By Phil Plait Our brains are massively complex machines, constantly processing huge amounts of data from our senses. Our eyes provide most of that input; they send a huge amount of information to the brain, and it’s actually rather astonishing we can figure anything out from it. Given that, our ability to detect motion is pretty amazing. Despite all that noise, if something moves, something changes, our brain targets right on it. To see motion, you need at least two objects, so that one can move relative to the other. Sometimes, one of those objects is you. If you turn your head, the room you’re sitting in looks like it’s turning the other way. But our brain compensates for that; it “knows” it’s moving, so you perceive the room as motionless. But this works the other way, too: You can make the brain think something is moving even when it’s not. That’s the principle behind this wonderful optical illusion video created by brusspup: Isn’t that great? Your brain will swear those drawings are moving, even when you can see they are not. Even the cat was fooled! This video looks fantastically complicated, but the way it works is actually pretty simple. Basically, it’s fooling your brain into ignoring the thing that is moving, and making it look like the motionless thing is what’s doing the moving. © 2013 The Slate Group, LLC.

Keyword: Vision
Link ID: 19040 - Posted: 12.17.2013

By ALAN SCHWARZ After more than 50 years leading the fight to legitimize attention deficit hyperactivity disorder, Keith Conners could be celebrating. Severely hyperactive and impulsive children, once shunned as bad seeds, are now recognized as having a real neurological problem. Doctors and parents have largely accepted drugs like Adderall and Concerta to temper the traits of classic A.D.H.D., helping youngsters succeed in school and beyond. But Dr. Conners did not feel triumphant this fall as he addressed a group of fellow A.D.H.D. specialists in Washington. He noted that recent data from the Centers for Disease Control and Prevention show that the diagnosis had been made in 15 percent of high school-age children, and that the number of children on medication for the disorder had soared to 3.5 million from 600,000 in 1990. He questioned the rising rates of diagnosis and called them “a national disaster of dangerous proportions.” “The numbers make it look like an epidemic. Well, it’s not. It’s preposterous,” Dr. Conners, a psychologist and professor emeritus at Duke University, said in a subsequent interview. “This is a concoction to justify the giving out of medication at unprecedented and unjustifiable levels.” The rise of A.D.H.D. diagnoses and prescriptions for stimulants over the years coincided with a remarkably successful two-decade campaign by pharmaceutical companies to publicize the syndrome and promote the pills to doctors, educators and parents. With the children’s market booming, the industry is now employing similar marketing techniques as it focuses on adult A.D.H.D., which could become even more profitable. Few dispute that classic A.D.H.D., historically estimated to affect 5 percent of children, is a legitimate disability that impedes success at school, work and personal life. Medication often assuages the severe impulsiveness and inability to concentrate, allowing a person’s underlying drive and intelligence to emerge. © 2013 The New York Times Company

Keyword: ADHD; Drug Abuse
Link ID: 19039 - Posted: 12.16.2013

By John Chipman, CBC News Andrew Solomon is not your typical depressive, if such a thing exists. Most people struggling with clinical depression do not like to talk about it. Depression is usually suffered in silence, because of the stigma that still clings to it. Many people still see depression as a sign of weakness, or believe that if you just cheered up or had a better attitude you'd feel so much better. Solomon has heard the wrong-headed chatter most of his life. But rather than shy away, the journalist and best-selling author wrote a book about it, detailing his own struggles with depression. It’s called The Noonday Demon: An Atlas of Depression. And he has become a vocal advocate, calling for more progressive attitudes about the disease so that people suffering from it can step out of the shadows and feel comfortable getting the help they need to survive, and to thrive. So it was with some shock and dismay that Solomon learned about Ellen Richardson, a Canadian woman turned back at the U.S. border last month because she was hospitalized last year for her depression. Richardson was told she could only enter the U.S. if a doctor — not her own, but one from a shortlist of others whom she had never met — signed a document vouching for her. She would also have to pay a fee of $500. U.S. border guards are allowed to bar anyone they deem a threat to themselves, to other Americans, or their property. They have access to police records — including even uneventful encounters with officers — but medical records are supposed to be held in the strictest confidence. © CBC 2013

