Chapter 16. None
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By Kevin Hartnett You may have seen that deliberately annoying “View of the World from Ninth Avenue” map featured on the cover of the New Yorker a while back. It shows the distorted way geography appears to a Manhattanite: 9th and 10th avenues are the center of the world, New Jersey appears, barely, and everywhere else is just a blip if it registers at all. As it turns out, a similar kind of map exists for the human body — with at least some basis in neuroscience. In August I wrote a story for Ideas on the rise of face transplants and spoke to Michael Sims, author of the book, “Adam’s Navel: A Natural and Cultural History of the Human Form.” During our conversation Sims mentioned an odd diagram published in 1951 by a neurosurgeon named Wilder Penfield. The diagram is known as “Homunculus” (a name taken from a weird and longstanding art form that depicts small human beings); it shows the human body scaled according to the amount of brain tissue dedicated to each part, and arranged according to the locations in the brain that control them. In the diagram, the eyes, lips, nose, and tongue appear grotesquely large, indicating that we devote an outsized amount of brain tissue to operating and receiving sensation from these parts of the body. (Sims’s point was that we devote a lot of processing power to the face, and for that reason find it biologically disorienting that faces could be changeable.) The hand is quite large, too, while the toes, legs, trunks, shoulders, and arms are tiny, the equivalents of Kansas City and Russia on the New Yorker map. “Homunculus” seems like the kind of thing that would have long since been superseded by modern brain science, but it actually continues to have a surprising amount of authority, and often appears in neuroscience textbooks.
Keyword: Pain & Touch
Link ID: 20158 - Posted: 10.04.2014
By John Bohannon The victim peers across the courtroom, points at a man sitting next to a defense lawyer, and confidently says, "That's him!" Such moments have a powerful sway on jurors who decide the fate of thousands of people every day in criminal cases. But how reliable is eyewitness testimony? A new report concludes that the use of eyewitness accounts need tighter control, and among its recommendations is a call for a more scientific approach to how eyewitnesses identify suspects during the classic police lineup. For decades, researchers have been trying to nail down what influences eyewitness testimony and how much confidence to place in it. After a year of sifting through the scientific evidence, a committee of psychologists and criminologists organized by the U.S. National Research Council (NRC) has now gingerly weighed in. "This is a serious issue with major implications for our justice system," says committee member Elizabeth Phelps, a psychologist at New York University in New York City. Their 2 October report, Identifying the Culprit: Assessing Eyewitness Identification, is likely to change the way that criminal cases are prosecuted, says Elizabeth Loftus, a psychologist at the University of California, Irvine, who was an external reviewer of the report. As Loftus puts it, "just because someone says something confidently doesn't mean it's true." Jurors can't help but find an eyewitness’s confidence compelling, even though experiments have shown that a person's confidence in their own memory is sometimes undiminished even in the face of evidence that their memory of an event is false. © 2014 American Association for the Advancement of Science.
