By MARY SPICUZZA About 8 p.m. on Wednesday, doctors at the Children's Hospital at Montefiore Medical Center had already finished more than 10 hours of grueling surgery to separate Carl and Clarence Aguirre, 2-year-old Filipino twins joined at the top of their heads, when they realized things were about to become even more complicated. The surgeons who were working to "tease apart" the boys' brains discovered they were actually fused. Until that moment, they thought the brothers had two separate brains that were tightly pressed together and linked only by veins. "We got to this point and we were stuck," said Dr. James T. Goodrich, the hospital's director of pediatric neurosurgery. "We did a lot of soul-searching at that point." After 90 minutes, the doctors decided to plunge ahead and separate the brains. Many hours later, the two boys lay side by side, each in his own bed, for the first time in their lives. Copyright 2004 The New York Times Company

Keyword: Development of the Brain
Link ID: 5960 - Posted: 08.07.2004

Nathan Seppa Amyloid beta, the waxy protein that litters the brains of Alzheimer's patients, is like a criminal with many arrests but no convictions. Studies have implicated amyloid plaques in the disease, but nobody has proved that they cause it. Now, scientists working with mice report that antibodies tailor-made to attack amyloid can wipe it out and reverse an experimental version of Alzheimer's disease if the intervention begins early enough. What's more, removing amyloid rubbed out its partner in crime, a protein called tau that collects in tangles inside brain cells. The work appears in the Aug. 5 Neuron. This study "provides the strongest experimental evidence to date" that amyloid is the ringleader of Alzheimer's disease, says coauthor Frank M. LaFerla, a neuroscientist at the University of California, Irvine. LaFerla suspects that amyloid collaborates with tau to kill neurons and trigger the confusion and memory loss that mark the disease. In their tests, LaFerla and his colleagues used mice genetically engineered to make excess amyloid and tau. The researchers then injected antibodies against amyloid into the animals' brains. Copyright ©2004 Science Service.

Keyword: Alzheimers
Link ID: 5959 - Posted: 06.24.2010

ITHACA, N.Y. -- If brain size is proportional to body size in virtually all vertebrate animals, Cornell University biologists reasoned, shouldn't eye size and body size scale the same way? While they failed to find a one-size-fits-all rule for eyes, what they learned about the 300 vertebrates they studied helps to explain how animals evolved precisely the orbs they need for everyday life. The biologists reported their findings in the journal Vision Research (August 2004, "The allometry and scaling of the size of vertebrate eyes"). Howard C. Howland, Stacey Merola and Jennifer R. Basarab say they did find a logarithmic relationship between animals' body weight and eye size for all vertebrates, in general: Bigger animals do tend to have bigger eyes, on average. But breaking vertebrates into smaller groups -- such as birds, fishes, reptiles and mammals -- and trying to predict their eye size gets more complicated. And dividing all mammals into groups -- such as rodents and primates -- could make a scientist cross-eyed: Compared with all vertebrates, rodents' eyes are only 61 percent as large as they "should be" if all animals obeyed the general rule, while primates' eyes are 35 percent larger than those of vertebrates as a whole. Except for gorillas, that is.

Keyword: Vision; Evolution
Link ID: 5958 - Posted: 08.07.2004

Every mom and dad can tell you that keeping children busy helps stave off cries of boredom--and now there is scientific backing to prove it. Dr. Anthony Chaston and his research colleague, Dr. Alan Kingstone, have proven, once and for all, that time really does fly when you're having fun. Or, at least, it flies when your attention is engaged. Working in the University of Alberta Department of Psychology, Chaston and Kingstone devised a test that required subjects to find specific items in various images--a sort of "Where's Waldo" activity. However, before the subjects started the test they were told that once they had completed it they would be asked to estimate how much time had passed during their test. There were seven levels of difficulty among the tests. In some cases, the items were easy to find because they were different colours from everything else, or the items were set among just one or two others. In the more difficult tests, the items were placed among many similar looking items, or they didn't even exist in the image, at all. "The harder and harder the search tasks were, the smaller and smaller the estimates became," said Chaston, whose study is published in the latest edition of Brain and Cognition. "The results were super clean--we have created a new and powerful paradigm to get at the link between time and attention."