Keyword: Depression; Emotions
Link ID: 19038 - Posted: 12.16.2013

Bats can understand the emotional state of other bats from the intonations of their calls, a new study suggests. In the lab, researchers observed greater false vampire bats (Megaderma lyra, pictured) that had been trained to wait for food on a perch. In some tests, they played “aggression calls” over a speaker, typically made by a bat defending its place on a perch from an approaching bat. In other trials, the researchers played “appeasement calls” often made by a bat approaching one already ensconced on a perch and thus seeking to share its space. (Bats were tested individually, and the use of recorded calls ensured that the bats were responding to the content of the call and not visual cues from another bat.) In all tests, the scientists played a call once every 20 seconds until the bats began to ignore the call (by not turning toward the speaker), and then they played a slightly different version of the same call—one that was either more urgent (with shorter, more closely spaced syllables) or less urgent. The novel aggression calls always caused a bat to turn toward the speaker, but the novel appeasement calls only drew a response when they became more urgent, the researchers report online today in Frontiers of Zoology. The failure of a bat to react to weakening appeasement calls suggests that the bats can interpret the emotional content of the calls—a sign that such perception might exist more widely in mammals than previously thought. © 2013 American Association for the Advancement of Science.

Keyword: Hearing; Emotions
Link ID: 19037 - Posted: 12.16.2013

Associated Press The U.S. Navy plans to increase sonar testing over the next five years, even as research it funded reveals worrying signs that the loud underwater noise could disturb whales and dolphins. Reported mass strandings of whale species have increased worldwide since the military started using sonar half a century ago. Scientists think the sounds scare animals into shallow waters where they can become disoriented and wash ashore, but technology capable of close monitoring has emerged only in the past decade. Aside from strandings, biologists are concerned marine mammals could suffer prolonged stress from changes in diving, feeding and communication. Two studies off the Southern California coast found certain endangered blue whales and beaked whales stopped feeding and fled from recordings of sounds similar to military sonar. Beaked whales are highly sensitive to sound and account for the majority of beachings near military exercises. Scientists, however, were surprised by the reaction of blue whales - the world's largest animal - long thought to be immune to the high-pitched sounds. It's unclear how the change in behavior would affect the overall population, estimated at between 5,000 and 12,000 animals. The studies involved only a small group of tagged whales, and noise levels were less intense than what's used by the Navy. Shy species - such as the Cuvier's beaked whale, which can dive 3,000 feet below the surface - have taken years to find and monitor. "This is a warning flag and deserves more research," said Stanford University biologist Jeremy Goldbogen, who led the blue whale study published this summer in the journal Proceedings of the Royal Society B. © 2013 Hearst Communications, Inc.

Keyword: Hearing; Animal Migration
Link ID: 19036 - Posted: 12.16.2013

by Bethany Brookshire “You are what you eat.” We’ve all heard that one. What we eat can affect our growth, life span and whether we develop disease. These days, we know that we also are what our mother eats. Or rather, what our mothers ate while we were in the womb. But are we also what our father eats? A new study shows that in mice, a dietary deficiency in dad can be a big downer for baby. The dietary staple in the study was folic acid, or folate. Folate is one of the B vitamins and is found in dark leafy greens (eat your kale!) and has even been added to some foods like cereals. It is particularly essential to get in the diet because we cannot synthesize it on our own. And it plays roles in DNA repair and DNA synthesis, as well as methylation of DNA. It’s particularly important during development. Without adequate folate, developing fetuses are prone to neural tube disorders, such as spina bifida. Some of the neural tube disorders caused by folate deficiency could result from breaks in the DNA itself. But folic acid is also important in the epigenome. Epigenetics is a mechanism that allows cells to change how genes are used without changing the genes themselves. Instead of altering the DNA itself, epigenetic alterations put chemical “marks” or “notes” —methyl or acetyl groups — on the DNA and the proteins associated with it. The marks can either make a gene more accessible (acetylation) or less accessible (methylation), making it more or less likely to be made into a protein. This means that each cell type can have a different epigenome, allowing a neuron to function differently than a muscle cell, even though they contain the same DNA. Folate affects DNA synthesis, but it can also affect DNA methylation. In fact, DNA methylation requires the presence of folate. So low folate could affect whether genes are turned off or on and by how much. In a developing fetus, that could contribute to developmental problems. © Society for Science & the Public 2000 - 2013.

