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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

Related chapters from BP7e: Chapter 11: Motor Control and Plasticity
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 18644 - Posted: 09.14.2013

By Laura Sanders Rats spent hours in a state of chilly suspended animation after researchers injected a compound into the animals in a cold room. The animals’ heart rates slowed, brain activity became sluggish and body temperature plummeted. The research joins a small number of studies that attempt to induce the metabolically lethargic state known as torpor in animals that can’t normally slow their metabolism. “It’s a breakthrough” in understanding aspects of torpor, says neuroscientist Kelly Drew of the University of Alaska Fairbanks. Lowering the body temperature of a nonhibernating mammal is really hard, says Domenico Tupone of Oregon Health & Science University in Portland. As temperatures inside the body fall, several failsafe systems spring into action. Blood vessels near the skin squeeze tight to hold warmth in, the body starts to shiver and brown fat, a tissue that’s especially plentiful in newborns, starts to produce heat. But Tupone and colleagues bypassed the rats’ defenses against the cold with a compound that’s similar to adenosine, a molecule in the body that signals sleepiness. After about an hour in a room chilled to 15° Celsius, the rats grew lethargic. Their brain waves slowed, their blood pressure dropped and their heart grew sluggish, occasionally skipping beats. The rats’ core temperature dropped from about 38° to about 30° C, or 80° Fahrenheit, the authors report in the Sept. 4 Journal of Neuroscience. Tupone and his colleagues measured even lower temperatures in further experiments — rats’ core body temperature reached 15° C or about 57° F. “That is a pretty amazing temperature. No one has done this before,” he says. © Society for Science & the Public 2000 - 2013

Related chapters from BP7e: Chapter 13: Homeostasis: Active Regulation of the Internal Environment
Related chapters from MM:Chapter 9: Homeostasis: Active Regulation of the Internal Environment
Link ID: 18609 - Posted: 09.05.2013

By Felicity Muth In my previous post, I talked about how crickets were influenced by who was watching them when they performed a victory dance after winning a fight. Although this is a unique finding, it fits into a larger picture of many animals (including insects) being affected by their social context. At the animal behaviour conference I went to in Colorado (where I heard both about the cricket research and about the study I’m going to write about today), you could see how people were affected by what others were doing around them. When one person sneaked out before the end of a talk to go to a talk in a different room, a load of other people would follow. When chatting with a friend, a person would modify what they were saying depending on who else was in the vicinity. Whether we are aware of it all of the time or not, we constantly modify our behaviour depending on the social context we’re in. Well, in addition to crickets, it turns out that honeybees are affected by social context too. This isn’t surprising, given that these bees are highly social animals, but quite how they are affected is rather interesting. Honeybees live in colonies of up to 40, 000 – 80, 000 individuals, almost all females. Like humans, honeybees like to keep their dwelling at constant temperature, not least to make sure that their brood can develop. Unlike humans however, bees think around 36°C (96.8°F) is a great temperature to have their home at. In the winter, honeybees shiver to produce heat, pressing their abdomens against their brood (stored in cells) to distribute the heat more evenly. In the summer however, it can get pretty hot, and so the bees use some strategies to cool down that are not dissimilar to our own. They collect water that can evaporate in the colony and cool it down. They also fan to circulate air around the colony. However, until recently it was not clear how bees decide to start fanning, and whether this might be influenced by what others are doing. © 2013 Scientific American

Related chapters from BP7e: Chapter 13: Homeostasis: Active Regulation of the Internal Environment
Related chapters from MM:Chapter 9: Homeostasis: Active Regulation of the Internal Environment
Link ID: 18586 - Posted: 08.31.2013

Karen Ravn It’s safe to say that wildlife biologist Lynn Rogers gets along better with the black bears in Minnesota than with the humans in the state’s Department of Natural Resources. Rogers, a popular bear researcher who has made numerous TV appearances, is engaged in quite a row with the department. At issue: should the department renew Rogers’ permit to study black bears? In June, the department said “no.” But trying to come between Rogers and his bears is a bit like trying to come between a mother bear and her cubs. He took the agency to court, and late last month, the parties came to a temporary agreement. Rogers can keep radio collars on the ten research bears that have them now, but he can’t keep live-streaming video on the Internet from his internationally popular den cams. His case will go back to court in six to nine months. Earlier this month, Rogers received a big boost from renowned chimpanzee researcher Jane Goodall, who wrote to Minnesota governor Mark Dayton praising Rogers and saying that it would be “a scientific tragedy” if his research were ended now. The department gave three reasons for not renewing Rogers’ permit: he hadn’t produced any peer-reviewed publications based on data collected over the past 14 years when he had a permit; his work was endangering the public; and he had engaged in unprofessional conduct. © 2013 Nature Publishing Group

