By Katherine Unger Some memories are best forgotten. But there's no such luxury for a woman known as 'AJ,' who remembers the details--what she did, who she was with--for every day of the past 30 years. Neuroscientists have coined the term "hyperthymestic syndrome" to describe this first-documented case of memory dominating a person's life. Nearly 6 years ago, neuroscientist James McGaugh of the University of California, Irvine, received an e-mail from then 34-year-old AJ asking for help. "[S]ince I was eleven I have had this unbelievable ability to recall my past," she wrote. She described her life as consumed by the "burden" of memories that were "non-stop, uncontrollable and totally exhausting." McGaugh and his colleagues arranged several meetings with AJ, where they asked her, without prior warning, to recall particular dates. One such "pop quiz" asked her to write down the dates of the previous 24 Easters. In 10 minutes, she produced a list of dates, along with what she had done that day. All the dates were correct, except for one that was off by 2 days. Two years later, the researchers sprung the same test on her, and she gave the exact same responses, but this time, all the dates were right. "She sort of has a vacuum cleaner sucking up all of the personal experiences and storing them away so that they're available" for recall, says McGaugh. © 2006 American Association for the Advancement of Science

Keyword: Learning & Memory
Link ID: 8650 - Posted: 06.24.2010

Whether depressed patients will respond to an antidepressant depends, in part, on which version of a gene they inherit, a study led by scientists at the National Institutes of Health (NIH) has discovered. Having two copies of one version of a gene that codes for a component of the brain’s mood-regulating system increased the odds of a favorable response to an antidepressant by up to 18 percent, compared to having two copies of the other, more common version. Since the less common version was over 6 times more prevalent in white than in black patients — and fewer blacks responded — the researchers suggest that the gene may help to explain racial differences in the outcome of antidepressant treatment. The findings also add to evidence that the component, a receptor for the chemical messenger serotonin, plays a pivotal role in the mechanism of antidepressant action. The study, authored by National Institute of Mental Health (NIMH) researchers Francis J. McMahon, M.D., Silvia Buervenich, Ph.D., and Husseini Manji, M.D., along with collaborators at several other institutions, was posted online March 8 and will appear in the May, 2006 American Journal of Human Genetics. “This discovery brings us closer to the day when clinicians will be able to offer treatment options and medications that are tailored and personalized to be optimally effective for individual patients,” said NIH Director Elias A. Zerhouni, M.D.

Keyword: Depression; Genes & Behavior
Link ID: 8649 - Posted: 06.24.2010

A swaying tree and a moving person activate distinctive areas of the brain's visual cortex, since recognizing people is essential for social interaction. So, an important question in exploring the visual system is how the visual cortex manages such specific recognition of "biological motion." In an article in the March 16, 2006, issue of Neuron, Marius Peelen and colleagues at the University of Wales, Bangor have used detailed functional magnetic resonance (fMRI) imaging of human volunteers to shed new light on this process. The widely used analytical technique of fMRI employs harmless magnetic fields and radio waves to measure blood flow in brain regions, which reflects brain activity in their region. In their experiments, the researchers found that in detecting biological motion the visual cortex not only uses a specific region known to detect motion of other people, but engages areas that respond to the static human form as well. The researchers designed their experiments to give subjects information only on biological motion and not on a human form. Specifically, they scanned the subjects' brains while showing them only "point-light" animation of human movement such as jumping or throwing. These animations consist only of a small number of white dots on a black background, not portraying skin, clothes, or other specific features of a human in action.