Keyword: Learning & Memory
Link ID: 20157 - Posted: 10.04.2014
Carl Zimmer As much as we may try to deny it, Earth’s cycle of day and night rules our lives. When the sun sets, the encroaching darkness sets off a chain of molecular events spreading from our eyes to our pineal gland, which oozes a hormone called melatonin into the brain. When the melatonin latches onto neurons, it alters their electrical rhythm, nudging the brain into the realm of sleep. At dawn, sunlight snuffs out the melatonin, forcing the brain back to its wakeful pattern again. We fight these cycles each time we stay up late reading our smartphones, suppressing our nightly dose of melatonin and waking up grumpy the next day. We fly across continents as if we could instantly reset our inner clocks. But our melatonin-driven sleep cycle lags behind, leaving us drowsy in the middle of the day. Scientists have long wondered how this powerful cycle got its start. A new study on melatonin hints that it evolved some 700 million years ago. The authors of the study propose that our nightly slumbers evolved from the rise and fall of our tiny oceangoing ancestors, as they swam up to the surface of the sea at twilight and then sank in a sleepy fall through the night. To explore the evolution of sleep, scientists at the European Molecular Biology Laboratory in Germany study the activity of genes involved in making melatonin and other sleep-related molecules. Over the past few years, they’ve compared the activity of these genes in vertebrates like us with their activity in a distantly related invertebrate — a marine worm called Platynereis dumerilii. The scientists studied the worms at an early stage, when they were ball-shaped 2-day-old larvae. The ocean swarms with juvenile animals like these. Many of them spend their nights near the ocean surface, feeding on algae and other bits of food. Then they spend the day at lower depths, where they can hide from predators and the sun’s ultraviolet rays. © 2014 The New York Times Company
By CATHERINE SAINT LOUIS Driven by a handful of reports of poliolike symptoms in children, federal health officials have asked the nation’s physicians to report cases of children with limb weakness or paralysis along with specific spinal-cord abnormalities on a magnetic resonance imaging test. As a respiratory illness known as enterovirus 68 is sickening thousands of children from coast to coast, officials are trying to figure out if the weakness could be linked to the virus. The emergence of several cases of limb weakness among children in Colorado put doctors on alert in recent months. The Centers for Disease Control and Prevention issued an advisory on Friday, and this week, other cases of unexplained muscle weakness or paralysis came to light in Michigan, Missouri and Massachusetts. The C.D.C. is investigating the cases of 10 children hospitalized at Children’s Hospital Colorado with unexplained arm or leg weakness since Aug. 9. Some of the children, who range in age from 1 to 18, also developed symptoms like facial drooping, double vision, or difficulty swallowing or talking. Four of them tested positive for enterovirus 68, also known as enterovirus D68, which has recently caused severe respiratory illness in children in 41 states and the District of Columbia. One tested positive for rhinovirus, which can cause the common cold. Two tested negative. Two patients’ specimens are still being processed; another was never tested. It is unclear whether the muscle weakness is connected to the viral outbreak. “It’s one possibility we are looking at, but certainly not the only possibility,” said Mark Pallansch, director of the C.D.C.’s division of viral diseases. © 2014 The New York Times Company
Keyword: Movement Disorders
Link ID: 20150 - Posted: 10.02.2014
Have you ever wrongly suspected that other people are out to harm you? Have you been convinced that you’re far more talented and special than you really are? Do you sometimes hear things that aren’t actually there? These experiences – paranoia, grandiosity and hallucinations in the technical jargon – are more common among the general population than is usually assumed. But are people who are susceptible simply “made that way”? Are they genetically predisposed, in other words, or have their life experiences made them more vulnerable to these things? It’s an old debate: which is more important, nature or nurture? Scientists nowadays tend to agree that human psychology is a product of a complex interaction between genes and experience – which is all very well, but where does the balance lie? Scientists (including one of the authors of this blog) recently conducted the first ever study among the general population of the relative contributions of genes and environment to the experience of paranoia, grandiosity and hallucinations. How did we go about the research? First, it is important to be clear about the kinds of experience we measured. By paranoia, we mean the unfounded or excessive fear that other people are out to harm us. Grandiosity denotes an unrealistic conviction of one’s abilities and talents. Hallucinations are sensory experiences (hearing voices, for instance) that aren’t caused by external events. Led by Dr Angelica Ronald at Birkbeck, University of London, the team analysed data on almost 5,000 pairs of 16-year-old twins. This is the classical twin design, a standard method for gauging the relative influence of genes and environment. Looking simply at family traits isn’t sufficient: although family members share many genes, they also tend to share many of the same experiences. This is why studies involving twins are so useful. © 2014 Guardian News and Media Limited