Keyword: Attention
Link ID: 5957 - Posted: 08.07.2004

Many more people could become infected with vCJD than previously thought, experts have warned. It follows analysis of a probable transmission of the human form of BSE, via a blood transfusion. CJD Surveillance Unit scientists found the patient's genetic make-up differed from that of any other person so far diagnosed with the disease. This suggests that wider groups of people could be at risk than was thought, they write in the Lancet. Professor James Ironside, who led the research, told BBC News Online that just over half of the population were in the same genetic subgroup as the transfusion patient. He said the incubation period for the disease could be longer for this group, and it could also mean they were carrying the disease without being aware of it - but still potentially infecting others via blood transfusions or surgical instruments. (C)BBC

Keyword: Prions
Link ID: 5956 - Posted: 08.06.2004

Winged creature had birdlike senses, fossil X-rays reveal David Perlman, Chronicle Science Editor New evidence gathered from a major advance in X-ray imaging of fossils has established that the winged dinosaur called archaeopteryx could actually fly and had much the same sense of balance and sharp vision found in today's birds. And while its senses were a bit more primitive than its modern evolutionary descendants, the pigeon-sized archaeopteryx was certainly well equipped to navigate over land and forests looking for distant prey, scientists say. The evidence comes from a remarkable technology that allowed University of Texas researchers to scan in three dimensions deep inside the brain case of the priceless 247-million-year-old fossil dinosaur and reveal the workings of its most critical sense organs. The technique -- somewhat similar to computerized CAT scans that doctors use to examine the brains and bodies of their patients -- has resulted in the first complete 3-D models of the interior of the ancestral bird's brain, and an equally detailed cast of its inner ear. ©2004 San Francisco Chronicle |

Keyword: Evolution
Link ID: 5955 - Posted: 06.24.2010

Eighteen years after BSE first emerged in the UK, we still have little idea how to treat people who have contracted the human version, variant Creutzfeldt-Jakob Disease (vCJD). An investigation by New Scientist has revealed that the relatives of people with vCJD are frustrated by the slow progress being made to find new treatments. Time and effort are being wasted researching drugs that simply do not work, they say, while other, radical, treatments are not being made readily available. But while researchers privately disagree over which approaches show most promise, they say there is now a united effort to find a drug best able to save lives. Later this month, the UK government's Medical Research Council will officially launch a trial of potential treatments, after four years of argument over which to test. Called the "PRION-1" trial it will focus on quinacrine, an anti-malarial drug that showed early promise in treating various forms of CJD. The National Prion Disease Clinic at St Mary's Hospital in London has already given the drug to around 20 patients, but the results are not yet in. © Copyright Reed Business Information Ltd.

Keyword: Prions
Link ID: 5954 - Posted: 06.24.2010

Helen Pilcher Assertiveness really is all in the mind. Dominant rats have more new nerve cells in a key brain region than their subordinates, a study reveals. The finding hints that social hierarchies can influence brain structure, and raises questions over the use of standard animal behaviour tests in laboratory research. Yevgenia Kozorovitskiy and Elizabeth Gould from Princeton University, New Jersey, studied the brains of around 40 rats that had been left to form social hierarchies in a semi-natural setting. Their results are published in The Journal of Neuroscience1. In each experiment, four males and two females were placed inside a large box comprising an underground tangle of burrows and chambers and a feeding area above. Within three days, the males had established their preferred pecking order: an aggressive leader who attracted the females and three defensive subordinates. © 2004 Nature Publishing Group

Keyword: Neurogenesis
Link ID: 5953 - Posted: 06.24.2010

Experiments with mice hint that targeting one of the two molecular aggregates gumming up brains with Alzheimer’s disease also rids tissue of the other, as long as treatment starts early enough. This finding and a recent analysis of an interrupted Alzheimer’s vaccine trial in people have brought new life to the idea of immunotherapy for the debilitating disease. An ongoing debate in Alzheimer's research centers on the relative importance of brain plaques (extracellular clumps of a protein fragment called ß amyloid) and tangles (filaments of the protein tau that form inside neurons). Researchers have had difficulty testing the roles of plaques and tangles because no one had created mice that develop both--until last year, when neuroscientist Frank LaFerla of the University of California, Irvine, and colleagues engineered mice that develop plaques and tangles in the same brain regions as the brains of people with Alzheimer’s disease do. In the new work, the team injected antibodies against ß amyloid into the hippocampus of their transgenic mice when the animals were 1 year old. Three days after the injection, plaques in the injected animals had disappeared. Between 5 and 7 days after the injection, tau, which had aggregated within neurons but not yet formed tangles, also had melted away. Additional experiments with a different set of engineered mice suggested that the antibodies can't budge tangles once they have formed, however. Copyright © 2004 by the American Association for the Advancement of Science.

