By Jennifer Viegas, Discovery News — Humans who smell a pillow, shirt, shoe or other object that was in close contact with another person may be reminded of a certain someone. New research suggests squirrels have a similar ability to not only associate smells with particular squirrels, but to also create mental images of them. The study, published in this month's Animal Behavior, represents the first time the ability has been demonstrated in rodents. A second, not-yet-published study by other researchers indicates hamsters also have the skill. Like humans, squirrels must first be familiar with an individual before an odor can become associated with that other animal. A husband, for example, could smell his wife's perfume in an elevator and be reminded of her, but a perfume he has never smelled before could trigger no such memories. "Squirrels need to be familiar with others to be able to put all of an individual's odors into a representation of that individual, as if repeated interactions make that individual meaningful, and thus worthy of remembering at this level," explained Jill Mateo, who conducted the research. © 2006 Discovery Communications Inc

Keyword: Chemical Senses (Smell & Taste); Learning & Memory
Link ID: 8484 - Posted: 06.24.2010

UCI researchers have found that a single brief memory is actually processed differently in separate areas of the brain – an idea that until now scientists have only suspected to be true. The finding will influence how researchers examine the brain and could have implications for the treatment of memory disorders caused by disease or injury. The results were published this week in the early online edition of the Proceedings of the National Academy of Sciences. In a study using rats, researchers Emily L. Malin and James L. McGaugh of UCI’s Center for the Neurobiology of Learning and Memory demonstrate that while one part of the brain, the hippocampus, is involved in processing memory for context, the anterior cingulate cortex, a part of the cerebral cortex, is responsible for retaining memories involving unpleasant stimuli. A third area, the amygdala, located in the temporal lobe, consolidates memories more broadly and influences the storage of both contextual and unpleasant information. © Copyright 2002-2006 UC Regents

Keyword: Learning & Memory
Link ID: 8483 - Posted: 06.24.2010

New Haven, Conn.--Increasing the level of a protein that plays a key role in traumatic spinal cord injuries and multiple sclerosis reduces the concentration of disease-causing plaque in Alzheimer's disease, Yale School of Medicine researchers report in the Journal of Neuroscience. "Our new findings indicate that pharmacological methods to increase the protein, NogoReceptor, may be a way to treat the deficits associated with Alzheimer's disease," said Stephen Strittmatter, M.D., senior author of the study and co-director of the new program in Cellular Neuroscience, Neurodegeneration and Repair at Yale. It is well known that the clinical dementia of Alzheimer's disease is associated with specific pathological changes in the brain. One such change is deposits of the peptide beta-amyloid in brain plaques, a hallmark of the disease. Nerve fibers also play a crucial role in the neurodegenerative process of Alzheimer's disease. "We asked whether those mechanisms that regulate nerve fiber growth might lessen the Alzheimer's disease process," said Strittmatter, professor in the Departments of Neurology and Neurobiology. In brain sections from Alzheimer's patients, the protein NogoReceptor is distributed in an unusual pattern in conjunction with beta-amyloid peptide, which is the primary component of plaque that forms in the brains of patients with Alzheimer's disease, he said.

Keyword: Alzheimers
Link ID: 8482 - Posted: 02.03.2006

Roxanne Khamsi Just one sniff is all it takes for a rat to tell whether an odour comes from the left or the right, new research reveals, suggesting rats smell in stereo. The rodent impressed scientists in the lab by processing the location of a smell in a mere 50 milliseconds. Researchers have long sought to understand how human brains pick up on the source of a scent, but their experiments remain limited by the resolution of brain scanning technologies. Upinder Bhalla of the University of Agricultural Science in Bangalore, India, says that more precise tests can be conducted on rats, using specialised brain and nose probes. “In rats we can do the experiment definitively, monitoring exactly when they’re sniffing, “says Bhalla. Bhalla and his colleagues exposed rats to various odours and recorded information via probes in the animals’ olfactory bulb, the region of the brain called that first processes smells. They found that 90% of the cells in this brain region respond differently depending on whether a scent first enters the left or right nostril. © Copyright Reed Business Information Ltd.

