Chapter 11. Motor Control and Plasticity

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Henry Astley In the Mark Twain story The Celebrated Jumping Frog of Calaveras County, a frog named Daniel Webster "could get over more ground at one straddle than any animal of his breed you ever see." Now, scientists have visited the real Calaveras County in hopes of learning more about these hopping amphibians. They’ve found that what they see in the lab doesn’t always match the goings-on in the real world. If you wanted to know how far the bullfrog Rana catesbeiana could jump, the scientific literature would give you one answer: 1.295 meters, published in Smithsonian Contributions to Zoology in 1978. If you looked at the Guinness Book of World Records, though, you'd find a different answer. In 1986, a bullfrog called Rosie the Ribeter covered 6.55 meters in three hops. If you divide by three, at least one of those hops had to be no shorter than 2.18 meters—about four bullfrog body lengths more than the number in the scientific paper. The disparity matters. If bullfrogs can hop only 1.3 meters, they have enough power in their muscles to pull off the jump without any other anatomical help. But if they can jump farther, they must also be using a stretchy tendon to power their hops—an ability that other frogs have but that researchers thought bullfrogs had lost. These particular amphibians, scientists speculated, might have made some kind of evolutionary tradeoff that shortened their jumps but enabled them to swim better in the water, where they spend much of their lives. © 2013 American Association for the Advancement of Science

Keyword: Miscellaneous
Link ID: 18800 - Posted: 10.17.2013

By Lary C. Walker Clumps of proteins twisted into aberrant shapes cause the prion diseases that have perplexed biologists for decades. The surprises just keep coming with a new report that the simple clusters of proteins responsible for Mad Cow and other prions diseases may, without help from DNA or RNA, be capable of changing form to escape the predations of drugs that target their eradication. Prion drug resistance could be eerily similar to that found in cancer and HIV—and may have implications for drug development for Alzheimer’s and Parkinson’s, neurodegenerative diseases also characterized by misfolded proteins. Prion diseases include scrapie, chronic wasting disease and bovine spongiform encephalopathy (mad cow disease) in nonhuman species, and Creutzfeldt-Jakob disease and fatal insomnia in humans. They are unusual in that they can arise spontaneously, as a result of genetic mutations, or, in some instances, through infection. Remarkably, the infectious agent is not a microbe or virus, but rather the prion itself, a clump of proteins without genetic material. The noxious agents originate when a normally generated protein – called the prion protein – mistakenly folds into a stable, sticky, and potentially toxic shape. When the misfolded protein contacts other prion protein molecules, they too are corrupted and begin to bind to one another. In the ensuing chain reaction, the prions grow, break apart, and spread; within the nervous system, they relentlessly destroy neurons, ultimately, and invariably, leading to death. © 2013 Scientific American

Keyword: Prions; Aggression
Link ID: 18799 - Posted: 10.17.2013

Kashmira Gander A team in Bristol have created an implant that encourages cells damaged by the disease to grow again. It does this through a system of tubes and catheters that pump proteins into patients’ brain once a month, potentially stopping the disease from progressing by encouraging the damaged cells to grow again. The port located behind a patient’s ear releases a protein called glial cell line-derived neurotrophic factor (GDNF). Six patients at Frenchay Hospital, Bristol, have trialled the system, and doctors are now looking for another 36 to help them continue their research. Dr Kieran Breen, director of research and innovation at Parkinson's UK, said: “For years, the potential of GDNF as a treatment for Parkinson's has remained one of the great unanswered research questions. ”This new study will take us one step closer to finally answering this question once and for all. “We believe GDNF could have the potential to unlock a new approach for treating Parkinson's that may be able to slow down and ultimately stop the progression of the condition all together. ”Currently there are very few treatments available for people with Parkinson's and none capable of stopping the condition from advancing.“ More than 127,000 people in the UK currently have the disease, which is caused when nerve cells in the brain die due to a lack of the chemical dopamine. Symptoms include slowness of movement, stiffness and tremors. © independent.co.uk

