Birds are not renowned for their sense of smell. But new research shows that a species of seabird prefers the scent of its mate to those of other individuals in the colony. The odors may help the birds locate their burrows and, perhaps, even choose a partner. Each year, seabirds called Antarctic prions return to breeding colonies on sub-Antarctic islands with their lifelong mates. The pairs build shallow burrows and then split the duty of incubating the eggs, spending the rest of their time looking for food. Because prions can locate their own burrows among those of hundreds of neighbors in the middle of the night, researchers Francesco Bonadonna, an animal behaviorist at the French national research center CNRS in Montpellier, France, and Gabrielle Nevitt, a sensory ecologist at the University of California, Davis, began to suspect that they were using odor cues. To test their hypothesis, the pair put birds in a "Y"-shaped maze and placed cotton bags (originally used to transport the musky-scented prions) at the end of each tunnel, providing the birds with a choice of odor. The seabirds preferred the smell of their mates over odors from other prions in the colony. To ensure that the seabirds weren't just choosing the more familiar odor, the researchers then tested whether the prions would pick their own odor over that of another colony member. In that case, the prions avoided their own smell in favor of the other, more novel odor, the researchers report in the 29 October issue of Science. The results provide strong evidence that the prion's olfactory system is developed enough to identify their mates just based on smell, says Bonadonna, suggesting that they may also be able to sniff their way home. Copyright © 2004 by the American Association for the Advancement of Science.

Keyword: Chemical Senses (Smell & Taste); Sexual Behavior
Link ID: 6353 - Posted: 06.24.2010

An errant enzyme linked to bipolar disorder, in the brain's prefrontal cortex, impairs cognition under stress, an animal study shows. The disturbed thinking, impaired judgment, impulsivity, and distractibility seen in mania, a destructive phase of bipolar disorder, may be traceable to overactivity of protein kinase C (PKC), suggests the study, funded by the National Institutes of Health's (NIH) National Institute of Mental Health (NIMH) and National Institute on Aging (NIA), and the Stanley Foundation. It explains how even mild stress can worsen cognitive symptoms, as occurs in bipolar disoder, which affects two million Americans. Abnormalities in the cascade of events that trigger PKC have also been implicated in schizophrenia. Amy Arnsten, Ph.D. and Shari Birnbaum, Ph.D. of Yale University, and Husseini Manji, M.D., of NIMH, and colleagues, report on their discovery in the October 29, 2004 issue of Science. "Either direct or indirect activation of PKC dramatically impaired the cognitive functions of the prefrontal cortex, a higher brain region that allows us to appropriately guide our behavior, thoughts and emotions," explained Arnsten. "PKC activation led to a reduction in memory-related cell firing, the code cells use to hold information in mind from moment-to-moment. Exposure to mild stress activated PKC and resulted in prefrontal dysfunction, while inhibiting PKC protected cognitive function."

Keyword: Stress; Schizophrenia
Link ID: 6352 - Posted: 10.30.2004

By Jennifer Viegas, Discovery News — Male bats with a natural talent for singing attract more female admirers, and some males and females even sing in secret, using sounds that are inaudible to humans and to other animals, two new studies of bats reveal. The studies, both published recently in the journal Animal Behavior, reveal that bat communication systems, as well as their social lives, are far more complex than thought. For the first study, biologists Susan Davidson and Gerald Wilkinson of the University of Maryland analyzed songs and other sounds produced by greater white-lined bats, Saccopteryx bilineata, located in Trinidad, in the West Indies. They also videotaped these bats in the wild to see how their calls and songs might influence behavior. Greater white-lined male bats sing what the researchers refer to as bat "love songs." Female bats of the species just produce short calls. Davidson and Wilkinson first determined that male songs consist of separate sounds, or mini tunes, within the overall vocalization. They classified these songs as being screechy, whiny, a combo screech-whine, short repeated notes, and long tonal sounds with some harmonics. Copyright © 2004 Discovery Communications Inc