Related chapters from BP7e: Chapter 1: Biological Psychology: Scope and Outlook; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 1: An Introduction to Brain and Behavior
Link ID: 18577 - Posted: 08.29.2013

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

Related chapters from BP7e: Chapter 11: Motor Control and Plasticity
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 18573 - Posted: 08.28.2013

By Scicurious Optogenetics likes to light up debate. Optogenetics is a hot technique in neuroscience research right now, involving taking a light-activited gene (called a channel rhodopsin) targeted into a single neuron type, and inserting it into the genome of, say, a mouse (yes, we can do this now). When you then shine a light into the mouse’s brain, the channel rhodopsin responds, and the neurons that are now expressing the channel rhodopsin fire. This means that you can get a single type of neuron to fire (or not, there are ones that inhibit firing, too), whenever you want to, merely by turning on a light. I actually remember where I WAS when I first heard of optogenetics. I came into the lab in the morning, was going about my daily business, and hadn’t checked the daily Tables of Contents for journals yet (I get these delivered into my email). I remember the postdoc, normally a pretty phlegmatic person, actually putting a little excitement into their voice, “hey guys, look at this.” The paper was this one. We all crowded around. It took us all a few minutes to “get it”. As it began to sink it, I had two thoughts. The first? “WHOA, THAT IS AWESOME.” The second? “Great, I know what’s going to be the hot stuff now.” There are fashions in science. Not the kind where everyone dyes their lab coat plaid or creates cutoffs out of their Personal Protective Equipment (though that would be hilarious). There are experimental fashions. Lesions were once really “in”. Knockouts were hot stuff in the 90s. fMRI enjoyed (and still does enjoy) its moment in the sun, electrophysiology often adds a little je ne sais quoi to a paper. DREADDs, CLARITY. And when a new thing comes along and is going to be hot? You can sniff it out a mile away. For next year? I’m betting on GEVIs, myself. They’ll be all the rage. © 2013 Scientific American

Related chapters from BP7e: Chapter 3: Neurophysiology: The Generation, Transmission, and Integration of Neural Signals
Related chapters from MM:Chapter 3: Neurophysiology: The Generation, Transmission, and Integration of Neural Signals
Link ID: 18565 - Posted: 08.27.2013

By April Neale An innovative two-part series, "Brains on Trial with Alan Alda," airing Wednesday, September 11 and 18, 2013, 10-11 p.m. on PBS (check local listings), explores how the growing ability to separate truth from lies, even decode people’s thoughts and memories, may radically affect how criminal trials are conducted in the future. As brain scanning techniques advance, their influence in criminal cases is becoming critically important. Brains on Trial centers around the trial of a fictional crime: a robbery staged in a convenience store that has been filmed by the store’s security cameras. A teenager stands accused of the attempted murder of the store clerk’s wife who was shot during the crime. While the crime is fictional, the trial is conducted before a real federal judge and argued by real practicing attorneys. The program is divided into two-parts: the first hour examines the guilt phase of the trial concluding with the jury’s verdict; the second hour looks at the sentencing phase, when arguments for and against a severe sentence are heard. As the trial unfolds, Alda visits with neuroscientists whose research has already influenced some Supreme Court decisions, as well as Duke University law professor Nita Farahany, a member of the Presidential Commission for the Study of Bioethical Issues. On these visits, neuroscientists show how functional MRIs and other brain scanning techniques are exploring lie detection, facial recognition, memory decoding, racial bias, brain maturity, intention, and even emotions. The research Alda discovers is at the center of a controversy as to how this rapidly expanding ability to peer into people’s minds and decode their thoughts and feelings could – or should – affect trials like the one presented in the program. As DNA evidence has played a major role in exonerating innocent prisoners, Brains on Trial asks if neuroscience can make the criminal justice system more just.