Keyword: Alzheimers
Link ID: 5952 - Posted: 06.24.2010

By Rossella Lorenzi, Discovery News — California ground squirrels heat up their tails to scare away hungry rattlesnakes, U.S. researchers have discovered. The behavior, which is the first deliberate animal signal known to be communicated via infrared radiation, takes advantage of rattlesnakes' ability to detect heat through sensitive structures in their faces called pit organs. "Rattlesnakes are a constant threat to California ground squirrels. Pups make up about 69 percent of the snakes' diet. Adults are not the prey, since they possess blood proteins which are capable of partially neutralizing the venom, allowing them to survive a bite," main researcher Aaron Rundus, of the University of California, Davis, told Discovery News. Due to the venom resistance and the need to defend their young, adult squirrels often confront snake predators with aggressive behaviors such as kicking sand, biting, swiping and most of all, brandishing their tails. "This is a unique snake elicited behavior. It consists of lifting the tail off the ground, piloerecting its fur and waving the tail side to side," Rundus said. Copyright © 2004 Discovery Communications Inc

Keyword: Evolution
Link ID: 5951 - Posted: 06.24.2010

Flight was built into the brain as well as the body of Archaeopteryx. The oldest known bird shares many skeletal features with its dinosaur ancestors, such as teeth and a long bony tail. Yet a CAT scan reveals that Archaeopteryx had the large brain and optic lobes of modern birds, not the brain of a dinosaur, says Angela Milner of the Natural History Museum in London, UK. It is relatively easy to study how a fossil skeleton may have been adapted for flight. However, navigating in a three-dimensional environment also requires a specialised brain. Modern birds have an enlarged brain, optic lobes and keen ears with spatial sensing organs, but little had been known about the brain of Archaeopteryx. So Milner’s team investigated the London specimen of Archaeopteryx, the only one suitable for scanning. A three-dimensional image created from the scan shows the bird had a relatively large cerebellum, “the area where all the coordination and control goes on”, Milner says. © Copyright Reed Business Information Ltd.

Keyword: Evolution; Brain imaging
Link ID: 5950 - Posted: 06.24.2010

Helen Pilcher Mothers who think they have longer to live are more likely to give birth to boys than girls, a survey of British women shows. The finding backs up the long-held theory that women may unwittingly be able to influence the sex of their unborn child. Sarah Johns from the University of Kent asked 609 first-time mothers, who had already given birth, to guess when they thought they would die. By subtracting the mother's age, she then calculated the number of years each woman thought she had left to live. The results are reported in the Proceedings of the Royal Society1. As the number of perceived years left rose, so too did the chance that they had had a son. Every extra year on the clock increased the odds of producing a male by 1%. The finding backs up a 30-year-old hypothesis2 that suggests women can bias the sex of their unborn babies, to enhance the chances of their genes being passed on to future generations. Boys need more looking after than girls, the theory says. So when food is scarce and resources are low, females preferentially give birth to girls because they are more likely to live through the hard times. But boys are able to produce more offspring, so when resources are plentiful, mothers should be more likely to give birth to boys, to maximise the number of potential grandchildren. ©2004 Nature Publishing Group

Keyword: Sexual Behavior; Neuroimmunology
Link ID: 5949 - Posted: 06.24.2010

Two related genes that help control signaling between brain cells may be central components of the biological machinery that causes cocaine addiction, researchers have found. Peter Kalivas and his colleagues found that deleting either of two genes in the Homer family in mice produced the same symptoms seen in withdrawal from cocaine. The researchers said that their findings could open a new research pathway to understanding how genetic susceptibility to addiction interacts with environmental factors to cause addiction. Studies by other researchers had suggested that the proteins produced by the Homer genes might play a role in cocaine addiction. Members of the family were known to be activated by cocaine, and reduction of activity in the genes had been linked to cocaine withdrawal. So, to unequivocally test the involvement of the Homer genes in cocaine addiction, Kalivas and his colleagues individually knocked out the genes in mutant mice and tested the behavioral and biological effects. In one behavioral test, they placed the knockout mice in one of two linked chambers after cocaine administration. One was a "comfortable" darkened chamber with nesting material, and the other was an "uncomfortable" bare, white, brightly lit chamber. The researchers found that the mice lacking Homer1 or Homer2 genes showed greater preference for the chamber that they associated with receiving cocaine, compared to normal controls. The knockout mice also showed hyperactivity characteristic of withdrawal.