Link ID: 20147 - Posted: 10.02.2014
by Jason M. Breslow As the NFL nears an end to its long-running legal battle over concussions, new data from the nation’s largest brain bank focused on traumatic brain injury has found evidence of a degenerative brain disease in 76 of the 79 former players it’s examined. The findings represent a more than twofold increase in the number of cases of chronic traumatic encephalopathy, or CTE, that have been reported by the Department of Veterans Affairs’ brain repository in Bedford, Mass. Researchers there have now examined the brain tissue of 128 football players who, before their deaths, played the game professionally, semi-professionally, in college or in high school. Of that sample, 101 players, or just under 80 percent, tested positive for CTE. To be sure, players represented in the data represent a skewed population. CTE can only be definitively identified posthumously, and many of the players who have donated their brains for research suspected that they may have had the disease while still alive. For example, former Chicago Bears star Dave Duerson committed suicide in 2011 by shooting himself in the chest, reportedly to preserve his brain for examination. Nonetheless, Dr. Ann McKee, the director of the brain bank, believes the findings suggest a clear link between football and traumatic brain injury. “Obviously this high percentage of living individuals is not suffering from CTE,” said McKee, a neuropathologist who directs the brain bank as part of a collaboration between the VA and Boston University’s CTE Center. But “playing football, and the higher the level you play football and the longer you play football, the higher your risk.” ©1995-2014 WGBH Educational Foundation
Keyword: Brain Injury/Concussion
Link ID: 20146 - Posted: 10.01.2014
By Sarah C. P. Williams A wind turbine, a roaring crowd at a football game, a jet engine running full throttle: Each of these things produces sound waves that are well below the frequencies humans can hear. But just because you can’t hear the low-frequency components of these sounds doesn’t mean they have no effect on your ears. Listening to just 90 seconds of low-frequency sound can change the way your inner ear works for minutes after the noise ends, a new study shows. “Low-frequency sound exposure has long been thought to be innocuous, and this study suggests that it’s not,” says audiology researcher Jeffery Lichtenhan of the Washington University School of Medicine in in St. Louis, who was not involved in the new work. Humans can generally sense sounds at frequencies between 20 and 20,000 cycles per second, or hertz (Hz)—although this range shrinks as a person ages. Prolonged exposure to loud noises within the audible range have long been known to cause hearing loss over time. But establishing the effect of sounds with frequencies under about 250 Hz has been harder. Even though they’re above the lower limit of 20 Hz, these low-frequency sounds tend to be either inaudible or barely audible, and people don’t always know when they’re exposed to them. For the new study, neurobiologist Markus Drexl and colleagues at the Ludwig Maximilian University in Munich, Germany, asked 21 volunteers with normal hearing to sit inside soundproof booths and then played a 30-Hz sound for 90 seconds. The deep, vibrating noise, Drexl says, is about what you might hear “if you open your car windows while you’re driving fast down a highway.” Then, they used probes to record the natural activity of the ear after the noise ended, taking advantage of a phenomenon dubbed spontaneous otoacoustic emissions (SOAEs) in which the healthy human ear itself emits faint whistling sounds. © 2014 American Association for the Advancement of Science
Link ID: 20144 - Posted: 10.01.2014
It's not just humans who want the latest gadget. Wild chimpanzees that see a friend making and using a nifty new kind of tool are likely to make one for themselves, scientists report. "Our study adds new evidence supporting the hypothesis that some of the behavioural diversity seen in wild chimpanzees is the result of social transmission and can therefore be interpreted as cultural," an international research team writes today in the journal PLOS ONE. The findings suggest that the ability of individuals to learn from one another originated long ago in a common ancestor of chimpanzees and humans, the researchers add. "This study tells us that chimpanzee culture changes over time, little by little, by building on previous knowledge found within the community," said Thibaud Gruber, a co-author of the study, in a statement. "This is probably how our early ancestors' cultures also changed over time." Scientists already knew that chimpanzees in different groups have certain behaviours unique to their group, such as using a particular kind of tool. They suspected that wild chimpanzees learn those behaviours from other chimpanzees within their group, as scientists have observed in captive chimps. But they could never be sure. The new study documents the spread of two new behaviours among chimpanzees living in Uganda's Budongo Forest. It shows that chimps learned one of them — the making and use of a new tool called a moss sponge — by observing other chimps who had already adopted the behaviour. Chimps dip the tool in water and then put it in their mouth to drink. © CBC 2014
Link ID: 20141 - Posted: 10.01.2014