Keyword: Parkinsons; Aggression
Link ID: 18783 - Posted: 10.14.2013

Mind over matter. New research explains how abstract benefits of exercise—from reversing depression to fighting cognitive decline—might arise from a group of key molecules. While our muscles pump iron, our cells pump out something else: molecules that help maintain a healthy brain. But scientists have struggled to account for the well-known mental benefits of exercise, from counteracting depression and aging to fighting Alzheimer’s and Parkinson’s disease. Now, a research team may have finally found a molecular link between a workout and a healthy brain. Much exercise research focuses on the parts of our body that do the heavy lifting. Muscle cells ramp up production of a protein called FNDC5 during a workout. A fragment of this protein, known as irisin, gets lopped off and released into the bloodstream, where it drives the formation of brown fat cells, thought to protect against diseases such as diabetes and obesity. (White fat cells are traditionally the villains.) While studying the effects of FNDC5 in muscles, cellular biologist Bruce Spiegelman of Harvard Medical School in Boston happened upon some startling results: Mice that did not produce a so-called co-activator of FNDC5 production, known as PGC-1α, were hyperactive and had tiny holes in certain parts of their brains. Other studies showed that FNDC5 and PGC-1α are present in the brain, not just the muscles, and that both might play a role in the development of neurons. © 2013 American Association for the Advancement of Science.

Keyword: Depression
Link ID: 18781 - Posted: 10.12.2013

By JAMES GORMAN SEATTLE — To hear Michael Dickinson tell it, there is nothing in the world quite as wonderful as a fruit fly. And it’s not because the fly is one of the most important laboratory animals in the history of biology, often used as a simple model for human genetics or neuroscience. “I don’t think they’re a simple model of anything,” he says. “If flies are a great model, they’re a great model for flies. “These animals, you know, they’re not like us,” he says, warming to his subject. “We don’t fly. We don’t have a compound eye. I don’t think we process sensory information the same way. The muscles that they use are just incredibly much more sophisticated and interesting than the muscles we use. “They can taste with their wings,” he adds, as his enthusiasm builds. “No one knows any reason why they have taste cells on their wing. Their bodies are just covered with sensors. This is one of the most studied organisms in the history of science, and we’re still fundamentally ignorant about many features of its basic biology. It’s like having an alien in your lab. “And,” he says, pausing, seeming puzzled that the world has not joined him in open-mouthed wonder for his favorite creature, “they can fly!” If he had to define his specialty, Dr. Dickinson, 50, who counts a MacArthur “genius” award among his honors, would call himself a neuroethologist. As such, he studies the basis of behavior in the brain at the University of Washington, in Seattle. In practice he is a polymath of sorts who has targeted the fruit fly, Drosophila melanogaster, and its flying behavior for studies that involve physics, mathematics, neurobiology, computer vision, muscle physiology and other disciplines. © 2013 The New York Times Company

Keyword: Movement Disorders
Link ID: 18762 - Posted: 10.08.2013

by Colin Barras It's like pulling a rabbit out of a hat. Researchers have reached inside the brain of a rat and pulled out neural stem cells – without harming the animal. Since the technique uses nanoparticles already approved for use in humans, it is hoped that it could be used to extract neural stem cells (NSCs) from people to treat conditions like Parkinson's, Huntington's and multiple sclerosis. Extracting NSCs from the person who needs them would avoid immune rejection – but they are difficult to remove safely. So Edman Tsang at the University of Oxford and his colleagues have developed a technique to safely fish out NSCs that originate in cavities in the brain called ventricles. Tsang's team coated magnetic nanoparticles with antibodies that bond tightly to a protein found on the surface of NSCs. They then injected the nanoparticles into the lateral ventricles of rats' brains. Six hours later, after the nanoparticles had bonded to the NSCs, the researchers used a magnetic field around the rats' heads to pull the stem cells together. They could then be sucked out of the brain with a syringe. After freeing the stem cells from the nanoparticles, the team found they could grow them in a dish, suggesting they were undamaged by the process. The rats, meanwhile, were back on their feet within hours of the surgery, showing no ill effects. © Copyright Reed Business Information Ltd.

Keyword: Stem Cells; Aggression
Link ID: 18737 - Posted: 10.03.2013

By NICHOLAS BAKALAR Depression may be an independent risk factor for Parkinson’s disease, a new study has found. In a retrospective analysis, researchers followed 4,634 patients with depression and 18,544 matched controls for 10 years. To rule out the possibility that depression is an early symptom of Parkinson’s disease, their analysis excluded patients who received a diagnosis of depression within five years of their Parkinson’s diagnosis. The average age of people with depression was 41, while it was 64 for those with both depression and Parkinson’s. The study, published online in Neurology, found that 66 patients with depression, or 1.42 percent, developed Parkinson’s disease, compared with 97, or 0.52 percent, among those who were not depressed. After controlling for age, sex, diabetes, hypertension and other factors, the researchers found clinical depression was associated with more than three times the risk for Parkinson’s disease. “Our paper does not convey the message that all depression leads to Parkinson’s disease,” said the senior author, Dr. Albert C. Yang, a professor of psychiatry at the National Yang-Ming University in Taiwan. “But particularly the depressed elderly and those with difficult-to-treat depression should be alert to the possibility of neurological disease and Parkinson’s.” Copyright 2013 The New York Times Company