Keyword: Drug Abuse; Genes & Behavior
Link ID: 5948 - Posted: 08.05.2004

Humans behave like small mammals when tracing the source of a low-pitched sound, according to a study funded by the Medical Research Council at University College London. UCL researchers have devised a new model for how the human brain tracks sound, which could eventually help engineers develop technology for tracking sound sources in noisy environments like crowded bars and restaurants. In the study published in this week's Nature, Dr David McAlpine and Nicol Harper asked volunteers to wander the streets of London wearing microphones in their ears. The microphones measured the time difference between sound arriving at each ear for a range of noises that people typically encounter in the city. While it was already known that animals and humans use small differences in the arrival time of sound at each ear to locate its source, the UCL study found that the human brain adopts a strategy similar to a barn owl's brain for sound pitches above middle-C, and a gerbil's below middle-C. David McAlpine says: "For animals and humans, locating the source of a sound can mean the difference between life and death, such as escaping a pursuer or crossing a busy street. Our study suggests that the brain adopts an efficient strategy for doing this, adapting to different frequencies, or pitches, of sound.

Keyword: Hearing
Link ID: 5947 - Posted: 08.05.2004

Inner ear size may be determinant A University of Toronto researcher has found that differences between men and women in determining spatial orientation may be the result of inner ear size. The study, published online in the journal Perception, examined whether differences in how men and women judge how we orient ourselves in our environment could be attributed to physiological or psychological causes. It found that giving the participants verbal instructions on how to determine their spatial orientation did not eliminate the differences between the sexes. "Since the instructions didn't remove the difference between how men and women judge spatial orientation, we believe it is likely a result of physiological differences," says Luc Tremblay, a professor in U of T's Faculty of Physical Education and Health. For example, says Tremblay, the otoliths – structures found in the inner ear which are sensitive to inertial forces such as gravity – tend to be larger in men than in women, and may allow males to adjust themselves more accurately than females in some environments. In the study, Tremblay asked 24 people (11 males and 13 females) to point a laser straight-ahead (perpendicular to the body orientation) while upright and when tilted 45 degrees backward. To test whether cognitive processes affected spatial orientation, participants – who were tested in the dark – were told to focus on external or internal cues to help them orient the laser. He found that although instructions to pay attention to internal cues helped women to point the laser significantly closer to their straight-ahead, there were still significant differences between the sexes, with women tending to look more towards their feet.

Keyword: Sexual Behavior; Hearing
Link ID: 5946 - Posted: 06.24.2010

A brain imaging study by the NIH's National Institute of Mental Health (NIMH) has found that an emotion-regulating brain circuit is overactive in people prone to depression — even when they are not depressed. Researchers discovered the abnormality in brains of those whose depressions relapsed when a key brain chemical messenger was experimentally reduced. Even when in remission, most subjects with a history of mood disorder experienced a temporary recurrence of symptoms when their brains were experimentally sapped of tryptophan, the chemical precursor of serotonin, the neurotransmitter that is boosted by antidepressants. Neither a placebo procedure in patients nor tryptophan depletion in healthy volunteers triggered the mood and brain activity changes. Brain scans revealed that a key emotion-processing circuit was overactive only in patients in remission — whether or not they had re-experienced symptoms — and not in controls. Since the abnormal activity did not reflect mood state, the finding suggests that tryptophan depletion unmasks an inborn trait associated with depression. Alexander Neumeister, M.D., Dennis Charney, M.D., Wayne Drevets, M.D., NIMH Mood and Anxiety Disorders Program, and colleagues, report on their positron emission tomography (PET) scan study in the August 2004 Archives of General Psychiatry. The NIMH researchers and others had previously shown that omitting tryptophan from a cocktail of several other essential amino acids washes out the precursor chemical from the blood and brain, depleting serotonin and often triggering symptoms in people with a history of depression — and even in healthy people from depression-prone families.