Keyword: Vision
Link ID: 8648 - Posted: 03.16.2006

Jacqueline Ruttimann The concave-eared torrent frog could give opera divas a run for their money. Reaching a pitch in the ultrasonic range, these frogs perform arias to be heard over the rushing waters of their habitat, the Huangshan Hot Springs in China. Ultrasonic communication uses sound at a frequency greater than the upper limits of human hearing, around 20 kilohertz, and is thought to exist only in certain mammals, such as bats, whales and some rodents. Now it seems that some frogs have evolved the ability to hit the high notes. Researchers have now measured the torrent frogs (Amolops tormotus) warbling at up to 34 kilohertz. "This is somewhat amazing," says Albert Feng, an acoustic specialist at the Beckman Institute at the University of Illinois, Urbana, and lead author of a paper in the latest issue of Nature1. Feng had previously noted the frogs' ability to sing in the ultrasonic range (see 'Frog sings like a bird'). But it wasn't clear until now that the frogs were actually using this to communicate, rather than it being a side-effect of more audible croaking. Many frogs have evolved visual signals to complement their croaks and make them more noticeable to mates, says herpetologist Michael Ryan of the University of Texas, Austin. The torrent frog, he says, seems to have taken a different tactic in its noisy environment. ©2006 Nature Publishing Group

Keyword: Hearing; Animal Communication
Link ID: 8647 - Posted: 06.24.2010

Helen Pearson A US team has identified what could be the earliest indication of Alzheimer's, a discovery that may help to diagnose the disease and perhaps stop it progressing. Researchers believe that some people show signs of memory loss years before they develop Alzheimer's. But they are not sure what causes these problems, or how they turn into full-blown dementia. To find out, Karen Ashe at the University of Minnesota, Minneapolis, and her team studied a strain of mice that, like people, develop mild memory problems in middle age before getting more severe Alzheimer's symptoms. The mice were genetically engineered to make a version of a human protein called amyloid-. Researchers know that this protein clogs the brains of Alzheimer's patients late in the disease. By extracting amyloid- from the animals' brains, the team discovered a knot of 12 proteins that appears outside brain cells just as memory loss occurs. These clusters, which it calls A*56, are different from the large plaques of amyloid- that form later in Alzheimer's patients. ©2006 Nature Publishing Group

Keyword: Alzheimers; Learning & Memory
Link ID: 8646 - Posted: 06.24.2010

Roxanne Khamsi Elderly patients taking certain drugs to lower their blood pressure appear to have a markedly reduced risk of Alzheimer’s disease, researchers report. Results from their short-term study suggest that some of these medications could slash this risk by up to 70%. Previous research has shown that high blood pressure, also known as hypertension, can increase a person’s chances of developing Alzheimer’s disease. Doctors commonly prescribe patients medications such as diuretics, which cause the kidneys to excrete water and salt, to lower blood pressure. Beta-blockers, which slow the heart rate and widen blood vessels, also work against hypertension. Doctors suspected that diuretics and beta-blockers could reduce the risk of dementia such as Alzheimer’s disease because these drugs improve blood-vessel function, perhaps helping the brain to receive better support. But studies exploring this possibility offered conflicting evidence. For this reason, Peter Zandi of the Johns Hopkins Bloomberg School of Public Health in Maryland, US, and his colleagues recruited elderly participants for their study in the mid 1990s and asked them about their use of medications such as beta-blockers and diuretics. Roughly half of the subjects in the study used antihypertensive drugs. And those taking these medicines typically used them for at least a couple of years. © Copyright Reed Business Information Ltd.

Keyword: Alzheimers
Link ID: 8645 - Posted: 06.24.2010

Researchers at the University of Minnesota Medical School and the Minneapolis VA Medical Center have for the first time identified a substance in the brain that is proven to cause memory loss. This discovery in mice gives drug developers a target for creating drugs to treat memory loss in people with dementia. The research, led by Professor of Neurology Karen H. Ashe, M.D., Ph.D., will be published in the March 16, 2006, issue of Nature. "Finding the specific cause of memory loss and cognitive decline gives scientists a protein complex to target," Ashe said. "Now we can begin to work on how that protein leads to the disease and what we can do to prevent it from harming the brain." Once the memory-robbing protein complex is better understood, drugs could be developed to stop Alzheimer's disease in its tracks. Currently about 4.5 million Americans live with Alzheimer's disease, a number that is projected to increase to 14 million in the next 20 years. In the past, it was generally accepted that Alzheimer's disease was caused by plaques and tangles, unnatural accumulations of two naturally occurring proteins in the brain: amyloid-beta, which builds into plaques between nerve cells in the brain; and tau, which forms the tangles bundles inside nerve cells. Ashe's lab proved last year that the tangles are not the cause of memory loss; this latest research shows the plaques aren't a major cause either.