Keyword: Depression; Aggression
Link ID: 18735 - Posted: 10.03.2013

Erika Check Hayden The power of thought alone is not enough to move inanimate objects — unless the object is a robotic leg wired to your brain, that is. A 32-year-old man whose knee and lower leg were amputated in 2009 after a motorcycle accident is apparently the first person with a missing lower limb to control a robotic leg with his mind. A team led by biomedical engineer Levi Hargrove at the Rehabilitation Institute of Chicago in Illinois reported the breakthrough last week in the New England Journal of Medicine1, including a video that shows the man using the bionic leg to walk up stairs and down a ramp, and to kick a football. The major advance is that the man does not have to use a remote-control switch or exaggerated muscle movements to tell the robotic leg to switch between types of movements, and he does not have to reposition the leg with his hands when seated, Hargrove says. “To our knowledge, this is the first time that neural signals have been used to control both a motorized knee and ankle prosthesis,” he says. Scientists had previously shown that paralysed people could move robotic arms using their thoughts and that able-bodied people can walk using robotic legs controlled by their brains (see, for example, go.nature.com/dgtykw). The latest work goes a step further by using muscle signals to amplify messages sent by the brain when the person intends to move. © 2013 Nature Publishing Group

Keyword: Robotics
Link ID: 18725 - Posted: 10.01.2013

Ballet dancers develop differences in their brain structures to allow them to perform pirouettes without feeling dizzy, a study has found. A team from Imperial College London said dancers appear to suppress signals from the inner ear to the brain. Dancers traditionally use a technique called "spotting", which minimises head movement. The researchers say their findings may help patients who experience chronic dizziness. Dizziness is the feeling of movement when, in reality, you are still. For most it is an occasional, temporary sensation. But around one person in four experiences chronic dizziness at some point in their life. When someone turns or spins around rapidly, fluid in the vestibular organs of the inner ear can be felt moving through tiny hairs. Once they stop, the fluid continues to move, which can make a person feel like they are still spinning. Ballet dancers train hard to be able to spin, or pirouette, rapidly and repeatedly. They use a technique called spotting, focusing on a spot on the floor - as they spin, their head should be the last bit to move and the first to come back. In the study, published in the journal Cerebral Cortex, the team recruited 29 female ballet dancers and 20 female rowers of similar age and fitness levels. BBC © 2013

Keyword: Miscellaneous
Link ID: 18709 - Posted: 09.28.2013

By Todd Sherer Parkinson’s disease is coming to prime time. Tomorrow night Michael J. Fox returns to television as the star of his own sitcom nearly 15 years after retiring from Spin City to focus on finding a cure for his disease. Michael has been careful to emphasize that the show isn’t really about Parkinson’s. Based loosely on his real life, The Michael J. Fox Show mines laughs from the everyday trials and tribulations of family man Mike Henry as he resumes his TV news job following a Parkinson’s diagnosis. Yet simply by featuring a main character living with the disease, the show puts Parkinson’s into the national conversation. This is a good moment to consider how much work remains to be done in the realm of neurodegeneration research. The question we’ve heard most often at The Michael J. Fox Foundation is: After more than 20 years with Parkinson’s, how is Michael doing well enough to go back to work? There’s no simple answer. He acknowledges the good fortune he has in a loving, supportive family and financial independence, which have provided advantages in dealing with his disease. He says, “Everybody gets their own version of Parkinson’s. Different meds work for different people, and you’re always trying to find the perfect combination. I think I found what works for me right now. And I’m so lucky.” But the reality is that for the estimated five million Parkinson’s patients worldwide, the status quo is still not good enough. They are living with Parkinson’s movement difficulties and nonmotor symptoms such as mood and sleep disorders as well as cognitive impairment. Medication and therapies alleviate some symptoms, but create their own problems and fail to address all the effects of Parkinson’s. We have some disease-modifying treatments in clinical trials, but nothing on the market yet. The grim truth is that those diagnosed with Parkinson’s will get worse. And for every patient, a community is affected, as the impact of the disease ripples to loved ones and caregivers. This is a global problem, but one that we can solve. © 2013 Scientific American