Keyword: Epigenetics; Development of the Brain
Link ID: 19035 - Posted: 12.14.2013

Oliver Burkeman As we stumble again into the season of overindulgence – that sacred time of year when wine, carbs and sofas replace brisk walks for all but the most virtuous – a headline in the (excellent) new online science magazine Nautilus catches my eye: "What If Obesity Is Nobody's Fault?" The article describes new research on mice: a genetic alteration, it appears, can make them obese, despite eating no more than others. "Many of us unfortunately have had an attitude towards obese people [as] having a lack of willpower or self-control," one Harvard researcher is quoted as saying. "It's clearly something beyond that." No doubt. But that headline embodies an assumption that's rarely questioned. Suppose, hypothetically, obesity were solely a matter of willpower: laying off the crisps, exercising and generally bucking your ideas up. What makes us so certain that obesity would be the fault of the obese even then? This sounds like the worst kind of bleeding-heart liberalism, a condition from which I probably suffer (I blame my genes). But it's a real philosophical puzzle, with implications reaching far beyond obesity to laziness in all contexts, from politicians' obsession with "hardworking families" to the way people beat themselves up for not following through on their plans. We don't blame people for most physical limitations (if you broke your leg, it wouldn't be a moral failing to cancel your skydiving trip), nor for many other impediments: it's hardly your fault if you're born into educational or economic disadvantage. Yet almost everyone treats laziness and weakness of will as exceptions. If you can't be bothered to try, you've only yourself to blame. It's a rule some apply most harshly to themselves, mounting epic campaigns of self-chastisement for procrastinating, failing to exercise and so on. © 2013 Guardian News and Media Limited

Keyword: Attention; Consciousness
Link ID: 19034 - Posted: 12.14.2013

A study in mice shows how a breakdown of the brain’s blood vessels may amplify or cause problems associated with Alzheimer’s disease. The results published in Nature Communications suggest that blood vessel cells called pericytes may provide novel targets for treatments and diagnoses. “This study helps show how the brain’s vascular system may contribute to the development of Alzheimer’s disease,” said study leader Berislav V. Zlokovic, M.D. Ph.D., director of the Zilkha Neurogenetic Institute at the Keck School of Medicine of the University of Southern California, Los Angeles. The study was co-funded by the National Institute of Neurological Diseases and Stroke (NINDS) and the National Institute on Aging (NIA), parts of the National Institutes of Health. Alzheimer’s disease is the leading cause of dementia. It is an age-related disease that gradually erodes a person’s memory, thinking, and ability to perform everyday tasks. Brains from Alzheimer’s patients typically have abnormally high levels of plaques made up of accumulations of beta-amyloid protein next to brain cells, tau protein that clumps together to form neurofibrillary tangles inside neurons, and extensive neuron loss. Vascular dementias, the second leading cause of dementia, are a diverse group of brain disorders caused by a range of blood vessel problems. Brains from Alzheimer’s patients often show evidence of vascular disease, including ischemic stroke, small hemorrhages, and diffuse white matter disease, plus a buildup of beta-amyloid protein in vessel walls. Furthermore, previous studies suggest that APOE4, a genetic risk factor for Alzheimer’s disease, is linked to brain blood vessel health and integrity.

Keyword: Alzheimers
Link ID: 19033 - Posted: 12.14.2013

Skepticism about repressed traumatic memories has increased over time, but new research shows that psychology researchers and practitioners still tend to hold different beliefs about whether such memories occur and whether they can be accurately retrieved. The findings are published in Psychological Science, a journal of the Association for Psychological Science. “Whether repressed memories are accurate or not, and whether they should be pursued by therapists, or not, is probably the single most practically important topic in clinical psychology since the days of Freud and the hypnotists who came before him,” says researcher Lawrence Patihis of the University of California, Irvine. According to Patihis, the new findings suggest that there remains a “serious split in the field of psychology in beliefs about how memory works.” Controversy surrounding repressed memory – sometimes referred to as the “memory wars” – came to a head in the 1990s. While some believed that traumatic memories could be repressed for years only to be recovered later in therapy, others questioned the concept, noting that lack of scientific evidence in support of repressed memory. Spurred by impressions that both researchers and clinicians believed the debate had been resolved, Patihis and colleagues wanted to investigate whether and how beliefs about memory may have changed since the 1990s. To find out, the researchers recruited practicing clinicians and psychotherapists, research psychologists, and alternative therapists to complete an online survey. © Association for Psychological Science

