving Gottesman, University of Virginia, on “Identifying Quantifiable Phenotypes in Schizophrenia Research.”

Keyword: Schizophrenia
Link ID: 8084 - Posted: 06.24.2010