|By Tanya Lewis and LiveScience Dolphins can now add magnetic sense to their already impressive resume of abilities, new research suggests. When researchers presented the brainy cetaceans with magnetized or unmagnetized objects, the dolphins swam more quickly toward the magnets, the new study found. The animals may use their magnetic sense to navigate based on the Earth's magnetic field, the researchers said. A number of different animals are thought to possess this magnetic sense, called "magnetoreception," including turtles, pigeons, rodents, insects, bats and even deer (which are related to dolphins), said Dorothee Kremers, an animal behavior expert at the University of Rennes, in France, and co-author of the study published today (Sept. 29) in the journal Naturwissenschaften. "Inside the ocean, the magnetic field would be a very good cue to navigate," Kremers told Live Science. "It seems quite plausible for dolphins to have a magnetic sense." Some evidence suggests both dolphin and whale migration routes and offshore live strandings may be related to the Earth's magnetic field, but very little research has investigated whether these animals have a magnetic sense. Kremers and her colleagues found just one study that looked at how dolphins reacted to magnetic fields in a pool; that study found dolphins didn't show any response to the magnetic field. But the animals in that study weren't free to move around, and were trained to give certain responses. © 2014 Scientific American
Keyword: Animal Migration
Link ID: 20140 - Posted: 10.01.2014
By Jia You Fish larvae emit sound—much to the surprise of biologists. A common coral reef fish in Florida, the gray snapper—Lutjanus griseus (pictured above)—hatches in the open ocean and spends its juvenile years in food-rich seagrass beds hiding from predators before settling in the reefs as an adult. To study how larval snappers orient themselves in the dark, marine biologists deployed transparent acrylic chambers equipped with light and sound sensors under the water to capture the swimming schools as they travel to the seagrass beds on new-moon nights. The larval snappers make a short “knock” sound that adults also make, as well as a long “growl” sound, the team reports online today in Biology Letters. The researchers suspect that the larvae use the acoustic signals to communicate with one another and stay together in schools. If so, human noise pollution could be interrupting their communications—even adult fish have been found to “yell” to be heard above boat noises. © 2014 American Association for the Advancement of Science.
Wild marmosets in the Brazilian forest can learn quite successfully from video demonstrations featuring other marmosets, Austrian scientists have reported, showing not only that marmosets are even better learners than previously known, but that video can be used successfully in experiments in the wild. Tina Gunhold, a cognitive biologist at the University of Vienna, had worked with a population of marmoset monkeys in a bit of Brazilian forest before this particular experiment. The forest is not wilderness. It lies near some apartment complexes, and the marmosets are somewhat used to human beings. But the monkeys are wild, and each extended family group has its own foraging territory. Dr. Gunhold and her colleagues reported in the journal Biology Letters this month that they had tested 12 family groups, setting up a series of video monitors, each with a kind of complicated box that they called an “artificial fruit.” All the boxes contained food. Six of the monitors showed just an unchanging image of a marmoset near a similar box. Three of them showed a marmoset opening the box by pulling a drawer, and three others a marmoset lifting a lid to get at the food. Marmosets are very territorial and would not tolerate a strange individual on their turf, but the image of a strange marmoset on video didn’t seem to bother them. Individual marmosets “differed in their reactions to the video,” Dr. Gunhold said. “Some were more shy, some more bold. The younger ones were more attracted to the video, perhaps because of greater curiosity.” © 2014 The New York Times Company
By David Z. Hambrick, Fernanda Ferreira, and John M. Henderson A decade ago, Magnus Carlsen, who at the time was only 13 years old, created a sensation in the chess world when he defeated former world champion Anatoly Karpov at a chess tournament in Reykjavik, Iceland, and the next day played then-top-rated Garry Kasparov—who is widely regarded as the best chess player of all time—to a draw. Carlsen’s subsequent rise to chess stardom was meteoric: grandmaster status later in 2004; a share of first place in the Norwegian Chess Championship in 2006; youngest player ever to reach World No. 1 in 2010; and highest-rated player in history in 2012. What explains this sort of spectacular success? What makes someone rise to the top in music, games, sports, business, or science? This question is the subject of one of psychology’s oldest debates. In the late 1800s, Francis Galton—founder of the scientific study of intelligence and a cousin of Charles Darwin—analyzed the genealogical records of hundreds of scholars, artists, musicians, and other professionals and found that greatness tends to run in families. For example, he counted more than 20 eminent musicians in the Bach family. (Johann Sebastian was just the most famous.) Galton concluded that experts are “born.” Nearly half a century later, the behaviorist John Watson countered that experts are “made” when he famously guaranteed that he could take any infant at random and “train him to become any type of specialist [he] might select—doctor, lawyer, artist, merchant-chief and, yes, even beggar-man and thief, regardless of his talents.” One player needed 22 times more deliberate practice than another player to become a master. © 2014 The Slate Group LLC.
