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Cannabis use by children increases the risk of aggressive behaviour, but does not lead to them becoming withdrawn, a Dutch study says.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

PHILADELPHIA When Sylvia the baboon lost Sierra, her closest grooming partner and daughter, to a lion, she responded in a way that would be considered very human-like: she looked to friends for support. According to researchers from the University of Pennsylvania, baboons physiologically respond to bereavement in ways similar to humans, with an increase in stress hormones called glucocorticoids. Baboons can lower their glucocorticoid levels through friendly social contact, expanding their social network after the loss of specific close companions. "At the time of Sierra's death, we considered Sylvia to be the queen of mean. She is a very high-ranking, 23 year-old monkey who was, at best, disdainful of females other than Sierra," said Anne Engh, a postdoctoral researcher in Penn's Department of Biology. "With Sierra gone, Sylvia experienced what could only really be described as depression, corresponding with an increase in her glucocorticoid levels." Engh works with Penn biologist Dorothy Cheney and Robert Seyfarth, a professor in Penn's Department of Psychology. For the last 14 years, Cheney and Seyfarth have followed a troop of more than 80 free-ranging baboons in the Okavango Delta of Botswana. Their research explores the mechanisms that might be the basis of primate social relationships and how such relationships may have influenced the development of human social relationships, intelligence and language. Copyright © 2005, University of Pennsylvania

Keyword: Stress
Link ID: 8464 - Posted: 06.24.2010

Traditional polygraph tests to determine whether someone is lying may take a back seat to functional magnetic resonance imaging (fMRI), according to a study appearing in the February issue of Radiology. Researchers from Temple University Hospital in Philadelphia used fMRI to show how specific areas of the brain light up when a person tells a lie. "We have detected areas of the brain activated by deception and truth-telling by using a method that is verifiable against the current gold standard method of lie detection--the conventional polygraph," said lead author Feroze B. Mohamed, Ph.D., Associate Professor of Radiology at Temple. Dr. Mohamed explained how the standard polygraph test has failed to produce consistently reliable results, largely because it relies on outward manifestations of certain emotions that people feel when lying. These manifestations, including increased perspiration, changing body positions and subtle facial expressions, while natural, can be suppressed by a large enough number of people that the accuracy and consistency of the polygraph results are compromised. "Since brain activation is arguably less susceptible to being controlled by an individual, our research will hopefully eliminate the shortcomings of the conventional polygraph test and produce a new method of objective lie detection that can be used reliably in a courtroom or other setting," Dr. Mohamed said.

Keyword: Stress; Brain imaging
Link ID: 8463 - Posted: 01.31.2006

By Rossella Lorenzi, Discovery News Abraham Lincoln may have carried a genetic mutation responsible for the neurological disorder ataxia, according to U.S. researchers who screened descendants of the 16th president. Laura Ranum, a genetics professor at the University of Minnesota, and colleagues discovered that a type of ataxia, called Spinocerebellar ataxia type 5 (SCA5), is linked to a mutation in an amino-acid protein which plays an important role in maintaining the health of nerve cells. The gene breakthrough was made thanks to DNA from the Lincoln family: the researchers identified the mutation in an 11-generation family descended from the president's paternal grandparents, Capt. Abraham Lincoln and Bathsheba Herring. Overall, Ranum examined and collected DNA samples from 299 Lincoln family members and found that about a third have ataxia. "We are excited about this discovery because it provides a genetic test that will lead to improved patient diagnoses and gives us new insight into the causes of ataxia and other neurodegenerative diseases, an important step towards developing an effective treatment," Ranum said in a statement. © 2006 Discovery Communications Inc.

Keyword: Movement Disorders; Genes & Behavior
Link ID: 8462 - Posted: 06.24.2010

Stu Hutson The curative properties of stem cells may rely on prions, a new study suggests, the type of protein made infamous by mad cow disease. Prions are a special class of protein that can change the shape and function of other proteins around them. While these are found throughout any mammal’s body, the understanding of their biological role is limited. What is known is that prions that become misshapen, through some unknown process, can result in BSE (bovine spongiform encephalopathy) – mad cow disease – and its equivalents in other animals. Researchers at the Whitehead Institute in Cambridge, Massachusetts, US, have now found that adult stem cells in bone marrow gradually lose their ability to regenerate without their normal complement of membrane-bound prions. Stem cells are primitive cells which have the potential to divide endlessly, and the ability to differentiate into any cell type in the body – offering hope for future therapies. Andrew Steele, Cheng Cheng Zhang and colleagues used radiation to deplete the bone marrow of mice genetically engineered to not produce the prion proteins. The animals’ marrow regenerated quickly at first, but eventually slowed to a stop. The marrow also lost its regenerative abilities when transplanted into normal mice. © Copyright Reed Business Information Ltd