Keyword: Hearing; Sexual Behavior
Link ID: 6351 - Posted: 06.24.2010

Dolphins have evolved surprisingly big brains over the last 47 million years, according to the largest fossil study ever done on the animals. The growth - which occurred in two spurts - may shed light on how humans became so brainy. Dolphins are famously bright, performing mental feats few other animals can, such as recognising themselves in mirrors. That intelligence is probably due to their exceptionally large brains - some dolphin species boast brain-to-body mass ratios second only to humans. But how they evolved such big brains has been a mystery. Now, a trio of researchers led by biologist Lori Marino at Emory University in Atlanta, Georgia, US, has tracked how dolphins evolved their big brains using the fossil record. After four years of scouring museum collections, the team turned up 66 fossilised skulls of dolphin ancestors - adding to only five studied previously. They probed the specimens' brain sizes with computed tomography (CT) scans and estimated the animals' body masses by analysing the size of bones around the base of the skulls. They studied the fossilised skulls - dating back 47 million years - along with 144 modern specimens, and found each creature’s encephalisation quotient (EQ). This measurement relates a specimen's brain mass to that of an average animal of similar size, so if an animal's EQ is less than 1, it has a smaller than average brain, while if it is greater than 1, it has a relatively large one. Humans are the brainiest of all creatures, with an EQ of 7. © Copyright Reed Business Information Ltd.

Keyword: Evolution; Intelligence
Link ID: 6350 - Posted: 06.24.2010

Christen Brownlee Prescribing antidepressants to children and pregnant women is becoming increasingly common. However, it hasn't been clear whether these medications pose a risk to the developing brain. In a new study, researchers provide evidence that, in young mice, the antidepressants known as selective serotonin reuptake inhibitors (SSRIs) permanently alter the brain, resulting in a greater risk of depression and anxiety in adulthood. SSRIs seem to combat depression by affecting a molecule, called a transporter, on the surface of some brain cells. The molecule's main role is to absorb serotonin, a brain chemical that regulates mood. SSRIs probably prevent the transporter from taking in serotonin, thereby increasing the amount of free serotonin in the brain and lightening a person's disposition. Jay Gingrich and his colleagues at Columbia University had previously shown that mice engineered to be missing a gene for the serotonin transporter show anxiety and depression once they reach adulthood. The mood problems of these knockout mice were unexpected, Gingrich says, because when SSRIs inactivate the serotonin transporter in normal, mature mice, they ease depression symptoms, as they do in people. Copyright ©2004 Science Service.

Keyword: Depression; Development of the Brain
Link ID: 6349 - Posted: 06.24.2010

A transporter protein that vacuums up the neurotransmitter glutamate has a structure radically different from any other membrane protein studied to date. Researchers are excited about the studies because they hope they will further illuminate the activity of glutamate transporters, proteins that shuttle the critical neurotransmitter between nerve cells. The Howard Hughes Medical Institute (HHMI) researchers who determined the first-ever three-dimensional structure of such a neurotransmitter transporter found that the protein possesses a bowl shape that inserts deep into the cell membrane. The structure shows that the bowl contains protein segments that behave like flippers in a pinball machine to trap glutamate and retrieve it into the neuron. Glutamate-triggered neurons play a central role in learning and memory. Their dysfunction has been implicated in a wide range of disorders, including schizophrenia, depression and stroke, said HHMI investigator Eric Gouaux, who led the research team. Gouaux and co-lead authors Dinesh Yernool and Olga Boudker at Columbia University published their findings in the October 14, 2004, issue of the journal Nature. © 2004 Howard Hughes Medical Institute.

Keyword: Learning & Memory
Link ID: 6348 - Posted: 06.24.2010

By Randy Dotinga SAN DIEGO -- Three decades after researchers first fathomed the unusual brain power of songbirds, scientists are devoting big chunks of their careers to finches and canaries, hoping to understand how they manage to be among the only species that learn how to make new sounds. Even though their brains range from just the size of a grain of rice to peanut-size, some types of songbirds can still pick up hundreds of songs during their lives. They improvise the songs like miniature jazz singers and even develop regional accents depending on where they live. Today's the Day. Scientists at this week's annual Society for Neuroscience convention in San Diego said research into bird songs can lead to greater understanding of human speech and the mysteries of how animals develop new neurons and memorize things. It helps that bird brains are small, leaving few places for singing abilities to hide. "We know the human brain is capable of this, but we don't know where to look for it," said Peter Marler, professor emeritus of neurobiology at the University of California at Davis, who helped pioneer the study of songbirds in the early 1970s. "We know virtually nothing about the detailed circuitry," © Copyright 2004, Lycos, Inc.