Keyword: Learning & Memory
Link ID: 20136 - Posted: 09.30.2014
By Gary Stix If it’s good for the heart, it could also be good for the neurons, astrocytes and oligodendrocytes, cells that make up the main items on the brain’s parts list. The heart-brain adage comes from epidemiological studies that show that people with cardiovascular risk factors such as high-blood pressure and elevated cholesterol levels, may be more at risk for Alzheimer’s and other dementias. This connection between heart and brain has also led to some disappointments: clinical trials of lipid-lowering statins have not helped patients diagnosed with Alzheimer’s, although epidemiological studies suggest that long-term use of the drugs may help prevent Alzheimer’s and other dementias. The link between head and heart is still being pursued because new Alzheimer’s drugs have failed time and again. One approach that is now drawing some interest looks at the set of proteins that carry around fats in the brain. These lipoproteins could potentially act as molecular sponges that mop up the amyloid-beta peptide that clogs up connections among brain cells in Alzheimer’s. One of these proteins—Apolipoprotein J, also known as clusterin—intrigues researchers because of the way it interacts with amyloid-beta and the status of its gene as a risk factor for Alzheimer’s. A researcher from the University of Minnesota, Ling Li, recently presented preliminary work at the Alzheimer’s Disease Drug Discovery Foundation annual meeting that showed that, at least in a lab dish, a molecule made up of a group of amino acids from APOJ is capable of protecting against the toxicity of the amyloid-beta peptide. It also quelled inflammation and promoted the health of synapses—the junctions where one brain cell encounters another. Earlier work by another group showed that the peptide prevented the development of lesions in the blood vessels of animals.
Link ID: 20135 - Posted: 09.30.2014
by Sarah Zielinski Small, silver fish called Mexican tetra (Astyanax mexicanus) live in some Texas and Mexican rivers. Some members of the species — eyeless and blind — can be found in nearby freshwater caves. Sometimes the sighted fish wash into a cave, but they don’t do nearly as well as their blind brethren. Any surface dweller unlucky enough to end up in the dark would have some disadvantages: It would have to adapt to the loss of light and forage for unfamiliar foods, which may be not as abundant as those found in their home waters. But the fish’s biggest disadvantage may be its metabolism. Blind cavefish have lost their circadian rhythms and have developed more efficient metabolisms than the fish that live in the light, researchers report September 24 in PLOS ONE. To measure tetras’ metabolism, Damian Moran and colleagues at Lund University in Sweden placed fish in a contraption that let the fish swim in place while the researchers tracked their oxygen consumption, a measure of their metabolism. Surface and cave fish were placed in the tank under constant darkness or 12-hour light-and-dark cycles for 7 or 8 days. Then the researchers compared how the fish did under the different light regimes. All the fish took a few days to acclimate to the laboratory conditions. In the light-and-dark conditions, surface fish showed a clear circadian pattern to their oxygen consumption. These fish ramped up their metabolism by about 20 percent during the day. That increase in metabolism would let them have more energy for their hunts and feeding, which take place in the light. © Society for Science & the Public 2000 - 2014
Keyword: Biological Rhythms
Link ID: 20134 - Posted: 09.30.2014
Christie Nicholson reports. Shakespeare called sleep the chief nourisher in life’s feast. But today we know it’s so much more. Insufficient sleep contributes to the risk of cardiovascular disease, diabetes and obesity. And now a study finds that too little or too much sleep are both associated with a significant increase in sick days away from work. Almost 4,000 men and women between 30 and 64 years old (in Finland) participated in the study, which followed them for seven years. The research revealed that the absence from work due to illness increased dramatically for those who said they slept less than 6 hours or more than 9 hours per night. The sleep time that was associated with the lowest number of sick days was 7 hours 38 minutes for women and 7 hours 46 minutes for men. The study is in the journal Sleep. [Tea Lallukka, Sleep and Sickness Absence: A Nationally Representative Register-Based Follow-Up Study] Of course these findings are associative and not necessarily causal. Other factors may be responsible for the under- or oversleeping to begin with. But sleep patterns are still a warning sign for increased illness and health complications. Shakespeare put it best: Sleep…that knits up the ravell’d sleave of care. © 2014 Scientific American