Keyword: Parkinsons
Link ID: 18708 - Posted: 09.26.2013

by Colin Barras A man missing his lower leg has gained precise control over a prosthetic limb, just by thinking about moving it – all because his unused nerves were preserved during the amputation and rerouted to his thigh where they can be used to communicate with a robotic leg. The man can now seamlessly switch from walking on level ground to climbing stairs and can even kick a football around. During a traditional limb amputation, the main sensory nerves are severed and lose their function. In 2006, Todd Kuiken and his colleagues at the Rehabilitation Institute of Chicago in Illinois realised they could preserve some of that functionality by carefully rerouting sensory nerves during an amputation and attaching them to another part of the body. They could then use the rerouted nerve signals to control a robotic limb, allowing a person to control their prosthesis with the same nerves they originally used to control their real limb. Kuiken's team first attempted the procedure – which is called targeted muscle reinnervation (TMR) – on people who were having their arm amputated. Now, Kuiken's team has performed TMR for the first time on a man with a leg amputation. First, the team rerouted the two main branches of the man's sciatic nerve to muscles in the thigh above the amputation. One branch controls the calf and some foot muscles, the other controls the muscle running down the outside leg and some more foot muscles. © Copyright Reed Business Information Ltd

Keyword: Robotics
Link ID: 18707 - Posted: 09.26.2013

By Ingrid Wickelgren An attractive blonde in a bright red blouse sits in a wheelchair before the assembled scientists, doctors, writers and members of the community. We are in a conference room at the Aspen Meadows Resort, the site of the 2013 Aspen Brain Forum. Amanda Boxtel recalls what life was like for her at 24. She had been a skier, a runner and a ballet dancer, she tells us. She liked to hike in the wilderness. Pictures of a beautiful young woman appear on a screen. In the photos, she’s standing. Then one day on a slope, the tips of Boxtel’s skis crossed. She did a somersault and shattered four vertebrae. “I also shattered illusions of my immortality. I was paralyzed from here”—she hold her hands at her hips—“down. No movement and no sensation.” That life changed radically for her right then is difficult to dispute. But Boxtel eventually embraced a road to recovery. “It took time to turn wounds into wisdom. It took guts. This is a cruel injury. It is so much more than not being able to walk,” she tells us. With the aid of adaptive technology, she got back on her skis. She took up waterskiing, rock climbing, kayaking and hang gliding. But still, she couldn’t bear weight on her legs or walk. Walking seems easy to most of us, because the action is built-in; it is automatic. In reality, however, walking is a highly complex motion involving many different muscles that must contract in a precisely timed sequence. Once the spinal cord can no longer orchestrate this motion, it is exceedingly hard to replicate. Walking, for Boxtel, was arguably a pipe dream. And so she sat for 21 years. © 2013 Scientific American

Keyword: Robotics
Link ID: 18699 - Posted: 09.25.2013

By Melissa Hogenboom Science reporter, BBC News Moving in time to a steady beat is closely linked to better language skills, a study suggests. People who performed better on rhythmic tests also showed enhanced neural responses to speech sounds. The researchers suggest that practising music could improve other skills, particularly speech. In the Journal of Neuroscience, the authors argue that rhythm is an integral part of language. "We know that moving to a steady beat is a fundamental skill not only for music performance but one that has been linked to language skills," said Nina Kraus, of the Auditory Neuroscience Laboratory at Northwestern University in Illinois. More than 100 teenagers were asked to tap their fingers along to a beat. Their accuracy was measured by how closely their responses matched the timing of a metronome. Next, in order to understand the biological basis of rhythmic ability, the team also measured the brainwaves of their participants with electrodes, a technique called electroencephalography. This was to observe the electrical activity in the brain in response to sound. Using this biological approach, the researchers found that those who had better musical training also had enhanced neural responses to speech sounds. In poorer readers this response was diminished. BBC © 2013

Keyword: Language; Aggression
Link ID: 18665 - Posted: 09.18.2013

By Associated Press, Former Grateful Dead drummer Mickey Hart has a new piece of equipment accompanying him on his latest tour: a cap fitted with electrodes that capture his brain activity and direct the movements of a light show while he’s jamming on stage. The sensor-studded headgear is an outgrowth of collaboration between Hart, 70, and Adam Gazzaley, a University of California at San Francisco neuroscientist who studies cognitive decline. The subject has been an interest of the musician’s since the late 1980s, as he watched his grandmother deal with Alzheimer’s disease. When he played the drums for her, he says, she became more responsive. Since then, Hart has invested time and money exploring the therapeutic potential of rhythm. Thirteen years ago, he founded Rhythm for Life, a nonprofit promoting drum circles for the elderly. Hart first publicly wore his electroencephalogram cap last year at an AARP convention where he and Gazzaley discussed their joint pursuit of research on the link between brain waves and memory. He wore it again while making his new album, “Superorganism,” translating the rhythms of his brain waves into music. Hart’s bandmates, with input from other researchers in Gazzaley’s lab, paired different waves with specific musical sequences that were then inserted into songs. © 1996-2013 The Washington Post