Keyword: Language; Sexual Behavior
Link ID: 6347 - Posted: 06.24.2010

Overactivity of protein kinase C (PKC), an enzyme that is implicated in bipolar disorder and schizophrenia, markedly impairs higher brain functions in animals, according to a Yale study published Oct. 29 in Science. The research adds to mounting evidence that excessive activity of PKC may underlie the distractibility, impaired judgment, impulsivity, and disturbed thinking seen in bipolar disorder (also known as manic depressive illness), and in schizophrenia. The study also shows that exposure to mild stress can activate PKC, which may lead to worsening of symptoms in patients with these disorders. The findings may explain how upsetting events in the environment can lead to deterioration in higher brain function, and why patients with schizophrenia or bipolar disorder may be particularly susceptible to stress-induced dysfunction. PKC inhibitors may be useful in treating these illnesses, according to Amy Arnsten, associate professor, Department of Neurobiology at Yale School of Medicine and senior author of the study. "These new findings may also help us understand the impulsivity and distractibility observed in children with lead poisoning," Arnsten said. "Very low levels of lead can activate PKC, and this may lead to impaired regulation of behavior."

Keyword: Schizophrenia
Link ID: 6346 - Posted: 10.29.2004

St. Louis,-- In a finding that may one day help researchers better understand age-related memory and hearing loss, scientists have shown that two key nervous system proteins interact in a manner that helps regulate the transmission of signals in the nervous system. Researchers report online in Nature Neuroscience that they've connected neuregulin-1 (Nrg-1), a protein linked to schizophrenia, and postsynaptic density protein-95 (PSD-95), a protein associated with Alzheimer's disease. The print version appears during the first week of November. Nrg-1 originally caught scientists' attention because of its links to processes that encode memory in nerve cells. Scientists later found mutations in the Nrg-1 gene increased risk of schizophrenia in Scottish and Icelandic populations. Nrg-1 is positioned in the outer membrane of nerve cells, with a portion hanging outside the nerve cell and another part jutting inside it. The exterior portion, known as Nrg-ECD, contributes to the formation of synapses, areas where two nerve cells communicate across a small physical gap, and to other aspects of nervous system development and communication. Until recently, researchers gave little attention to Nrg-ICD, the interior portion of Nrg-1. But Jianxin Bao, Ph.D., research assistant professor of otolaryngology at Washington University and other scientists have begun amassing evidence that Nrg-ICD might be as important or even more important than Nrg-ECD.

Keyword: Learning & Memory; Hearing
Link ID: 6345 - Posted: 10.29.2004

Emma Marris Darwin famously realized that the eye would be a key test for his theory of evolution by natural selection. He suggested gradual steps from an "imperfect and simple" form, and modern scientists have no trouble believing that the eye evolved from a single light-detecting cell. But they disagree over whether it evolved just once, or many times. Now the miniscule marine worm Platynereis dumerilii, whose crude light perception seems to have stood it in good stead for millennia, hints at an answer to this question. Its few light-sensing cells come in two types: one is of a type seen almost exclusively in vertebrates, and one is seen in insects, according to a paper in this week's Science. Could a worm like Platynereis have been the father of the eye? Insect eyes are known to consist of an array of compound lenses, whereas vertebrate eyes contain a single lens. But they are also made of different types of cells: insects' eyes are built up with cells called rhabdomeric photoreceptors; vertebrates use ciliary photoreceptors. ©2004 Nature Publishing Group