Keyword: Chemical Senses (Smell & Taste)
Link ID: 8481 - Posted: 06.24.2010

An American study has suggested women with major depression risk a recurrence of their condition if they stop taking their drugs during pregnancy. It had been thought the hormone changes which occur during pregnancy gave a "protective" effect against depression. But the Journal of the American Medical Association study of 201 pregnant women found this was not true, and women who came off their medication relapsed. A UK expert agreed it was better for pregnant women to stay on their drugs. Dr Veronica O'Keane said the only exception was paroxetine, which a study last year suggested could be linked to birth defects. In this latest study, researchers from Massachusetts General Hospital and Harvard Medical School, Boston studied 201 pregnant women between 1999 and 2003, who were treated at centres which focussed on the care of psychiatric illness during pregnancy. All the participants had a history of major depression prior to pregnancy, were less than 16 weeks pregnant, and were either current or recent users of anti-depressants. Among women who maintained their medication throughout the pregnancy, 26% (21 out of 82) relapsed compared with 68% (44 out of 65) of those who discontinued their medication. (C)BBC

Keyword: Depression; Hormones & Behavior
Link ID: 8480 - Posted: 02.02.2006

By STEPHANIE COOPERMAN At 5-foot-10 and a mere 133 pounds, Mr. Johnson, 26, a laboratory research assistant in Columbus, Ohio, was mortified by his inability to gain weight. His friends scoffed: We wish we had your problem! Others were skeptical: Why don't you just eat more? Mr. Johnson had tried to bulk up before. Eight years earlier, when he was a student at the University of Mississippi, he was inspired to work out by his roommate, a 6-foot-2, 245-pound bodybuilder. "My arms were twigs," Mr. Johnson lamented. He collected books on weight lifting for guidance, reading many half a dozen times, and he lifted for two hours six days a week. In two years he added 15 pounds of muscle. But then his weight gain stalled. He was bigger, but not big enough. Finally last year Mr. Johnson went online and found what he couldn't get from any Arnold Schwarzenegger fitness manual: advice from people who also had trouble gaining and keeping muscle. He learned from discussion groups and blogs to take rest days between workouts to give his muscles time to recuperate and grow. He began carrying a kitchen timer so he would remember to eat six or seven times a day. Copyright 2006The New York Times Company

Keyword: Obesity
Link ID: 8479 - Posted: 02.02.2006

Scientists from the Whitehead Institute for Biomedical Research, Brandeis University and Massachusetts Institute of Technology report in the February 2 issue of the journal Neuron that increasing levels of brain derived neurotrophic factor (BDNF) alleviates symptoms in a mouse model of the childhood disorder Rett Syndrome. Rett Syndrome (RTT) is a severe neurological disorder diagnosed almost exclusively in girls. Children with RTT appear to develop normally until 6 to 18 months of age, when they enter a period of regression, losing speech and motor skills. Most develop repetitive hand movements, irregular breathing patterns, seizures and extreme motor control problems. RTT leaves its victims profoundly disabled, requiring maximum assistance with every aspect of daily living. There is no cure. In late 2003 Rudolf Jaenisch of the Whitehead Institute and Michael Greenberg of Children's Hospital Boston announced that the "Rett Syndrome gene", Mecp2, interacts with bdnf. Interestingly, BDNF is highly active in infants aged 6 to 18 months, the same age that RTT symptoms first appear. BDNF is essential for neural plasticity (ability of neural circuits to undergo changes in function or organization due to previous activity), learning and memory. BDNF is also implicated in other neurological disorders including Huntington's Disease, schizophrenia and depression.

Keyword: Development of the Brain; Trophic Factors
Link ID: 8478 - Posted: 02.02.2006

By Rossella Lorenzi, Discovery News — Neanderthals did not disappear because modern humans were better hunters and thus out-competed them for resources, according to U.S. and Israeli anthropologists. On the contrary, they were top predators who knew how to hunt the biggest and fastest of the animals. Neanderthals went extinct about 30,000 years ago, after having inhabited Europe and parts of Asia for roughly 200,000 years. The reason for their demise has been long debated and frequently attributed to modern humans' greater intelligence and consequently greater hunting skills. However, evidence from animal remains hunted by Neanderthals clearly indicates that these hominids were as good as any early modern humans at hunting, Daniel Adler, a paleoanthropologist at the University of Connecticut in Storrs, and colleagues report in the February issue of the journal Current Anthropology. The researchers examined abundant faunal remains, in particular thousands of bones belonging to a mountain goat species called the Caucasian tur that still exists today. The trove was excavated at Ortvale Klde, a rock shelter in the southern Caucasus in the Republic of Georgia dated to 60,000-20,000 years ago. Copyright © 2006 Discovery Communications Inc.