Keyword: Brain imaging; Aggression
Link ID: 18656 - Posted: 09.17.2013

Insect leg cogs a first in animal kingdom Philip Ball If you are a young plant hopper, leaping one metre in a single bound, you need to push off with both hind legs in perfect unison or you might end up in a spin. Researchers have discovered that this synchrony is made possible by toothed gears that connect the two legs when the insects jump. Zoologists Malcolm Burrows and Gregory Sutton at the University of Cambridge, UK, say that this seems to be the first example in nature of rotary motion with toothed gears. They describe their findings today in Science1. When the insect jumps, the cog teeth join so that the two legs lock together, ensuring that they thrust at exactly the same time (see video above and image at left). “The gears add an extra level of synchronization beyond that which can be achieved by the nervous system,” says Burrows. Infant plant hoppers, known as nymphs, can take off in just 2 milliseconds, reaching take-off speeds of almost 4 metres a second (see video below). For motions this rapid, some mechanical device is needed to keep the legs synchronized and to avoid lopsided jumps that might lead to the insects spinning out of control. The problem does not, however, arise in all jumping insects: whereas the attachments of plant hoppers' hind legs are adjacent to each other, the legs of grasshoppers and fleas attach to opposite the sides of the body and move in parallel planes. This helps to stabilize the insects and even enables them to jump one-legged. © 2013 Nature Publishing Group

Keyword: Miscellaneous
Link ID: 18644 - Posted: 09.14.2013

By Athena Andreadis Recently, two studies surfaced almost simultaneously that led to exclamations of “Vulcan mind meld!”, “Zombie armies!” and “Brains in jars!” One is the announcement by Rajesh Rao and Andrea Stocco of Washington U. that they “achieved the first human-to-human brain interface”. The other is the Nature paper by Madeline Lancaster et al about stem-cell-derived “organoids” that mimic early developmental aspects of the human cortex. My condensed evaluation: the latter is far more interesting and promising than the former, which doesn’t quite do what people (want to) think it’s doing. The purported result of brain interfacing hit many hot buttons that have been staples of science fiction and Stephen King novels: primarily telepathy, with its fictional potential for non-consensual control. Essentially, the sender’s EEG (electroencephalogram) output was linked to the receiver’s TMS (transcranial magnetic stimulation) input. What the experiment actually did is not send a thought but induce a muscle twitch; nothing novel, given the known properties of the two technologies. The conditions were severely constrained to produce the desired result and I suspect the outcome was independent of the stimulus details: the EEG simply recorded that a signal had been produced and the TMS apparatus was positioned so that a signal would elicit a movement of the right hand. Since both sender and receiver were poised over a keyboard operating a video game, the twitch was sufficient to press the space bar, programmed by the game to fire a cannon. © 2013 Scientific American

Keyword: Robotics
Link ID: 18623 - Posted: 09.10.2013

American researchers say they’ve performed what they believe is the first ever human-to-human brain interface, where one person was able to send a brain signal to trigger the hand motions of another person. “It was both exciting and eerie to watch an imagined section from my brain get translated into actual action by another brain,” said Rajesh Rao, a professor of computer science and engineering at the University of Washington, in a statement. Previous studies have done brain-to-brain transmissions between rats and one was done between a human and a rat. Rao was able to send a brain signal through the internet – utilizing electrical brain recordings and a form of magnetic stimulation – to the other side of the university campus to his colleague Andrea Stocco, an assistant professor of psychology, triggering Stocco’s finger to move on a keyboard. “The internet was a way to connect computers, and now it can be a way to connect brains,” said Stocco. “We want to take the knowledge of a brain and transmit it directly from brain to brain.” On Aug. 12, Rao sat in his lab with a cap on his head. The cap had electrodes hooked up to an electroencephalography machine, which reads the brain’s electrical activity. Meanwhile, Stocco was at his lab across campus, wearing a similar cap which had a transcranial magnetic stimulation coil place over his left motor cortex – the part of the brain that controls hand movement. Rao looked at a computer and in his mind, he played a video game. When he was supposed to fire a cannon at a target, he imagined moving his right hand, which stayed motionless. Stocco, almost instantaneously, moved his right index finger to push the space bar on the keyboard in front of him. Only simple brain signals, not thoughts “This was basically a one-way flow of information from my brain to his,” said Rao. © CBC 2013