Keyword: Vision; Evolution
Link ID: 6344 - Posted: 06.24.2010

By Bruce Lieberman, UNION-TRIBUNE STAFF WRITER Biologists at UCSD have discovered a chemical critical for the development of sight in the developing brain. The discovery, scientists said yesterday at the Society for Neuroscience meeting in San Diego, could provide a new understanding of many vision disorders, including congenital birth defects and those resulting from injury. Scientists have known that development of the vision system, from the retina of the eye to the brain circuits that carry visual signals from the eye to the brain, relies on the coordinated firing of cells in the developing fetus. But what prompts this patterned activity has been unknown, until now. In their work discussed yesterday, UC San Diego researchers Marla Feller and Chuh-Tien Wang detailed their evidence that the chemical messenger adenosine controls the timing of bursts of electrical activity in the developing nervous system of a fetus. "The waves of neural activity in the developing visual system have a remarkably stereotyped temporal pattern," said Feller, an assistant professor of biology who led the study. "We show that the neurotransmitter adenosine may control this pattern by altering the excitability of cells in the retina." © Copyright 2004 Union-Tribune Publishing Co.

Keyword: Vision; Development of the Brain
Link ID: 6343 - Posted: 06.24.2010

-- Robert Preidt THURSDAY, (HealthDayNews) -- Men who are given testosterone-deprivation treatment for prostate cancer forget things faster than healthy men, says a study by Oregon Health & Science University researchers. The researchers found that word retention among men undergoing testosterone deprivation decreased rapidly only two minutes after they learned words, even though they were able to initially learn words as well as healthy men. This rapid decline in memory suggests that the lack of testosterone impacts the function of the hippocampus, the part of the brain that controls learning and memory. "When you look at their memory, they're perfectly normal when they're immediately asked to recall something, but they can't hold or save the information as well in order to recall it over a retention interval, over a period of time. They're faster at forgetting," study co-author Jeri Janowsky, a professor of behavioral neuroscience and neurology, said in a prepared statement. © 2004 Forbes.com Inc.

Keyword: Learning & Memory; Hormones & Behavior
Link ID: 6342 - Posted: 06.24.2010

A potential new therapeutic approach to Alzheimer's disease protects brain cells in culture by drastically reducing the neurotoxic amyloid protein aggregates that are critical to the development of the disease. The treatment involves dispatching a small molecule into the cell to enlist the aid of a larger “chaperone” protein to block the accumulation of the brain-clogging protein. The new “Trojan horse” technique overcomes a major challenge in drug design - namely, the limited ability of molecules small enough to enter a cell to interfere with interactions between much larger proteins. The researchers said it might also be possible to use this new approach to sabotage proteins central to pathogenic organisms, such as human immunodeficiency virus (HIV). Led by Howard Hughes Medical Institute investigator Gerald R. Crabtree, the researchers reported their findings in the October 29, 2004, issue of the journal Science. First author Jason Gestwicki and senior author Isabella Graef are both members of Crabtree's laboratory at Stanford University School of Medicine. The plaques that clog the brains of people with Alzheimer's disease develop through the buildup of amyloid protein chains from individual units called Aß peptide. “There have been many attempts by pharmaceutical companies to develop Aß peptide inhibitors — mainly by screening for small molecules that would bind to those aggregates and hoping that they would prevent further aggregation,” said Crabtree. “But instead, what happens in virtually all cases is that those molecules just fit right into the aggregates and don't prevent aggregation at workable concentrations.” © 2004 Howard Hughes Medical Institute.

Keyword: Alzheimers
Link ID: 6341 - Posted: 06.24.2010

By Richard Shim and Ina Fried There's no mistaking what they study at the Redwood Neuroscience Institute. There are brains all over the place. From the colorful pictures of brain coral that hang on the walls to the promotional key chains sporting little plastic cerebral cortices, you'd have to be gray-matterless not to notice the decorative theme at this nonprofit scientific research organization. Though it may all seem a little over the top to the average visitor, such brain mania seems excusable for someone who's spent about 25 years studying the workings of this most thoughtful of organs. The institute's director, Jeff Hawkins, was interested in the brain even before he helped spawn an industry with his most famous invention, the PalmPilot. In his spare time, he learned the sciences behind brain research, and after becoming versed in them he developed his own theory, which is contrary to some of the established ideas. In his first book, "On Intelligence," Hawkins explains his theory and how it can be used to build truly smart machines--a question others have tackled, through the study of artificial intelligence and neural networks, but haven't resolved. Hawkins says the main difference between his idea and others is that the other methods try to copy human behavior using the wrong notion of how the brain works. The brain doesn't produce an output for every input, Hawkins says. Instead, it stores experiences and sequences and makes predictions based on those memories. Using that realization about intelligence as a starting point, scientists and inventors can create new and smarter machines, he says. ©2004 CNET Networks, Inc.