Keyword: Prions; Stem Cells
Link ID: 8461 - Posted: 06.24.2010

Highly analytical people, such as scientists who fall for each other, may be more likely to produce children with autism, an expert has argued. Professor Simon Baron-Cohen, of the University of Cambridge, said the phenomenon may help explain the recent rise in diagnoses. He believes the genes which make some analytical may also impair their social and communication skills. A weakness in these areas is the key characteristic of autism. It is thought that around one child in every 100 has a form of autism - the vast majority of those affected are boys. The number of diagnoses seems to be on the increase, but some argue this is simply because of a greater awareness of the condition. In a paper published in the journal Archives of Disease of Childhood, Professor Baron-Cohen labels people such as scientists, mathematicians and engineers as 'systemizers'. They are skilled at analysing systems - whether it be a vehicle, or a maths equation - to figure out how they work. But they also tend to be less interested in the social side of life, and can exhibit behaviour such as an obsession with detail - classic traits associated with autism. Professor Baron-Cohen argues that systemizers are often attracted to each other - and thus more likely to pass 'autism' genes to their offspring. He cited a survey of 1,000 members of the National Autistic Society which found fathers and grandfathers of children with autistic spectrum conditions are twice as likely to work in a systemizing profession. In addition, students in the natural sciences have a higher number of relatives with autism than do students in the humanities, and mathematicians have a higher rate of autistic spectrum conditions compared with the general population. (C)BBC

Keyword: Autism; Genes & Behavior
Link ID: 8460 - Posted: 01.30.2006

Andrew D. M. Smith Languages are constantly changing—being endlessly reinvented and reworked by the people who use them. In his compelling new book, The Unfolding of Language, Guy Deutscher argues that the same simple processes that underlie the rich and dynamic variety of modern human languages can also explain the initial emergence of complex language from its primitive beginnings. Deutscher, a specialist in ancient Semitic languages and a lecturer in linguistics at the University of Leiden in the Netherlands, notes that people have always complained about the state of their language, bemoaning its misuse (departures from "proper" language) and its degeneration from a once-glorious past into an error-ridden, chaotic mess. Even Cicero grumbled that the Latin of his time had deteriorated from that of the previous century. Deutscher explains that such complaints are depressingly inevitable, because "decay . . . is the aspect of change that is by far the most easily observable." But he also shows that, beneath the surface, the linguistic forces that conspire to erode language are closely related to the more elusive, but just as ineluctable, forces of renewal and reconstruction. Deutscher illuminates his absorbing analysis of humanity’s "greatest invention" with a detailed investigation of what he identifies as the three main forces of change: economy, expressiveness and analogy. The first of these, economy, occurs because speakers are intrinsically lazy and therefore seldom inclined to expend more effort in pronunciation than is absolutely necessary for the listener to understand their meaning. © Sigma Xi, The Scientific Research Society

Keyword: Language; Evolution
Link ID: 8459 - Posted: 06.24.2010

New study results bolster the controversial hypothesis that certain cases of obesity are contagious. Over the last 20 years, some research has suggested that certain strains of human and avian adenoviruses--responsible for ailments ranging from the chest colds to pink eye--actually make individuals build up more fat cells. Having antibodies to one strain in particular, so-called Ad-36, proved to correlate with the heaviest obese people and in one study, pairs of twins differed in heft depending on exposure to that virus. Now researchers have identified another strain of adenovirus that makes chickens plump. Physiologist Leah Whigham of the University of Wisconsin Madison and her colleagues inoculated young male chickens with three strains of adenovirus--Ad-2, Ad-31 and Ad-37. She and her team then monitored the chickens for three and a half weeks, recording their food intake throughout. Though the infected chickens and non-infected controls consumed the same amount of food and were exposed to the same conditions, chickens carrying Ad-37 were found to have nearly three times as much fat in their guts and more than two times as much fat over their entire body at the end of the three-and-a-half week period. The other two virus strains appeared to have little effect on weight. "Ad-37 is the third human adenovirus to increase adiposity in animals, but not all adenoviruses produce obesity," Whigham and her fellow authors write in their report presenting the findings in the current issue of the American Journal of Physiology. Although it remains unclear exactly how Ad-37 adds fat, it joins a growing list of such viruses, including canine distemper, Ad-5 and Ad-36. © 1996-2006 Scientific American, Inc.

Keyword: Obesity
Link ID: 8458 - Posted: 06.24.2010

Undamaged nerve fibres - not those that are injured - may cause long-term chronic pain, research suggests. Ongoing pain affects one-in-five adults across Europe, and costs an estimated £23 billion a year in lost work days. Inflammation caused by damaged nerve fibres triggered nearby undamaged ones to send signals to the brain, the University of Bristol researchers said. In the journal Neuroscience, they say their finding may aid the development of more effective painkillers. Ongoing pain is a burning or sharp stabbing/shooting pain that can occur spontaneously after nerve injury - unlike "evoked" pain caused, for example, by hitting your thumb with a hammer. It is particularly difficult to live with because it is often impossible to treat with currently available painkillers. Previous research into ongoing pain has tended to focus on the damaged nerve fibres after injury or disease and overlooked the intact fibres. Lead researcher Professor Sally Lawson said: "The cause of this ongoing pain and why it arises spontaneously was not understood before. Now that we know the type of nerve fibres involved, and especially that it is the undamaged fibres that cause this pain, we can examine them to find out what causes them to continually send impulses to the brain. This should help in the search for new analgesics that are effective for controlling ongoing pain." (C)BBC

Keyword: Pain & Touch
Link ID: 8457 - Posted: 01.28.2006