Keyword: Alzheimers; Learning & Memory
Link ID: 8644 - Posted: 03.16.2006

Spinach may not give you popeye's super strengt, but digging into that spinach salad could help to protect you against the leading cause of blindness worldwide — cataracts — as well as helping your wasteline. "I've always been interested in the role of diet in disease," says nutrition researcher Joshua Bomser. He had a particular interest in the plant pigments that play a critical role in photosynthesis, known as carotenoids, that are found in many of the everyday fruits and vegetables we eat. "There's been some speculation that they can prevent the development of skin cancer, as well as the development of macular degeneration and age-related cataracts," he explains. "There are about 40 carotenoids that naturally occur in the diet. Of those, only lutein and zeaxanthin accumulate in the lens of the eye." Lutein and zeaxanthin are found in vegetables like kale, spinach and collard greens. So, Bomser and his colleagues at Ohio State University wanted to find out whether these plant pigments, which are found in high concentrations in dark green leafy vegetables, could protect the lens of the eye against the damaging ultraviolet rays of the sun and prevent cataracts. "We were able to show that lutein and zeaxanthin could reduce ultraviolet radiation induced damage in the lens," Bomser says. © ScienCentral, 2000-2006.

Keyword: Vision
Link ID: 8643 - Posted: 06.24.2010

It's hard not to look when you pass an accident on the road, but doing so can be dangerous. Vanderbilt University psychologist David Zald says "emotional" images — like car accidents, a gruesome murder scene, or a bit of pornography — can briefly blind us to everything else around us, limiting our senses and potentially putting us at risk. "Something that's emotional not only captures our attention, but it does it to such an extent that it's blocking information that comes in after. We're no longer even looking at that image," says Zald. As reported in Psychonomic Bulletin and Review, Zald and his colleagues trained twenty-one people to spot a neutral target image out of a series flying by at ten pictures per second, and then state whether it was rotated to the left or the right. The volunteers performed well except when either a gory or erotic image — more graphic than can be shown here — appeared before the target image. Co-author Steven Most, from Yale University, says in those cases participants were far more likely to miss the target. Zald says these emotional blindings happen all the time in our daily lives, but are probably most important for drivers, since a lapse in attention of less than a second is enough to cause an accident. © ScienCentral, 2000-2006.

Keyword: Attention; Vision
Link ID: 8642 - Posted: 06.24.2010

By John Bohannon Get a whiff of clove just as you sniff a rose, and the mix smells like carnation. How does our brain create such novel scents seemingly out of thin air? A new study of how the mouse brain responds to a variety of odors may offer an answer. An enduring mystery of smell is how humans can describe far more odors than they have nose receptors to detect. Smells begin when receptors--there are 347 different ones in humans--in the nose latch onto molecules in the air. The receptor then transmits a signal to the brain, which tells us what we're sniffing. Ostensibly, we should be able to distinguish the different scents that make them up, but this isn't always the case. One theory is that the brain sometimes mixes and matches signals that come from the nose to encode unique combo-scents. To test the idea, Linda Buck and Zhihua Zou, neuroscientists at the Fred Hutchinson Cancer Research Center in Seattle, Washington, and the University of Texas in Galveston, respectively, gave mice a whiff of chemicals that smell like either clove, chocolate, citrus, fish, vanilla, or apple. Some mice were exposed to individual scents while others sniffed two different ones at once. To see how the mice processed these smell signals, the researchers turned to the brain's smell center, the olfactory cortex. A gene called Arc is known to turn on when the neuron fires--so by tracking its expression in this region of the brain, the team could determine which neurons switched on in response to specific smells. © 2006 American Association for the Advancement of Science