Related chapters from BP7e: Chapter 1: Biological Psychology: Scope and Outlook
Related chapters from MM:Chapter 1: An Introduction to Brain and Behavior
Link ID: 18527 - Posted: 08.20.2013

By Neuroskeptic Back in April a paper came out in Nature Reviews Neuroscience that shocked many: Katherine Button et al’s Power failure: why small sample size undermines the reliability of neuroscience It didn’t shock me, though, skeptic that I am: I had long suspected that much of neuroscience (and science in general) is underpowered – that is, that our sample sizes are too small to give us an acceptable chance of detecting the signals that we claim to be able to isolate out of the noise. In fact, I was so unsurprised by Button et al that I didn’t even read it, let alone write about it, even though the authors list included such neuro-blog favorites as John Ionaddis, Marcus Munafo and Brian Nosek (I try to avoid obvious favouritism, you see). However this week I took a belated look at the paper, and I noticed something interesting. Button et al took 49 meta-analyses and calculated the median observed statistical power of the studies in each analysis. The headline finding was that average power is small. I was curious to know why it was small. So I correlated the study characteristics (sample size and observed effect size) with the median power of the studies. I found that median power in a given meta-analysis was not correlated with the median sample size of those studies (d on the left, RR on the right):

Related chapters from BP7e: Chapter 1: Biological Psychology: Scope and Outlook
Related chapters from MM:Chapter 1: An Introduction to Brain and Behavior
Link ID: 18487 - Posted: 08.12.2013

Brain cells talk to each other in a variety of tones. Sometimes they speak loudly but other times struggle to be heard. For many years scientists have asked why and how brain cells change tones so frequently. Today National Institutes of Health researchers showed that brief bursts of chemical energy coming from rapidly moving power plants, called mitochondria, may tune brain cell communication. “We are very excited about the findings,” said Zu-Hang Sheng, Ph.D., a senior principal investigator and the chief of the Synaptic Functions Section at the NIH’s National Institute of Neurological Disorders and Stroke (NINDS). “We may have answered a long-standing, fundamental question about how brain cells communicate with each other in a variety of voice tones.” The network of nerve cells throughout the body typically controls thoughts, movements and senses by sending thousands of neurotransmitters, or brain chemicals, at communication points made between the cells called synapses. Neurotransmitters are sent from tiny protrusions found on nerve cells, called presynaptic boutons. Boutons are aligned, like beads on a string, on long, thin structures called axons. They help control the strength of the signals sent by regulating the amount and manner that nerve cells release transmitters. Mitochondria are known as the cell’s power plant because they use oxygen to convert many of the chemicals cells use as food into adenosine triphosphate (ATP), the main energy that powers cells. This energy is essential for nerve cell survival and communication. Previous studies showed that mitochondria can rapidly move along axons, dancing from one bouton to another.

Related chapters from BP7e: Chapter 3: Neurophysiology: The Generation, Transmission, and Integration of Neural Signals; Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Related chapters from MM:Chapter 3: Neurophysiology: The Generation, Transmission, and Integration of Neural Signals; Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Link ID: 18414 - Posted: 07.27.2013

By Sue Shellenbarger It’s easy to be offended when a colleague yawns while you’re talking. But that yawn may not mean what you think. A growing number of researchers believe the purpose of this little-understood behavior is to cool the brain, says a research review published earlier this year in Frontiers in Neuroscience. Changes in climate affect how often people yawn. Researchers in an earlier study asked two groups of pedestrians in Tucson, Ariz., one in early summer and one in the winter. People were asked to look at pictures of people yawning and talk about their own yawning behavior. The participants were nearly twice as likely to yawn when they were surveyed during the winter, when they could inhale cool air to reduce the temperature of the brain, says the study, published in 2011 in Frontiers in Evolutionary Neuroscience. Participants yawned less when surveyed in the early summer, when temperatures outdoors were about the same as the human body. Other studies show yawning increases after people experience heat stress or have a heat pack placed on their foreheads. Yawning also may build empathy within groups. Yawns are seen as contagious, but “catching” a yawn depends on a person’s ability to feel empathy and closeness with the yawner, says a 2013 research review in the International Journal of Applied Basic Medical Research. ©2013 Dow Jones & Company, Inc.