Keyword: Learning & Memory; Emotions
Link ID: 19032 - Posted: 12.14.2013

By ROBERT PEAR WASHINGTON — Psychiatrists are significantly less likely than doctors in other specialties to accept insurance, researchers say in a new study, complicating the push to increase access to mental health care. The study, published Wednesday in the journal JAMA Psychiatry, found that 55 percent of psychiatrists accepted private insurance, compared with 89 percent of other doctors. Likewise, the study said, 55 percent of psychiatrists accept patients covered by Medicare, against 86 percent of other doctors. And 43 percent of psychiatrists accept Medicaid, which provides coverage for low-income people, while 73 percent of other doctors do. The lead author of the study, Dr. Tara F. Bishop of Weill Cornell Medical College in New York, said: “In the wake of the school killings in Newtown, Conn., and other recent mass shootings, the need for increased mental health services is now recognized. But unless patients have deep pockets, they may have a hard time finding a psychiatrist who will treat them.” Mental health care is one of 10 types of “essential health benefits” that must be provided by insurers under the new health care law. A federal rule issued last month requires insurers to cover care for mental health and addiction on the same terms as treatments for physical illnesses, without charging higher co-payments or deductibles or imposing stricter limits on services. Starting next year, Medicare will end a discriminatory policy that for decades has required people to pay a larger share of the bill for mental health care than for other outpatient services. However, the study suggests that expanding coverage may not by itself guarantee access to psychiatrists. “Even if you have good insurance that covers mental health care, you may still have a problem if there’s no doctor who accepts your insurance,” Dr. Bishop said. © 2013 The New York Times Company

Keyword: Depression; Schizophrenia
Link ID: 19031 - Posted: 12.12.2013

Smoking tobacco or marijuana, taking prescription painkillers, or using illegal drugs during pregnancy is associated with double or even triple the risk of stillbirth, according to research funded by the National Institutes of Health. Researchers based their findings on measurements of the chemical byproducts of nicotine in maternal blood samples; and cannabis, prescription painkillers and other drugs in umbilical cords. Taking direct measurements provided more precise information than did previous studies of stillbirth and substance use that relied only on women’s self-reporting. The study findings appear in the journal Obstetrics & Gynecology. “Smoking is a known risk factor for stillbirth, but this analysis gives us a much clearer picture of the risks than before,” said senior author Uma M. Reddy, M.D., MPH, of the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), the NIH institute that supported the study. “Additionally, results from the latest findings also showed that likely exposure to secondhand smoke can elevate the risk of stillbirth.” Dr. Reddy added, “With the legalization of marijuana in some states, it is especially important for pregnant women and health care providers to be aware that cannabis use can increase stillbirth risk.” The study enrolled women between March 2006 and September 2008 in five geographically defined areas delivering at 59 hospitals participating in the Stillbirth Collaborative Research Network External Web Site Policy. Women who experienced a stillbirth and those who gave birth to a live infant participated in the study. The researchers tested blood samples at delivery from the two groups of women and the umbilical cords from their deliveries to measure the exposure to the fetus. They also asked participants to self-report smoking and drug use during pregnancy.