Keyword: Learning & Memory; Intelligence
Link ID: 6340 - Posted: 06.24.2010

Three years ago Elisabeth Bryant believed she would be blind for the rest of her life. “I couldn’t see anything,” she says. Now, although her vision is not perfect, she can see well enough to read, play computer games and check emails. Bryant has retinitis pigmentosa, an eye disease that has blinded four generations of her family. What has saved the sight in one of her eyes is a transplant of a sheet of retinal cells. The vision in this eye has improved from 20:800 to 20:84 in the two-and-a-half years since the transplant – a remarkable transformation. So far, six patients with either advanced retinitis pigmentosa or macular degeneration have had similar transplants. Together, these degenerative diseases are the biggest cause of blindness in rich countries, affecting tens of millions of people. While Bryant’s improvement is the most dramatic, four other patients have also had good results. When New Scientist print edition (1 February, 2003) reported the initial results of these retinal transplants, experts cautioned that the results could be due to the rescue effect: a short-term improvement triggered by the release of growth factors after eye surgery. That appears increasingly unlikely, because the rescue effect usually lasts only months. © Copyright Reed Business Information Ltd.

Keyword: Stem Cells; Vision
Link ID: 6339 - Posted: 06.24.2010

Nashville, Tenn. – Biomedical engineers and physicians at Vanderbilt University have brought the day when artificial limbs will be controlled directly by the brain considerably closer by discovering a method that uses laser light, rather than electricity, to stimulate and control nerve cells. The researchers have discovered that low-intensity infrared laser light can spark specific nerves to life, exciting a leg or even individual toes without actually touching the nerve cells. “This technique brings nerve stimulation out of the Dark Ages,” said Vanderbilt Assistant Professor of Biomedical Engineering and Neurological Surgery Anita Mahadevan-Jansen. “Much work is going on around the world trying to make electric nerve stimulation better, but the technique is inherently limited. Using lasers instead, we can simultaneously excite and record the responses of nerve fibers with much greater precision, accuracy and effectiveness.” The method was developed by Mahadevan-Jansen; her husband Duco Jansen, associate professor of biomedical engineering and neurological surgery; Dr. Peter Konrad and Dr. Chris Kao of Vanderbilt Neurological Surgery, both assistant professors of neurological surgery; and biomedical engineering doctoral student Jonathon Wells. Copyright 2004 Vanderbilt University

Keyword: Miscellaneous
Link ID: 6338 - Posted: 06.24.2010

Christopher Reeve, best known for his role as Superman, remained in the limelight in recent years as an advocate of increased funding and research for spinal cord injuries and other central nervous system disorders. Left paralyzed from the neck down by a fall from his horse in 1995, Reeve focused his efforts through the Christopher Reeve Paralysis Foundation. He was one of an estimated 250,000 people in the U.S. living with spinal cord injuries. Martin Schwab, a neuroscientist at The Brain Research Institute at the University of Zurich, Switzerland, and an international team of researchers have spent much of the last twenty years studying why the nerve fibers of the spinal cord and the brain don't re-grow or regenerate themselves after injury in the same way as other tissues of the body. "If you destroy a large part of the muscle tissue in a muscle, or of your liver, this tissue can re-generate," Schwab explains. "This is what is not occurring in the central nervous system." During early childhood development, the nervous system, which consists of around 10 billion nerve cells, each one having between a thousand and ten thousand connections with other nerve cells, develops and forms an incredibly complex network. Having become stabilized, the adult central nervous system—the brain and the spinal cord—are relatively hard-wired, allowing only small changes during learning or adaptation. So when part of this system is damaged by injury or disease such as stroke, the loss of function associated with the damage is permanent. "Once you are paraplegic due to an accident which has injured your spinal cord, you remain in a wheelchair all your life," Schwab says. © ScienCentral, 2000- 2004.