Related chapters from BP7e: Chapter 13: Homeostasis: Active Regulation of the Internal Environment
Related chapters from MM:Chapter 9: Homeostasis: Active Regulation of the Internal Environment
Link ID: 18383 - Posted: 07.18.2013

Gregory Gage is being honored as a Champion of Change for his dedication to increasing public engagement in science and science literacy. Science has a rich history of everyday citizens assisting in great discoveries, and I am honored that our work to encourage amateur neuroscience has been selected by The White House for the Citizen Science Champion of Change award. We know a lot about how our amazing brain works, but there is much, much more that remains to be discovered. In fact, we have no cures and only insufficient treatments for neurological disorder, even though about 1 out of every 5 people will be diagnosed with a brain disease. Change is indeed needed in our nation’s approach to science education to bring more focus on neuroscience. I am a “DIY” neuroscientist. I co-founded a low-fi company called Backyard Brains with my grad-school labmate, Tim Marzullo. While working on our Ph.D., we would often go out to local public schools to talk about the importance of studying neuroscience. We developed our lesson plans using models and analogies about how the brain works, but what we really wanted to teach the students was “electrophysiology”... as this is truly is how the brain works. The brain is an electrical organ, and the cells (neurons) communicate with “spikes”: a brief pulse of electricity. In my research at the university, I would record these spikes to learn what the neurons were telling us about how the brain worked. Traditionally, to do experiments with electrophysiology, one needs to be in a Ph.D. program and use expensive equipment (our electrophysiology rig cost $40,000). To make this accessible for our outreach goals, Tim and I set out on a self-imposed engineering challenge: to reduce this equipment down to the basic components, and record a spike for <$100. Less than a year later, we got our first prototype to work and were able to bring spikes into the classrooms! After getting requests from colleagues and teachers, we launched Backyard Brains. We are now a growing education company with neuroscience gear in over 45 countries on all 7 continents!

Related chapters from BP7e: Chapter 3: Neurophysiology: The Generation, Transmission, and Integration of Neural Signals; Chapter 1: Biological Psychology: Scope and Outlook
Related chapters from MM:Chapter 3: Neurophysiology: The Generation, Transmission, and Integration of Neural Signals; Chapter 1: An Introduction to Brain and Behavior
Link ID: 18349 - Posted: 07.06.2013

Posted by Gary Marcus Aristotle thought that the function of the brain was to cool the blood. That seems ludicrous now; through neuroscience, we know more about the brain and how it works than ever before. But, over the past several years, enthusiasm has often outstripped the limits of what current science can really tell us, and the field has given rise to pop neuroscience, which attempts to explain practically everything about human behavior and culture through the brain and its functions. A backlash against pop neuroscience is now in full swing. The latest, and most cutting, critique yet is “Brainwashed: The Seductive Appeal of Mindless Neuroscience,” by Sally Satel and Scott Lilienfeld. The book, which slams dozens of inconclusive studies that have been spun into overblown and downright dubious fields, like neurolaw and neuromarketing, is a resounding call for skepticism of the most grandiose claims being made in the name of neuroscience. The authors describe it as “an exposé of mindless neuroscience: the oversimplification, interpretive license, and premature application of brain science in the legal, commercial, clinical, and philosophical domains." The book does a terrific job of explaining where and how savvy readers should be skeptical. Unfortunately, the book is also prone to being misread. This is partly because it focusses largely on neuroscience’s current limitations rather than on its progress. Some, like David Brooks in the New York Times, are using books like “Brainwashed” as an excuse to toss out neuroscience altogether. In Brooks’s view, Satel and Lilienfeld haven’t just exposed some bad neuroscience; they’ve gutted the entire field, leading to the radical conclusion that “the brain is not the mind.” Brooks goes so far as to suggest that “it is probably impossible to look at a map of brain activity and predict or even understand the emotions, reactions, hopes and desires of the mind,” and that “there appears to be no dispersed pattern of activation that we can look at and say, ‘That person is experiencing hatred.’ ” The core of his claim is the idea that, if activity is distributed throughout the brain, it cannot be understood or interpreted. © 2013 Condé Nast.