Link ID: 20133 - Posted: 09.30.2014
By Linda Carroll The debate over whether violent movies contribute to real-world mayhem may have just developed a wrinkle: New research suggests they might enhance aggression only in those already prone to it. Using PET scanners to peer into the brains of volunteers watching especially bloody movie scenes, researchers determined that the way a viewer’s brain circuitry responds to violent video depends upon whether the individual is aggressive by nature. The study was published Wednesday in PLOS One. “Just as beauty is in the eye of the beholder, environmental stimuli are in the brain of the beholder,” said Nelly Alia-Klein, the study’s lead author and an associate professor at the Friedman Brain Institute and the Icahn School of Medicine at Mount Sinai Hospital in New York City. To test the importance of personality, Alia-Klein and her colleagues rounded up 54 healthy men, some of whom had a history of getting into physical fights, while the others had no history of aggression. The researchers scanned the volunteers three times: doing nothing, watching emotionally charged video and viewing a violent movie. “It wasn’t the whole [violent] movie,” Alia-Klein said, “just the violent scenes, one after another after another.” Along with the brain scans, the researchers monitored blood pressure and asked about the viewers’ moods every 15 minutes.
Link ID: 20132 - Posted: 09.30.2014
By Dr Michael Mosley BBC Do you have a "male" or "female" brain? Are there really significant brain differences between the sexes and if so, do these differences matter? BBC Horizon investigates. When it comes to the tricky and explosive question of how much, if at all, male and female behaviour is driven by brain differences, Professor Alice Roberts and I sit on different sides of the fence. I believe that our brains, like our bodies, are shaped by exposure to hormones in the womb and this may help explain why males tend to do better at some tasks (3D rotation), while women tend to do better at others (empathy skills), although there is, of course, an awful lot of overlap and social pressure involved. Alice, on the other hand, thinks these differences are largely spurious, the result of how the tests are carried out. She worries that such claims may discourage girls from going into science. "We live in a country where fewer than three out of ten physics A levels are taken by girls, where just 7% of engineers are women" she points out, before adding "and where men still earn on average nearly 20% more than their female colleagues." So the BBC's Horizon programme asked us to go and explore the science, put forward research that would support our different views, but also look for common ground. BBC © 2014
Keyword: Sexual Behavior
Link ID: 20129 - Posted: 09.29.2014
Posted by James Owen in Weird & Wild Bigger males may get a lot of attention, but sometimes being smaller—and sneakier—is more successful when it comes to mating. In the East African cichlid fish, Lamprologus callipterus, males come in two sizes: giants or dwarves that are 40 times smaller than their beefier rivals. (Watch a video of male cichlid fish fighting.) It’s an example of male polymorphism, a phenomenon in which males of the same species take different forms. Though people vary in height, men don’t come in two different sizes like the cichlids. Several research studies suggest that tall men—those over 5’7″—are more successful in dating and in their careers—but they get divorced at higher rates. But the variation in L. callipterus, which are found only in Lake Tanganyika (map), is “the most extreme there is,” said Michael Taborsky, co-director of the Institute of Ecology and Evolution at the University of