Keyword: Robotics; Aggression
Link ID: 18583 - Posted: 08.29.2013

By GRETCHEN REYNOLDS As a clinical psychologist and sleep researcher at the Feinberg School of Medicine at Northwestern University, Kelly Glazer Baron frequently heard complaints from aggrieved patients about exercise. They would work out, they told her, sometimes to the point of exhaustion, but they would not sleep better that night. Dr. Baron was surprised and perplexed. A fan of exercise for treating sleep problems, but also a scientist, she decided to examine more closely the day-to-day relationship between sweat and sleep. What she and her colleagues found, according to a study published last week in The Journal of Clinical Sleep Medicine, is that the influence of daily exercise on sleep habits is more convoluted than many of us might expect and that, in the short term, sleep might have more of an impact on exercise than exercise has on sleep. To reach that conclusion, Dr. Baron and her colleagues turned to data from a study of exercise and sleep originally published in 2010. For that experiment, researchers had gathered a small group of women (and one man) who had received diagnoses of insomnia. The volunteers were mostly in their 60s, and all were sedentary. Then the researchers randomly assigned their volunteers either to remain inactive or to begin a moderate endurance exercise program, consisting of three or four 30-minute exercise sessions a week, generally on a stationary bicycle or treadmill, that were performed in the afternoon. This exercise program continued for 16 weeks. At the end of that time, the volunteers in the exercise group were sleeping much more soundly than they had been at the start of the study. They slept, on average, about 45 minutes to an hour longer on most nights, waking up less often and reporting more vigor and less sleepiness. Copyright 2013 The New York Times Company

Keyword: Sleep
Link ID: 18575 - Posted: 08.28.2013

By Katherine Harmon The eight wily arms of an octopus can help the animal catch dinner, open a jar and even complete a convincing disguise. But these arms are not entirely under the control of the octopus’s brain. And new research shows just how deep their independence runs—even when they are detached. The octopus’s nervous system is a fascinating one. Some two thirds of its neurons reside not in its central brain but out in its flexible, stretchable arms. This, researchers suspect, lightens the cognitive coordination demands and allows octopuses to let their arms do some of the “thinking”—or at least the coordination, problem-solving and reaction—on their own. And these arms can continue reacting to stimuli even after they are no longer connected to the main brain; in fact, they remain responsive even after the octopus has been euthanized and the arms severed. The research is in the special September 2013 issue of the Journal of Experimental Marine Biology and Ecology called “Cephalopod Biology” (we’ll check out the other fascinating studies in days and weeks ahead). The researchers, working at St. George’s University of London and the Anton Dohrn Zoological Station in Naples, Italy, examined 10 adult common octopuses (Octopus vulgaris) that had been collected and used for other studies. After the animals were euthanized, their arms were removed and kept in chilled seawater for up to an hour until they were ready for experimentation. Some arms were suspended vertically, and others were laid out horizontally. When pinched, suspended arms recoiled from the unpleasant stimulus by shortening and curling in a corkscrew shape within one second. © 2013 Scientific American

Keyword: Miscellaneous
Link ID: 18573 - Posted: 08.28.2013

By Felicity Muth Humans love their victory displays. You only have to watch a game of football (or soccer to US-readers) to see some victory displays of the most ridiculous kind. Why do people do such things? If there was no crowd there, it is unlikely that they would perform such displays. But is it for the sake of the sex they are wishing to attract, or perhaps to put people they are competing with in no doubt of their accomplishment? Other animals, of course, also compete with each other, for food, resources and mates. And, like humans, how they behave once they win or lose a competition may depend on who’s around to see it. Male spring crickets fight with each other for territories and females Male spring field crickets fight with other males. The winners tend to do a lot better with the lady crickets, as the winners may gain the best territory, and because females of this species prefer dominant males. Now for the part that may surprise you: the males that win these fights will perform a victory display just like humans – after beating another male, the male winner performs an aggressive song and jerks his body in a particular way to show off that he’s won this fight. But, like with humans, the question arises: why do males do these victory displays? Is it to show the loser male that he has lost, or to show other males and females that he’s won? © 2013 Scientific American

Keyword: Sexual Behavior; Aggression
Link ID: 18569 - Posted: 08.27.2013