Keyword: Evolution
Link ID: 8477 - Posted: 06.24.2010

Anyone who has recognized a person but then struggled with the particulars – "I know I know her, but how…?" – can also appreciate the distinction between "familiarity" and "recollection." Recollection, as defined by memory specialists, is the ability to call up specific details about an encounter, while familiarity is simply knowing that someone or something has been encountered before. Both are elements of recognition memory and both, new research suggests, are functions of the brain's hippocampus. Published in the Feb. 2 issue of the journal Neuron, the University of California, San Diego study contradicts a recent body of work which maintains that the hippocampus is involved only in recollection. Led by senior researchers John Wixted, chair of the UCSD psychology department, and Larry Squire, a professor of psychiatry and neurosciences at the UCSD School of Medicine and the San Diego Veterans Affairs Health System, the study addresses one of the central debates in the neuroanatomy of memory. A seahorse-shaped structure in the left and right medial temporal lobes of the brain, the hippocampus has long been known as a critical area for processing memory. Memory is impaired, often severely, in people whose hippocampi have been damaged by trauma or disease – by Alzheimer's, for example, or oxygen deprivation following a heart attack.

Keyword: Learning & Memory
Link ID: 8476 - Posted: 06.24.2010

Cannabis use by children increases the risk of aggressive behaviour, but does not lead to them becoming withdrawn, a Dutch study says. Previous research on the drug has linked it to "internalised" problems such as depression. But the British Journal of Psychiatry study of 5,000 children said it was more likely to cause external problems such as delinquency and aggression. UK experts said the "jury was still out" about such an effect. The findings comes as figures show more UK children are being exposed to cannabis. Last year, a report by the Schools Health Education Unit, a government research team which has been tracking young people's experience of drugs since 1987, found over half of 14 and 15-year-olds had been offered cannabis, with one in four having taken it. The latest study, by a team at the Trimbos Institute, a mental health research centre in the Netherlands, analysed the results of questionnaires filled in by 5,551 young people aged 12 to 16. They found 17% had used the drug in the previous year. Researchers found the strength of the link increased with higher use of cannabis. However they found children who had used cannabis, but not in the previous year, were not at higher risk that those who had never used cannabis. They also found more heavy cannabis users - children who used the drug 40 times a year or more - reported poorer school grades than those who did not use the drug. (C)BBC

Keyword: Aggression; Drug Abuse
Link ID: 8475 - Posted: 02.01.2006

If doctors could put people in hibernation and pull them out at will, scientists think they could minimize damage from strokes, help recipients' bodies accept transplanted organs, perhaps even enable astronauts to travel in suspended animation until reaching distant destinations. But up to now, researchers have not understood the molecular mechanism controlling hibernation-like states. An HHMI-supported undergraduate's research, published in the January 2006 Journal of Neuroscience, describes for the first time the specific mechanism mice use to enter torpor, a hibernation-like state that enables them to survive periods of fasting during cool weather. Ross Smith is a co-author of the paper from researchers at Williams College in Williamstown, Massachusetts, and Emory University in Atlanta. Smith conducted the research as an undergraduate in Williams' biologist Steven J. Swoap's laboratory, as part of the college's HHMI-supported undergraduate science education program. A June 2005 graduate of Williams, Smith is now a technician in Gokhan Hotamisligil's laboratory at Harvard University. “We were trying to figure out what signaling pathway was involved in allowing mice to go in and out of torpor,” explained Smith. Working with Swoap, he helped show that torpor is controlled by the same system that controls fight-or-flight responses and further, that it involves the stimulation of receptors for epinephrine (adrenaline) and norepinephrine, called adrenergic receptors, most likely those found in fat stores. © 2006 Howard Hughes Medical Institute.

Keyword: Sleep; Biological Rhythms
Link ID: 8474 - Posted: 06.24.2010

The language we speak affects half of what we see, according to researchers at the University of California, Berkeley, and the University of Chicago. Scholars have long debated whether our native language affects how we perceive reality – and whether speakers of different languages might therefore see the world differently. The idea that language affects perception is controversial, and results have conflicted. A paper published this month in the Proceedings of the National Academy of Sciences supports the idea – but with a twist. The paper suggests that language affects perception in the right half of the visual field, but much less, if at all, in the left half. The paper, "Whorf Hypothesis is Supported in the Right Visual Field but not in the Left," by Aubrey Gilbert, Terry Regier, Paul Kay, and Richard Ivry – is the first to propose that language may shape just half of our visual world. Their finding is suggested by the organization of the brain, the researchers say. Language function is processed predominantly in the left hemisphere of the brain, which receives visual information directly from the right visual field. "So it would make sense for the language processes of the left hemisphere to influence perception more in the right half of the visual field than in the left half", said Terry Regier of the University of Chicago, who proposed the idea behind the study.