Keyword: Chemical Senses (Smell & Taste)
Link ID: 8641 - Posted: 06.24.2010

By Mary Beckman Bug parents have it easy. Instead of suffering the starving cries of their babies like bird and mammal mommies do, new research indicates that insects merely need a whiff of their kids to gauge what little ones need. The new findings reveal a novel way for offspring to communicate hunger. Most larvae aren't blessed with a strong set of noisemakers. So it's a safe bet that they must get their parents' attention in some other way. Recognizing that bugs tend to use chemical signals to communicate with each other, evolutionary biologist Edmund Brodie III of Indiana University, Bloomington, wondered if baby insects speak by stinking. To find out, Brodie and colleagues looked at parental feeding behavior in burrower bugs (Sehirus cinctus). Adults are about the size of a pencil eraser, and the youngest babes--there can be up to 100 per brood--look like bright red pinheads. The researchers separated the babies into two groups: One got plenty to eat, while the other was underfed. They then collected the volatile chemicals wafting from each clutch. Finally, using a "smell-o-tron," the researchers blew these odors toward mother bugs. © 2006 American Association for the Advancement of Science

Keyword: Chemical Senses (Smell & Taste); Sexual Behavior
Link ID: 8640 - Posted: 06.24.2010

Biologists at New York University have identified a key factor that enables photoreceptor cells to decide their color sensitivity. The findings, which were uncovered by researchers in Professor Claude Desplan's laboratory in NYU's Center for Developmental Genetics, were published in the March 9th issue of the journal Nature. The researchers used the fruit fly Drosophila as a genetic model system to study stochastic events like color sensitivity in photoreceptor cells. The eye of the fly contains some 800 optical units, called ommatidia. Each ommatidium contains six outer and two inner photoreceptors (R7 and R8); the inner receptors detect color, like cone cells in human eyes. Approximately 30 percent of the ommatidia are named "pale," with sensitivity to blue light, and about 70 percent are called "yellow," with sensitivity to green light. This ratio of 30 to 70 appears in a large number of diverse species of flies. However, these receptors are stochastically (or randomly) distributed. Desplan, the corresponding author of the article, said, "The key question we explored was how each individual R7 and R8 receptor 'decides' to be either 'pale' or 'yellow,' and how this 'decision' contributes to the stochastic distribution of each type in the mosaic of color photoreceptors in the fruit flies' eyes."

Keyword: Development of the Brain; Vision
Link ID: 8639 - Posted: 03.10.2006

Will Knight A computer controlled by the power of thought alone has been demonstrated at a major trade fair in Germany. The device could provide a way for paralysed patients to operate computers, or for amputees to operate electronically controlled artificial limbs. But it also has non-medical applications, such as in the computer games and entertainment industries. The Berlin Brain-Computer Interface (BBCI) – dubbed the "mental typewriter" – was created by researchers from the Fraunhofer Institute in Berlin and Charité, the medical school of Berlin Humboldt University in Germany. It was shown off at the CeBit electronics fair in Hanover, Germany. The machine makes it possible to type messages onto a computer screen by mentally controlling the movement of a cursor. A user must wear a cap containing electrodes that measure electrical activity inside the brain, known as an electroencephalogram (EEG) signal, and imagine moving their left or right arm in order to manoeuvre the cursor around. "It's a very strange sensation," says Gabriel Curio at Charité. "And you can understand from the crowds watching that the potential is huge." © Copyright Reed Business Information Ltd.