Keyword: Development of the Brain; Drug Abuse
Link ID: 19030 - Posted: 12.12.2013

by Rowan Hooper BIOENGINEERS dream of growing spare parts for our worn-out or diseased bodies. They have already succeeded with some tissues, but one has always eluded them: the brain. Now a team in Sweden has taken the first step towards this ultimate goal. Growing artificial body parts in the lab starts with a scaffold. This acts as a template on which to grow cells from the patient's body. This has been successfully used to grow lymph nodes, heart cells and voice boxes from a person's stem cells. Bioengineers have even grown and transplanted an artificial kidney in a rat. Growing nerve tissue in the lab is much more difficult, though. In the brain, new neural cells grow in a complex and specialised matrix of proteins. This matrix is so important that damaged nerve cells don't regenerate without it. But its complexity is difficult to reproduce. To try to get round this problem, Paolo Macchiarini and Silvia Baiguera at the Karolinska Institute in Stockholm, Sweden, and colleagues combined a scaffold made from gelatin with a tiny amount of rat brain tissue that had already had its cells removed. This "decellularised" tissue, they hoped, would provide enough of the crucial biochemical cues to enable seeded cells to develop as they would in the brain. When the team added mesenchymal stem cells – taken from another rat's bone marrow – to the mix, they found evidence that the stem cells had started to develop into neural cells (Biomaterials, doi.org/qfh). The method has the advantage of combining the benefits of natural tissue with the mechanical properties of an artificial matrix, says Alex Seifalian, a regenerative medicine specialist at University College London, who wasn't involved in the study. © Copyright Reed Business Information Ltd.

Keyword: Development of the Brain
Link ID: 19029 - Posted: 12.12.2013

By Janelle Weaver Children with a large vocabulary experience more success at school and in the workplace. How much parents talk to their children plays a major role, but new research shows that it is not just the quantity but also the quality of parental input that matters. Helpful gestures and meaningful glances may allow kids to grasp concepts more easily than they otherwise would. In a study published in June in the Proceedings of the National Academy of Sciences USA, Erica Cartmill of the University of Chicago and her collaborators videotaped parents in their homes as they read books and played games with their 14- or 18-month-old children. The researchers created hundreds of 40-second muted video clips of these interactions. Another set of study participants watched the videos and used clues from the scenes to guess which nouns the parents were saying at various points in the sequences. The researchers used the accuracy of these guesses to rate how well a parent used nonverbal cues, such as gesturing toward and looking at objects, to clarify a word's meaning. Cartmill and her team found that the quality of parents' nonverbal signaling predicted the size of their children's vocabulary three years later. Surprisingly, socioeconomic status did not play a role in the quality of the parents' nonverbal signaling. This result suggests that the well-known differences in children's vocabulary size across income levels are likely the result of how much parents talk to their children, which is known to differ by income, rather than how much nonverbal help they offer during those interactions. © 2013 Scientific American

Keyword: Language; Development of the Brain
Link ID: 19028 - Posted: 12.12.2013

Ian Sample, science correspondent Differences in children's exam results at secondary school owe more to genetics than teachers, schools or the family environment, according to a study published yesterday. The research drew on the exam scores of more than 11,000 16-year-olds who sat GCSEs at the end of their secondary school education. In the compulsory core subjects of English, maths and science, genetics accounted for on average 58% of the differences in scores that children achieved. Grades in the sciences, such as physics, biology and chemistry, were more heritable than those in humanities subjects, such as art and music, at 58% and 42% respectively. The findings do not mean that children's performance at school is determined by their genes, or that schools and the child's environment have no influence. The overall effect of a child's environment – including their home and school life – accounted for 36% of the variation seen in students' exam scores across all subjects, the study found. "The question we are asking is why do children differ in their GCSE scores? People immediately think it's schools. But if schools accounted for all the variance, then children in one classroom would all be the same," said Robert Plomin, an expert in behavioural genetics who led the study at King's College London. To tease out the genetic contribution to children's school grades, the researchers studied GCSE scores of identical twins (who share 100% of their genes) and non-identical twins (who share on average half of the genes that normally vary between people). Both groups share their environments to a similar extent. © 2013 Guardian News and Media Limited