Related chapters from BP7e: Chapter 1: Biological Psychology: Scope and Outlook; Chapter 2: Functional Neuroanatomy: The Nervous System and Behavior
Related chapters from MM:Chapter 1: An Introduction to Brain and Behavior; Chapter 2: Cells and Structures: The Anatomy of the Nervous System
Link ID: 18294 - Posted: 06.22.2013

By Jason G. Goldman Within the wildlife conservation community, both in the field (“in situ“) as well as in captive settings (“ex situ“), there is a great deal of folk knowledge about the best methods for animal care as well as species protection and restoration. Increasingly, however, empirical knowledge from psychology and cognitive science can be brought to bear on husbandry, management, and conservation-related issues and can inform best practices. Here’s one small example. At the Los Angeles Zoo, I recently participated in a study with on the effects of environmental enrichment on meerkat behavior. Thoughtfully designed environmental enrichment programs, it is thought, allow captive animals to display a wider variety of naturalistic behaviors. A wealth of evidence suggests that when animals exhibit their natural behaviors, zoo visitors have a better and more educational experience, and animal welfare is increased. Unfortunately, one side effect of captivity is the possible emergence of non-naturalistic repetitive or stereotypic behaviors. Stereotypic behaviors vary according to the species, but might include swaying, coprophagy, regurgitation and reingestion, or pacing. When combined with stereotypic swimming patterns, pacing may actually be the most common form of stereotypy across species in modern zoos. While these behaviors may in fact be more stressful for zoo visitors than for the animals themselves, zoos still have a responsibility to minimize them as much as possible. Other stereotypies may feature or result in various forms of self-harm, which are of course more dangerous. Birds pluck their feathers, horses nip at their flanks, canids, felids, and bears over-groom themselves, turtles may bite their legs, and snakes may chew on their tails. © 2013 Scientific American

Related chapters from BP7e: Chapter 1: Biological Psychology: Scope and Outlook
Related chapters from MM:Chapter 1: An Introduction to Brain and Behavior
Link ID: 18245 - Posted: 06.08.2013

By IAN LOVETT WEST HOLLYWOOD, Calif. — A potentially deadly strain of meningitis, which has left one resident brain dead, has sent a shiver through the large gay community here, as public health officials have urged residents to be on the lookout for any symptoms of the disease. Although only one case has been confirmed in the area, officials said, the onset follows an outbreak of deadly meningitis among gay men in New York City. At least 22 men have contracted meningitis in New York since 2010, 13 of them this year, and 7 have died. Health officials have not yet determined if there is any connection between the cases in New York and the one here. But the similarities have ignited fears that this case could be an early sign of a bicoastal outbreak. “The lesson we learned 30 years ago in the early days of H.I.V. and AIDS is that people were not alerted to what was going on and a lot of infections occurred that didn’t need to occur,” said John Duran, a West Hollywood city councilman and one of the few openly H.I.V.-positive elected officials in the country. “So even with an isolated case here, we need to sound the alarms, especially given the cases in New York.” In New York, the city health department issued a warning last month, urging all men who regularly have intimate contact with other men to be vaccinated for meningitis. Officials here have thus far been reluctant to do the same. At a news conference on Friday, Dr. Maxine E. Liggins, with the Los Angeles County Department of Public Health, warned residents to watch for early signs of meningococcal meningitis, including a severe headache and stiff neck. The disease, a bacterial infection of the membrane surrounding the brain and the spinal cord, can be effectively treated with antibiotics if detected early, although it can intensify quickly. © 2013 The New York Times Company

Related chapters from BP7e: Chapter 2: Functional Neuroanatomy: The Nervous System and Behavior
Related chapters from MM:Chapter 2: Cells and Structures: The Anatomy of the Nervous System
Link ID: 18034 - Posted: 04.15.2013

By Suzy Gage When I started my PhD a few years ago, I thought that certain psychological findings were established fact. The next four years were an exercise in disillusionment. If the effects I was seeking to explore were so reliable, so established, why could I not detect them? There is growing interest in the need to improve reliability in science. Many drugs show promise at the design and pre-clinical phases, only to fail (at great expense) in clinical trials. Many of the most hyped scientific discoveries eventually cannot be replicated. Worryingly for science (but somewhat comforting for my self-esteem as a researcher) this may be because many of the conclusions drawn from published research findings are false. A major factor that influences the reliability of science is statistical power. We cannot measure everyone or everything, so we take samples and use statistical inference to determine the probability that the results we observe in our sample reflect some underlying scientific truth. Statistical power determines whether we accurately conclude if there is an effect or not. Statistical power is the ability of a study to detect an effect (eg higher rates of cancer in smokers) given that an effect actually exists (smoking actually is associated with increased risk of cancer). Power is related to the size of the study sample (the number of smokers and non-smokers we test) and the size of the real effect (the magnitude of the increased risk associated with smoking). Larger studies have more power and can detect smaller, more subtle effects. Small studies have lower power and can only detect larger effects reliably. © 2013 Guardian News and Media Limited