Keyword: Miscellaneous
Link ID: 8638 - Posted: 06.24.2010

Researchers at the Salk Institute for Biological Studies have identified an important circuit in the spinal cord that controls the speed with which our leg muscles contract and relax. Their findings mark an important milestone in understanding the neural circuitry that coordinates walking movements - one of the main obstacles in developing new treatments for spinal cord injuries. "Knowing which circuits are important and understanding how they control the essential aspects of walking should put us in a better position to design treatments or implants that restore or activate these pathways," said Martyn D. Goulding, Ph.D., a professor in the Molecular Neurobiology Laboratory. The Salk research team – led by Goulding– published their findings in the March 9, 2006 issue of the journal Nature. Joint lead authors were Simon Gosgnach, Ph.D. and Guillermo M. Lanuza, Ph.D. in Goulding's laboratory. Whether fish or fowl, the muscle contractions that allow us to move generally have certain rhythmic properties. It has been known for some time that a central pattern generator (CPG) – specialized groups of neurons in the spinal cord – functions as the control and command center for these rhythmic movements. As such, the CPG lies at the heart of all locomotion. Remarkably, this circuitry functions without any input from the brain, which explains why headless chickens run away from the butcher's block.

Keyword: Miscellaneous
Link ID: 8637 - Posted: 06.24.2010

CAMBRIDGE, Mass.--Researchers at MIT and Harvard Medical School have identified a compound that interferes with the pathogenic effects of Huntington's disease, a discovery that could lead to development of a new treatment for the disease. There is no cure for Huntington's, a neurodegenerative disorder that now afflicts 30,000 Americans, with another 150,000 at risk. The fatal disease, which is genetically inherited, usually strikes in midlife and causes uncontrolled movements, loss of cognitive function and emotional disturbance. "There are now some drugs that can help with the symptoms, but we can't stop the course of the disease or its onset," said Ruth Bodner, lead author on a paper appearing online the week of Mar. 6 in the Proceedings of the National Academy of Sciences (PNAS). Bodner is a postdoctoral fellow in MIT's Center for Cancer Research. The compound developed by Bodner and others in the laboratories of MIT Professor of Biology David Housman, Harvard Medical School Assistant Professor Aleksey Kazantsev and Harvard Medical School Professor Bradley Hyman might lead to a drug that could help stop the deadly sequence of cellular events that Huntington's unleashes. "Depending on its target, any one compound will probably block only a subset of the pathogenic effects," Bodner said.

Keyword: Huntingtons
Link ID: 8636 - Posted: 03.09.2006

By Thomas Oberst Imagine seeing a former high school classmate you always wanted to know better. Then imagine seeing that kid who used to push you in the hallways. Do you react differently? What happens in your brain during these encounters? In fact, different areas of the brain react differently when recognizing others, depending on the emotions attached to the memory, a team of Cornell University research psychologists has found. The team, led by professor of psychology Robert Johnston, has been conducting experiments to study individual recognition. But rather than crash high school reunions with an MRI machine in tow, the researchers stayed in their laboratory and created social encounters between golden hamsters. Then they examined the animals' brains for evidence of those encounters. Last year Johnston's team conducted the first experiment to demonstrate the neural basis of individual recognition in hamsters and identify which areas of the brain play a role. The results were published in the Dec. 7, 2005, issue of the Journal of Neuroscience. Better understanding these mechanisms, Johnston said, may be of central importance in treating certain forms of autism, Asperger syndrome, psychopathy and social anxiety disorders.

Keyword: Sexual Behavior; Chemical Senses (Smell & Taste)
Link ID: 8635 - Posted: 03.09.2006

By Jennifer Viegas, Discovery News — Many reptiles in the wild can survive for days, even when over half of their body water is frozen, and now scientists have identified three groups of genes that help keep these animals from sustaining damage or death during this near-Popsicle condition. The discovery not only helps to solve the reptile freezing mystery, but scientists also hope the research could one day lead to improved methods for freezing human cells and organs so that tissues in cryostorage could remain alive and viable after thawing. When the temperature dips, some reptiles cannot escape to warmer areas, so several species instead have evolved incredible tolerance to cold. "Over the past 20 or more years of working in the field, various researchers, including ourselves, have come to realize that animals that survive long-term freezing as an integral part of their winter survival strategy have to be able to deal with ice penetration throughout their whole body and with the many consequences of this, including blood plasma freezing, heart beat and breathing stopping, etc.," said Janet Storey, a research associate at Carleton University's Institute of Biochemistry in Canada. © 2006 Discovery Communications Inc.