Keyword: Intelligence; Genes & Behavior
Link ID: 19027 - Posted: 12.12.2013

By Sanaz Majd MD Scientific American presents House Call Doctor by Quick & Dirty Tips. Scientific American and Quick & Dirty Tips are both Macmillan companies. Have you been told by your spouse that you “fidget” in the middle of the night? Or have you noticed your legs or feet may have a mind of their own when you’re trying to fall asleep? Do you have an urge to move your legs a lot at bedtime? You may very well be one of the many people who remain undiagnosed with the condition called Restless Legs Syndrome, or RLS. For those who have never experienced RLS, it may seem like a very odd and peculiar phenomenon. But if you’ve ever had these symptoms, you may be surprised to learn that this is an actual medical condition. Maybe you’ve already mentioned it to your doctor, or maybe you never realized it was real until now. Either way, let’s find out more about Restless Legs Syndrome and how it’s treated. What Is RLS? I’ve actually discussed RLS in a previous episode on insomnia, and you may want to revisit that episode before moving on to this one. But in a nutshell, here are the symptoms that up to 10% of the American population are estimated to be suffering from: © 2013 Scientific American

Keyword: Sleep
Link ID: 19026 - Posted: 12.12.2013

By MAGGIE KOERTH-BAKER More than a decade ago, a 43-year-old woman went to a surgeon for a hysterectomy. She was put under, and everything seemed to be going according to plan, until, for a horrible interval, her anesthesia stopped working. She couldn’t open her eyes or move her fingers. She tried to breathe, but even that most basic reflex didn’t seem to work; a tube was lodged in her throat. She was awake and aware on the operating table, but frozen and unable to tell anyone what was happening. Studies of anesthesia awareness are full of such horror stories, because administering anesthesia is a tightrope walk. Too much can kill. But too little can leave a patient aware of the procedure and unable to communicate that awareness. For every 1,000 people who undergo general anesthesia, there will be one or two who are not as unconscious as they seem — people who remember their doctors talking, and who are aware of the surgeon’s knife, even while their bodies remain catatonic and passive. For the unlucky 0.13 percent for whom anesthesia goes awry, there’s not really a good preventive. That’s because successful anesthetization requires complete unconsciousness, and consciousness isn’t something we can measure. There are tools that anesthesiologists use to get a pretty good idea of how well their drugs are working, but these systems are imperfect. For most patients receiving inhaled anesthesia, they’re no better at spotting awareness than dosing metrics developed half a century ago, says George Mashour, a professor of anesthesiology at the University of Michigan Medical School. There are two intertwined mysteries at work, Mashour told me: First, we don’t totally understand how anesthetics work, at least not on a neurological basis. Second, we really don’t understand consciousness — how the brain creates it, or even what, exactly, it is. © 2013 The New York Times Company

Keyword: Consciousness; Sleep
Link ID: 19025 - Posted: 12.11.2013

By Graham Lawton Patricia Churchland, a neurophilosopher at the University of California at San Diego, says our hopes, loves and very existence are just elaborate functions of a complicated mass of grey tissue. Accepting that can be hard, but what we know should inspire us, not scare us. Her most recent book is Touching a Nerve: The Self as Brain. Graham Lawton: You compare revelations in neuroscience with the discoveries that the Earth goes around the sun and that the heart is a pump. What do you think these ideas have in common? Patricia Churchland: They challenge a whole framework of assumptions about the way things are. For Christians, it was very important that the Earth was at the center of the universe. Similarly, many people believed that the heart was somehow what made us human. And it turned out it was just a pump made of meat. I think the same is true about realizing that when we're conscious, when we make decisions, when we go to sleep, when we get angry, when we're fearful, these are just functions of the physical brain. Coming to terms with the neural basis of who we are can be very unnerving. It has been called "neuroexistentialism," which really captures the essence of it. We're not in the habit of thinking about ourselves that way. GL: Why is it so difficult for us to see the reality of what we actually are? PC: Part of the answer has to do with the evolution of nervous systems. Is there any reason for a brain to know about itself? We can get along without knowing, just as we can get along without knowing that the liver is in there filtering out toxins. The wonderful thing, of course, is that science allows us to know. © 2013 The Slate Group, LLC.