Related chapters from BP7e: Chapter 1: Biological Psychology: Scope and Outlook
Related chapters from MM:Chapter 1: An Introduction to Brain and Behavior
Link ID: 18019 - Posted: 04.11.2013

By George Johnson The mystery of whether there is a natural resonance between music and our brains, as I mentioned in a post last week, brings up an even deeper question: whether mathematics itself is neurologically innate, giving the mind (or some minds) direct access to the structure of the universe. Thinking about that recently led me back to one of Oliver Sack’s most astonishing essays. It appeared in his collection The Man Who Mistook His Wife for a Hat, and is about two twins, idiot savants who appeared to have an almost supernatural ability to quickly tell if a number is prime. Prime numbers are those that cannot be broken down into factors — smaller numbers that can be multiplied together to produce the larger one. They have been described as the atoms of the number system. 11 and 13 are obviously prime while 12 and 14 are not. But with larger numbers our brains are quickly flummoxed. Is 7244985277 prime? I just typed the digits by twitching my fingers along the top row of my keyboard. To test the number by hand I would have to start at the beginning of the number system and begin trying out the possible divisors. There are shortcuts to avoid testing every single one. We know 2 can’t be a factor since 7244985277, like all primes, is odd. For the same reason we can rule out all even factors. And you only have to test factors up to the square root of a number. (The factors of 100 are 2 x 50, 4 x 25, 5 x 20, and 10 x 10. Testing beyond 10 would be redundant.)

Related chapters from BP7e: Chapter 18: Attention and Higher Cognition
Related chapters from MM:Chapter 14: Attention and Consciousness
Link ID: 17847 - Posted: 02.26.2013

By Jason Bittel Bears hibernate. They spend all year eating salmon, blueberries, and picnic baskets and then, sometime around baseball playoffs, they all wander off to a cave full of treasure and explorers’ skulls where they curl up in a big furry ball and snore away the winter. Everybody knows this! Even small children too young to attend to their own biological functions know how these wild animals make it through a period of harsh weather and food shortage. But beyond the fact that bears den up in winter, what do we really know of these lumbering slumber beasts and the secrets they keep beneath the ice and snow? Let’s start with this bit of housekeeping—cursory Googling of bears and hibernation will lead you to all sorts of trash talk saying bears aren’t “true hibernators.” True hibernators, such as Arctic ground squirrels, are capable of dropping their body temperatures below the freezing point of water, conditions so cold that neurons in the brain’s cortex are physically incapable of firing. Not to mention you can do all sorts of awful things to true hibernators while they slumber—like, oh, I don’t know, locking marmots in airtight jars filled with carbonic acid and hydrogen. (Easy, PETA. We’re talking 1832.) I know what you’re thinking: First Lance Armstrong, then Manti Te’o, and now this. But before you sit the kids down and blow their fragile little minds with the message that bears may not be true hibernators, consider that science is something of a moving target. The more we learn, the more questions we raise. © 2013 The Slate Group, LLC

Related chapters from BP7e: Chapter 13: Homeostasis: Active Regulation of the Internal Environment
Related chapters from MM:Chapter 9: Homeostasis: Active Regulation of the Internal Environment
Link ID: 17812 - Posted: 02.18.2013