Keyword: Biological Rhythms
Link ID: 8634 - Posted: 06.24.2010

Andy Coghlan THE immune cells that attack the brains and nerves of people with multiple sclerosis could be turned into a weapon against the disease. This month sees the beginning of a trial of a personalised vaccine for MS, designed to rein in and destroy the renegade white blood cells that attack myelin cells lining the brain and nerves of patients. To make the vaccine, PharmaFrontiers of Woodlands, Texas, takes blood from an MS patient and extracts a sample of these renegade cells. The cells are then multiplied and weakened with radiation before being re-injected into the patient, whose immune system will then recognise them as damaged and attack them, sometimes wiping them out completely, according to the results of earlier trials. The immune system will also attack healthy renegade cells, which have the same markers on their surface. In one trial of 15 people with MS the rate of new flare-ups was reduced by 92 per cent. If this success is repeated in the new trial it might mean that regular shots could slow or even arrest progression of the disease. "If that's the case, the earlier we can do it after diagnosis the better," says David McWilliams of PharmaFrontiers. In the current trial, 100 patients will receive the treatment and 50 a dummy treatment. The vaccine would only need to be injected four times a year, while other MS drugs need to be given on a weekly or daily basis. © Copyright Reed Business Information Ltd.

Keyword: Multiple Sclerosis; Neuroimmunology
Link ID: 8633 - Posted: 06.24.2010

Bob Holmes The differences between humans and chimpanzees, which are genetically quite similar, may be down to the differences in the activity of individual genes in each species. That was the theory, but until now little has been known about how gene activity differs in different primates. To find out, Yoav Gilad, a human geneticist now at the University of Chicago, US, and his colleagues prepared a "gene chip" (a large array of genes) containing the same 1056 genes from humans, chimps, orang-utans and rhesus macaques. The researchers used the chip to measure the activity level of each of those genes in the four species. Any given pair of species differed in activity levels for 12% to 19% of the 907 genes for which they had good data for all four species. In particular, genes coding for transcription factors (proteins that regulate the activity of other genes) tended to be especially active in the human lineage. Gilad speculates that this may underlie the dramatic changes in body form and behaviour of humans compared to the other primates. © Copyright Reed Business Information Ltd

Keyword: Evolution; Genes & Behavior
Link ID: 8632 - Posted: 06.24.2010

Jacqueline Ruttimann Imitation may be the sincerest form of flattery, but for some it's about survival. Animals often avoid predators by copying the appearance of poisonous creatures. Usually the impostor tries to look like the most toxic species around, or imitates a range of toxic animals. But this is not so in the case of Ecuadorian frog Allobates zaparo. This frog chooses to mimic the less toxic of two local species. "It runs counter to traditional models," says Molly Cummings of the University of Texas, Austin, who describes the frog's strategy in this week's Nature1. The poison frogs Epipedobates bilinguis and Epipedobates parvulus share a similar warning sign: a bright red back. But the less poisonous and rarer of the two, E. bilinguis, also has yellow markings on its upper arms and thighs. Cummings found that when A. zaparo was found in the same region as one of these poisonous species, it would imitate that one. But in areas where all three species lived, A. zaparo tended to mimic E. bilinguis. This is odd. Mimics usually evolve to imitate the more abundant or more toxic species, says Cummings, because that normally guarantees the most protection. ©2006 Nature Publishing Group

Keyword: Neurotoxins; Evolution
Link ID: 8631 - Posted: 06.24.2010