Keyword: Regeneration
Link ID: 6337 - Posted: 06.24.2010

There is new scientific evidence to support the time-honored advice to students cramming for exams to get themselves a good night's sleep after studying. Researchers who analyzed brain activity in sleeping volunteers who had learned to navigate through a computer-generated virtual town have discovered evidence that spatial memories are consolidated during deep sleep. Also, the researchers say that they have shown for the first time that the activity level in the brain's learning center, the hippocampus, correlates with the improvement in memory performance when the subjects are tested the next day. According to Philippe Peigneux and his colleagues, "A growing body of experimental evidence shows the influence of sleep on the consolidation of recent memory traces. The underlying hypothesis posits that the information that is acquired during wakefulness is actively altered, restructured, and strengthened during sleep." However, they said, exploring this consolidation process was difficult because of the complexities of both sleep and memory. For example, sleep consists of two major stages -- rapid eye movement (REM) sleep and non rapid eye movement (NREM) sleep. Evidence from animal studies of learning and sleep indicated that spatial memories seem to be replayed in the hippocampus during the deep "slow wave sleep" (SWS) during the NREM sleep stage.

Keyword: Sleep; Learning & Memory
Link ID: 6336 - Posted: 10.28.2004

Washington, DC – New findings from researchers at Georgetown University Medical Center in collaboration with Wake Forest University School of Medicine have shown that there is hope for individuals suffering a life-long history of reading problems. Using brain imaging technology the research group showed how the adult dyslexic brain responds to a specific phonological-based reading intervention program responsible for reading skill improvement. Published in the October 28 issue of the Journal Neuron, this is the first research study to examine the brain systems related to successful phonological-based instruction in dyslexic adults. "Reading is one of the most important skills we learn – it affects virtually every aspect of a person's life," said Dr. Guinevere Eden, associate professor of pediatrics, director of Georgetown University's Center for the Study of Learning, and lead author of the study. "Despite the fact that the majority of individuals with dyslexia are adults, little is known about the biological basis of how they can improve their reading skills. We need to understand the neural mechanisms behind these research-based reading instructions so that we can achieve a deeper understanding of precisely how these interventions work. Our findings suggest that the brain mechanisms used by adult dyslexics might be different from those observed when young children undergo remediation, a strong indication that there will never be a 'one size fits all' approach to helping dyslexics become proficient readers."

Keyword: Dyslexia
Link ID: 6335 - Posted: 06.24.2010

Rex Dalton A new human-like species - a dwarfed relative who lived just 18,000 years ago in the company of pygmy elephants and giant lizards - has been discovered in Indonesia. Skeletal remains show that the hominins, nicknamed 'hobbits' by some of their discoverers, were only one metre tall, had a brain one-third the size of that of modern humans, and lived on an isolated island long after Homo sapiens had migrated through the South Pacific region. "My jaw dropped to my knees," says Peter Brown, one of the lead authors and a palaeoanthropologist at the University of New England in Armidale, Australia. The find has excited researchers with its implications - if unexpected branches of humanity are still being found today, and lived so recently, then who knows what else might be out there? The species' diminutive stature indicates that humans are subject to the same evolutionary forces that made other mammals shrink to dwarf size when in genetic isolation and under ecological pressure, such as on an island with limited resources. The new species, reported this week in Nature, was found by Australian and Indonesian scientists in a rock shelter called Liang Bua on the island of Flores. The team unearthed a near-complete skeleton, thought to be a female, including the skull, jaw and most teeth, along with bones and teeth from at least seven other individuals. In the same site they also found bones from Komodo dragons and an extinct pygmy elephant called Stegodon. ©2004 Nature Publishing Group

Keyword: Evolution
Link ID: 6334 - Posted: 06.24.2010