by Sara Reardon In the Arctic winter, it is not even worth getting up in the morning. It's freezing cold and the sun never rises, making it impossible to tell night from day. So each autumn, when the Arctic ground squirrel (Spermophilus parryii) heads underground to hibernate for eight months, it doesn't even bother setting its circadian clock. During hibernation, the squirrel goes into a state akin to suspended animation. It cuts itself off from the world and allows its body temperature to drop to -3 °C while it sleeps – the lowest ever body temperature recorded in a mammal. Once it wakes up for the summer, however, the squirrel can switch its daily clock back on. The squirrels' sub-zero tolerance was first discovered almost 25 years ago. Curious how the animals manage to survive the frigid Arctic winter where temperatures regularly drop to -30 °C, Brian Barnes of the University of Alaska in Fairbanks implanted radio transmitters into the stomachs of captive squirrels, which transmitted information on their body temperature, before letting them build burrows for the winter. Once the squirrels went into their deep sleep, Barnes found that their core body temperature dropped from about 36 °C to -3 °C. To prevent their blood from freezing, the squirrels cleanse it of any particles that water molecules could form ice crystals around. This allows the blood to remain liquid below zero, a phenomenon known as supercooling. © Copyright Reed Business Information Ltd.

Related chapters from BP7e: Chapter 13: Homeostasis: Active Regulation of the Internal Environment
Related chapters from MM:Chapter 9: Homeostasis: Active Regulation of the Internal Environment
Link ID: 17715 - Posted: 01.26.2013

By Ashutosh Jogalekar G Protein-Coupled Receptors (GPCRs) are the messengers of the human body, key proteins whose ubiquitous importance was validated by the 2012 Nobel Prize in chemistry. As I mentioned in a post written after the announcement of the prize, GPCRs are involved in virtually every physiological process you can think of, from sensing colors, flavors and smells to the action of neurotransmitters and hormones. In addition they are of enormous commercial importance, with something like 30% of marketed drugs binding to these proteins and regulating their function. These drugs include everything from antidepressants to blood-pressure lowering medications. But GPCRs are also notoriously hard to study. They are hard to isolate from their protective lipid cell membrane, hard to crystallize and hard to coax into giving up their molecular secrets. One reason the Nobel Prize was awarded was because the two researchers – Robert Lefkowitz and Brian Kobilka – perfected techniques to isolate, stabilize, crystallize and study these complex proteins. But there’s still a long way to go. There are almost 800 GPCRs, out of which ‘only’ 16 have been crystallized during the past decade or so. In addition all the studied GPCRs are from the so-called Class A family. There’s still five classes left to decipher, and these contain many important receptors including the ones involved in smell. Clearly it’s going to be a long time before we can get a handle on the majority of these important proteins. Fortunately there’s something important that GPCR researchers have realized; it’s the fact that many of these GPCRs have amino acid sequences that are similar. If you know what experimental conditions work for one protein, perhaps you can use the same conditions for another similar GPCR. © 2013 Scientific American

Related chapters from BP7e: Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology; Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology; Chapter 5: The Sensorimotor System
Link ID: 17692 - Posted: 01.17.2013

By CLAUDIA DREIFUS In a world of proliferating professions, S. Matthew Liao has a singular title: neuroethicist. Dr. Liao, 40, the director of the bioethics program at New York University, deploys the tools of philosophy, history, psychology, religion and ethics to understand the impact of neuroscientific breakthroughs. You’re a philosopher by training. How did philosophy lead to neuroethics? Mine’s the typical immigrant’s story. My family moved to Cincinnati from Taiwan in the early 1980s. Once here, my siblings gravitated towards the sciences. I was the black sheep. I was in love with the humanities. So I didn’t go to M.I.T. — I went to Princeton, where I got a degree in philosophy. This, of course, worried my parents. They’d never met a philosopher with a job. Do you have any insight on why scientific careers are so attractive to new Americans? You don’t need to speak perfect English to do science. And there are job opportunities. Define neuroethics. It’s a kind of subspecialty of bioethics. Until very recently, the human mind was a black box. But here we are in the 21st century, and now we have all these new technologies with opportunities to look inside that black box — a little. With functional magnetic imaging, f.M.R.I., you can get pictures of what the brain is doing during cognition. You see which parts light up during brain activity. Scientists are trying to match those lights with specific behaviors. At the same time this is moving forward, there are all kinds of drugs being developed and tested to modify behavior and the mind. So the question is: Are these new technologies ethical? © 2012 The New York Times Company

Related chapters from BP7e: Chapter 1: Biological Psychology: Scope and Outlook
Related chapters from MM:Chapter 1: An Introduction to Brain and Behavior
Link ID: 17614 - Posted: 12.18.2012