Keyword: Consciousness
Link ID: 19024 - Posted: 12.11.2013

by Chelsea Whyte For chameleons, war paint isn't just an accessory, it is a battle flag. The brightness of the colours these lizards display and how rapidly they change are good indicators of which animal will win in a fight. Chameleons are famous for changing colour to hide from predators by blending into their surroundings, but they also use colour for social communication. One of the most diversely coloured species is the veiled chameleon (Chamaeleo calyptratus), which lives in parts of Saudi Arabia and Yemen. "At their brightest, they have vertical yellow stripes, blue-green bellies, black speckles that provide contrast and make their stripes stand out, and orange around the corner of their mouths," says Russell Ligon, a behavioural ecologist at Arizona State University in Tempe. To see if individual variations in these colours and patterns influenced the outcome of a fight, Ligon and his colleague Kevin McGraw staged a round-robin tournament in which 10 male veiled chameleons were pitted against each other. Using a high-speed camera, they were able to capture the brightness and colour changes from 28 points on each animal, taking into account how the colours would look to a chameleon's eye – which sees both visible and ultraviolet light. They found that males with the brightest side stripes were more likely to instigate a fight, whereas those with brighter heads that changed colour most rapidly were more likely to win. This suggests that different colours and patterns may signal different aspects of competitive behaviour – how motivated the chameleon is versus its strength. © Copyright Reed Business Information Ltd.

Keyword: Aggression; Sexual Behavior
Link ID: 19023 - Posted: 12.11.2013

By Ben Thomas 2013’s Nobel prize in Physiology or Medicine honors three researchers in particular – but what it really honors is thirty-plus years of work not only from them, but also from their labs, their graduate students and their collaborators. Winners James Rothman, Randy Schekman and Thomas Südhof all helped assemble our current picture of the cellular machinery that enables neurotransmitter chemicals to travel from one nerve cell to the next. And as all three of these researchers agree, that process of understanding didn’t catalyze until the right lines of research, powered by the right tools, happened to converge at the right time. Long before that convergence, though, these three scientists began by seeking the answers to three different questions – none of which seemed to have anything to do with the others. When James Rothman started out as a researcher at Harvard in 1978, his goal was to find out exactly how vesicle transmission worked. Vesicles – Latin for “little vessels” – are the microscopic capsules that carry neurotransmitter molecules like serotonin and dopamine from one brain cell to another. By the late 1960s, the old-guard biochemist George Palade, along with other researchers, had already deduced that synaptic vesicles are necessary for neurotransmission – but the questions of which proteins guided these tiny vessels on their journey, and how they docked with receiving neurons, remained mysterious. Yale University's James Rothman set out to break down the process of vesicle transmission, chemical-by-chemical, reaction-by-reaction. Courtesy of Yale University. In other words, although researchers had established the existence of this vesicle transmission process, no one knew exactly what made it work, or how. © 2013 Scientific American

Keyword: Miscellaneous
Link ID: 19022 - Posted: 12.11.2013

by Bethany Brookshire When neurons throughout the brain and body send messages, they release chemical signals. These chemicals, neurotransmitters, pass into the spaces between neurons, or synapses, binding to receptors to send a signal along. When they are not in use, neurotransmitters are stored within the cell in tiny bubbles called vesicles. During signaling, these vesicles head to the membrane of the neuron, where they dump neurotransmitter into the synapse. And after delivering their cargo, most vesicles disappear. But more vesicles keep forming, filling with neurotransmitters so neurons can keep sending signals. What goes up must come down. When vesicles go out, they must come back. But how fast to the vesicles re-appear? Must faster, it turns out, than we first thought. Neurotransmission happens fast. An electrical signal comes down a neuron in your brain and triggers vesicles to move to the cell membrane. When the vesicles merge into the membrane and release their chemical cargo, the neurotransmitters float across the open synapse to the next neuron. This happens every time the neuron “fires.” This needs to happen very quickly, as neurons often fire at 100 hertz, or 100 times per second. Some neurons perform a “kiss-and-run,” opening up a temporary pore in the membrane, releasing a little bit of neurotransmitter and darting away again. Other vesicles need to merge with the synapse entirely. With the assistance of docking proteins, these vesicles fuse with the membrane of the neuron to release the neurotransmitters, a process called exocytosis. © Society for Science & the Public 2000 - 2013.

Keyword: Miscellaneous
Link ID: 19021 - Posted: 12.11.2013