Bern, Switzerland. “It’s an enormous size difference.” In a new study, published September 17 in the Proceedings of the Royal Society B, Taborsky and his team linked this gulf in size to the female’s unusual habit of laying eggs in empty snail shells. To attract females, the giant males collect hundreds of these shells, using their mouths to create nesting sites. But while their hefty build is ideal for lugging about the heavy shells and chasing off rivals, the giants can’t access the chambers of their female harem, instead releasing their sperm outside the shell, Taborsky explained. (Also see “Small Squid Have Bigger Sperm—And Their Own Sex Position.”) © 1996-2013 National Geographic Societ
Keyword: Sexual Behavior
Link ID: 20127 - Posted: 09.29.2014
By Bec Crew Mike meet everyone, everyone meet Mike. No, no, don’t wave. He can’t see, you’re just making this awkward. Also known as Miracle Mike, Mike the Headless Chicken was a plump, five-year-old cockerel when he was unceremoniously beheaded on 10 September 1945. Farmer Lloyd Olsen of Fruita in Colorado did the deed because his wife Clara was having her mother over for dinner that night, and Olsen knew she’d always enjoyed a bit of roast chicken neck. With that in mind, Olsen tried to save most of Mike’s neck as he lopped his head off, but in doing so, he accidentally made his axe miss Mike’s jugular vein, plus one ear and most of his brain stem, and to his surprise, Mike didn’t die. In fact, Mike stuck around for a good 18 months without his head. Immediately after it happened, Mike reeled around like any headless chicken would, but soon settled down. He even started pecking at the ground for food with his newly minted stump, and made preening motions. His crows had become throaty gurglings. Olsen, bewildered, left him to it. The next morning, when Olsen found Mike asleep in the barn, having attempted to tuck his head under his wing as he always had, the farmer took it upon himself to figure out how to feed this unwitting monstrosity. Mike had earned that much. All Olsen had to do was deposit food and water into Mike’s exposed oesophagus via a little eyedropper. He even got small grains of corn sometimes as a treat. © 2014 Scientific American
Link ID: 20126 - Posted: 09.29.2014
by Bethany Brookshire Isaac Newton famously showed that in physics, every action has an equal and opposite reaction. A similar push-and-pull of positive and negative inputs also exists in our brains. Brain cells can send out excitatory chemical signals, and they can also receive inhibitory chemical signals, putting the brakes on further signaling. This delicate balance of excitation and inhibition allows our brains to function normally and to react to the world around us. A new study shows that the same neurons contribute excitatory and inhibitory chemical signals in a brain area linked with how we process disappointment, and that antidepressants might be able to change this delicate molecular dance and stop some of the negative thought cycles associated with depression. But while the work finds an association, it’s not yet proof that the balance of these chemicals holds the key to relieving depressive symptoms. The study, published September 19 in Science, focuses on the lateral habenula. This tiny area makes up the “stalk” connecting the pineal gland to the rest of the brain. It receives inputs from areas of the brain important in reward and emotional processing, including the basal ganglia. Some areas of the brain appear to specialize in predicting rewards, showing increases in activity in response to enjoyable things such as food, sex or drugs. Activity in these areas lets us know when things are about to get good. But for every high there is a low. The lateral habenula is thought to play a role in how we process negative events: Getting a lemon on the slot machine again or the empty inbox on your dating site. Studies in monkeys and other animals have shown that increased activity in the habenula is linked to depressive behaviors, and treatment with antidepressants decreases this activity. In addition, a study in rats and a 2009 case study in a human patient showed that deep-brain stimulation in the lateral habenula could relieve symptoms of depression. © Society for Science & the Public 2000 - 2014.
Link ID: 20125 - Posted: 09.27.2014