Keyword: Depression; Brain imaging
Link ID: 5945 - Posted: 06.24.2010

When Sydney Brenner gave his Nobel lecture in December 2002, he doffed his cap to the fourth joint-winner of the prize for physiology or medicine that year. In addition to himself and his two colleagues, John Sulston and Robert Horvitz, Brenner said that the honour should also be shared with Caenorhabditis elegans, without whom the others could not have made their groundbreaking discoveries. C. elegans is a barely visible nematode worm that, fully grown, reaches the magnificent length of 1mm. Possessing a fully functioning nervous system that consists of 302 nerve cells, it lives out its brief existence in compost heaps and river banks, sustaining itself on a diet of bacteria. But for Brenner, who in 1963 chose it as a model organism for studying how genes regulate development, the worm was the ultimate lab workhorse. "The animals live in a two-dimensional world feeding on E. coli on the surface of agar plates," he told his audience in Stockholm. "They are easy to grow in bulk, each animal producing about 300 progeny during a cycle." C. elegans quickly became a star, worthy of comparison with the mouse and the fruit fly for services to science. Brenner's early work linking genetic analysis to cell division and organ development laid the foundations for Sulston and Horvitz to identify key genes controlling that development - genes that have their counterparts in man. Among other things, their work has led to a greater understanding of many human diseases. © 2004 Independent Digital (UK) Ltd

Keyword: Development of the Brain
Link ID: 5944 - Posted: 06.24.2010

By DONALD G. McNEIL Jr. The first thing I did after spending 23 hours in a sleep laboratory was to head for a Starbucks and have a mocha-plus-extra-shot. It was truly heady - I hadn't felt so alert in years. But over the next couple of weeks, I became obsessed with my lack of sleep. I thought I could hear myself snore, and I would lie awake at 5 a.m., wondering what had woken me up. The lab, at Downstate Medical Center in Brooklyn, had diagnosed mild obstructive sleep apnea, a condition that blocks breathing and suppresses oxygen levels. In my case, the problem was probably caused by a narrow airway, an oversized uvula, "high normal" weight and drinking alcohol before bed. As a result, I suffered from chronic sleep deprivation leading to daytime grogginess. Dr. Chun Bai, the director of the sleep laboratory, had advised me to practice "better sleep hygiene." I should drink less wine with dinner, he said, go to bed earlier, use two pillows and sleep on my side. He also told me not to gain weight and to watch out when I drove at night. Copyright 2004 The New York Times Company

Keyword: Sleep
Link ID: 5943 - Posted: 08.04.2004

Levels of a particular hormone may influence a person's ability to cope with stress, suggests a study of soldiers put through a prisoner of war camp simulation. Soldiers enduring punishing stints in military survival school performed better and felt more attuned to their environments when they had higher levels of a hormone called dehydroepiandrosterone-S (DHEA-S), report US scientists. The ratio of DHEA-S against levels of another stress hormone, called cortisol, was important in coping with stress, they suggest. The researchers say DHEA-S could one day be given to people before stressful experiences to help them cope better during traumatic events. DHEA-S is secreted by the outer portion of the adrenal gland in response to stress. People aged 20 to 25 have the highest levels of DHEA-S, which then drops by a factor of five by age 80. Previous studies have shown the hormone enhances memory and reduces depression and aggression in mice. It turns up in low levels in people suffering from depression and anxiety, although its role in post-traumatic stress disorder (PTSD) has been unclear. © Copyright Reed Business Information Ltd.

Keyword: Stress; Hormones & Behavior
Link ID: 5942 - Posted: 06.24.2010

Jim Giles The state of suspended animation that astronauts enter during long-haul space flights is a staple of science-fiction movies. But now the European Space Agency (ESA) wants to turn it into reality. Agency staff are planning future research into the possibility of inducing a hibernation-like state in humans. "We are not sure whether it is possible," says Marco Biggiogera, an expert on hibernation mechanisms at the University of Pavia, Italy, who is advising ESA. "But it's not crazy." ESA believes hibernation would help astronauts to cope with the psychological demands of decades-long return journeys to destinations such as Saturn. And because less space and food would be needed on such missions, the spacecraft would be lighter and easier to launch. ©2004 Nature Publishing Group

Keyword: Sleep
Link ID: 5941 - Posted: 06.24.2010