Keyword: Vision; Language
Link ID: 8473 - Posted: 06.24.2010

Helen Pearson Male monkeys gain weight during their partner's pregnancy, and this finding hints at a biological basis for expectant fathers' expanding waistlines. Men commonly mirror symptoms of pregnancy, such as weight gain, nausea and backache. But the phenomenon, sometimes called couvade syndrome, is often dismissed as psychosomatic, with no real physical explanation. Now, primate researcher Toni Ziegler at the University of Wisconsin-Madison and her colleagues have shown that two types of male monkeys experience one aspect of sympathetic pregnancy too. They weighed 14 male common marmosets (Callithrix jacchus) and 11 cottontop tamarins (Saguinus oedipus) during their partners' pregnancies of five and six months, respectively. They chose these animals because the males are monogamous and take on as much or more of the childcare as the mothers - just like some human dads. The animals gained as much as 20% of their original body weight, the team reports in Biology Letters. Fattening themselves in this way may help the male monkeys get through the gruelling few weeks after the baby arrives, Ziegler says, and so help ensure that their offspring survive. "We think it's preparing them," she says. ©2006 Nature Publishing Group

Keyword: Obesity; Sexual Behavior
Link ID: 8472 - Posted: 06.24.2010

Roxanne Khamsi The brains and spinal cords of male mice contain more of the protective, fatty substance called myelin, which insulates nerve cells, than their female counterparts, new research reveals. The finding could help to explain why some neurological diseases, including multiple sclerosis, strike one sex more than another. Robert Skoff of the Wayne State University School of Medicine in Detroit, US, and colleagues found an unexpected difference when they compared the composition of white matter in the brains of male and female mice. White matter consists of nerve cells coated with insulating myelin, which helps the cells to relay signals efficiently. Skoff’s team determined the density of oligodendrocytes – cells which produce myelin – in the male and female mouse central nervous system by testing for their molecular signature. They found that these specialised cells are roughly one-third more dense within the brains and spinal cords of male rodents. They add that the differences are present in young and old mice, and independent of strain and species. © Copyright Reed Business Information Ltd.

Keyword: Glia; Sexual Behavior
Link ID: 8471 - Posted: 06.24.2010

By Sandra G. Boodman The manufacturer of Zicam Cold Remedy has agreed to pay $12 million to settle 340 lawsuits brought by consumers who claim the popular over-the-counter zinc nasal gel damaged or destroyed their sense of smell. The Phoenix-based manufacturer, Matrixx Initatives, says the agreement announced Jan. 19 is not an admission of liability, but rather an effort to end most of the litigation over the homeopathic remedy. "The company still stands by the product, but this made good business sense," said Matrixx spokesman Robert J. Murphy. The agreement was announced jointly by the company and Arizona lawyer Charles S. Zimmerman, on behalf of a consortium of lawyers representing plaintiffs around the country. Like other scientific entrepreneurs, Robert Steven Davidson thought zinc might be a promising treatment for the common cold. But unlike many inventors of drugs, Davidson and his colleague Charles B. Hensley, who hold patents on Zicam, have unusual backgrounds. © Copyright 1996-2006 The Washington

Keyword: Chemical Senses (Smell & Taste)
Link ID: 8470 - Posted: 06.24.2010

Researchers at Melbourne's Howard Florey Institute have discovered how the brain prioritises pain and thirst in order to survive - a mechanism that helps elite athletes to 'push through the pain barrier'. The Florey's Dr Michael Farrell and colleagues discovered that pain sensitivity is enhanced when people are thirsty. The scientists also found that a part of the brain is uniquely activated when pain and thirst are experienced together, suggesting these regions may act as an integrative centre that has a special role in modifying pain senses. Dr Farrell used PET (Positron Emission Tomography) scans to examine changes in brain activity. The 10 individuals participating in the study were given saline injections to stimulate mild thirst and thumb pressure to induce mild pain. Although the level of thumb pressure remained constant throughout the tests, as people became thirstier, they felt more pain. Dr Farrell said the regions of the brain (the pregenual cingulate cortex and ventral orbitofrontal cortex) activated together during thirst and pain acted like a priority switch.

Keyword: Pain & Touch
Link ID: 8469 - Posted: 01.31.2006

By ANAHAD O'CONNOR THE FACTS Is there any link between childbirth and the lunar cycle? Many ancient cultures looked upon the moon as a sign of fertility, and since Roman times people have blamed full moons for all sorts of human behaviors, hence the word lunacy, from the Latin word for moon. But as mysterious and alluring as the link between full moons and births may sound, scientific studies suggest that it is more romance than reality. Over the years, more than a dozen different studies in several countries have looked for a connection, and almost all have found none. One of the most recent, published last year in The American Journal of Obstetrics and Gynecology, examined about 564,000 births across 62 lunar cycles in North Carolina between 1997 and 2001. The lunar cycle, the study found, had no predictable influence on deliveries or birth complications at all. Copyright 2006 The New York Times Company

Keyword: Biological Rhythms
Link ID: 8468 - Posted: 01.31.2006

By HENRY FOUNTAIN You can shout until you're hoarse, but you can't shout until you're deaf. One reason, scientists think, is a phenomenon called corollary discharge signaling. When your brain sends a signal to various muscles to speak, a copy of the signal goes to the auditory system, desensitizing it so it doesn't get overloaded. That's the idea, anyway. But very little is known about how corollary discharges work. Now James F. A. Poulet and Berthold Hedwig of the University of Cambridge in England have found a key to the puzzle. They studied crickets, however, not humans. "Crickets have a very simple nervous system and make very loud noises," said Dr. Poulet, who is now at the Federal Polytechnical School of Lausanne in Switzerland. Crickets do chirp very loudly — sound pressure levels have been measured at more than 100 decibels — yet they don't deafen themselves. Several years ago, Dr. Poulet and Dr. Hedwig discovered that at the precise instant a cricket moved its forewing muscles to create a chirp, its auditory neurons became inhibited, or desensitized, presumably by some chemical neurotransmitter. "We knew that the inhibition was being generated somewhere in the nervous system, but we didn't know where," Dr. Poulet said. Copyright 2006 The New York Times Company

Keyword: Hearing
Link ID: 8467 - Posted: 06.24.2010

By RONI RABIN Candace Talmadge was determined to get through menopause without using hormones, and she tried just about every alternative treatment she could find, like soy tablets, herbs and acupuncture, a chiropractor and even an anti-anxiety medication. "There are always risks to any medication you take, whether it's traditional or nontraditional," said Ms. Talmadge, 51, an author from Lancaster, Tex. "But I've been going through hell. I think my doctor's attitude was, 'Do the benefits for you, right now, outweigh the risks?' " Three and a half years after a landmark study stunned physicians by finding that hormone therapy had serious risks and did not prevent heart disease in postmenopausal women, many women continue to turn to hormones for relief. Many gynecologists continue to prescribe them as a first-line therapy for severe menopausal symptoms. Debates over the study's findings remain heated, with doctors divided between those who believe in the power of hormone therapy to protect the heart and relieve menopausal symptoms and those who think that any heart benefits have been discredited. Copyright 2006 The New York Times Company

Keyword: Hormones & Behavior
Link ID: 8466 - Posted: 01.31.2006

Changes in the brain that are important indicators of bipolar disorder are not prominent until young adulthood and are reduced in persons taking mood-stabilizing medications, Yale School of Medicine researchers report this month in Biological Psychiatry. The researchers used magnetic resonance imaging to measure a part of the brain that regulates emotions, the ventral prefrontal cortex, that lies above the eyes. The changes in persons with bipolar disorder were not prominent until young adulthood, suggesting that the illness progresses during the teenage years. Bipolar disorder is also known as manic-depressive illness. "The brain changes were diminished in persons with bipolar disorder who were taking mood-stabilizing medications," said Hilary Blumberg, M.D., associate professor in the Department of Psychiatry and director of Yale's Mood Disorders Research Program. "This brings hope that it may someday be possible to halt the progression of the disorder." Blumberg added, "Research to understand bipolar disorder in youths is especially important because of their high risk for suicide."

Keyword: Schizophrenia; Depression
Link ID: 8465 - Posted: 01.31.2006