Chapter 6. Evolution of the Brain and Behavior

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Ruth Williams If a mouse is in a lot of pain, an experienced handler may see it in the animal’s facial expression—its narrowed eyes and bulging cheeks. But, subtler facial expressions may be more difficult to match to their moods. So researchers developed an unbiased machine learning approach to study hundreds of videos of mice and, as a result, have now catalogued a range of emotion-specific facial expressions. These expressions, the researchers show, can serve as handy readouts for studying the neural basis of emotions. “It’s a tour de force in terms of techniques,” says neuroscientist Sheena Josselyn of the University of Toronto who was not involved in the research. “Using the techniques . . . they are really beginning to give [emotion] a scientific definition, which I think is really important.” “The results provide an important advance by adding quantitative analysis of facial motor patterns to the repertoire of ‘emotional’ behaviors that can be measured in mice,” David Anderson, a neuroscientist at Caltech, writes in an email to The Scientist. That’s important, he adds, because “facial expressions have been considered as key indicators of emotion state in mammals, but have previously been measured in rodents only in a more qualitative, subjective manner.” Anderson, who studies the neurobiology of emotional behaviors, was also not involved in the project. Previous investigations of facial expressions in mice and other animals not only lacked objectivity, they tended to focus on just one or two emotions, says Nadine Gogolla of the Max Planck Institute of Neurobiology. “None of those studies looked at a whole spectrum [of emotions] and whether they can be distinguished from each other.” © 1986–2020 The Scientist.

Keyword: Emotions; Evolution
Link ID: 27170 - Posted: 04.04.2020

By Laura Sanders Although it’s tricky for us humans to see, mouse feelings are written all over their furry little faces. With machine learning tools, researchers reliably spotted mice’s expressions of joy, fear, pain and other basic emotions. The results, published in the April 3 Science, provide a field guide for scientists seeking to understand how emotions such as joy, regret and empathy work in animals other than humans (SN: 11/10/16; SN: 6/9/14; SN: 12/8/11). Using machine learning to reveal mice’s expressions is “an extraordinarily exciting direction,” says Kay Tye, a neuroscientist at the Salk Institute for Biological Studies in La Jolla, Calif. The findings “lay the foundation for what I expect will be a game changer for neuroscience research on emotional states.” Neuroscientist Nadine Gogolla of the Max Planck Institute of Neurobiology in Martinsried, Germany, and colleagues gave mice experiences designed to elicit distinct emotions. Sugar water evoked pleasure, a shock to the tail triggered pain, bitter quinine water created disgust, an injection of lithium chloride evoked a nauseated malaise, and a place where shocks previously had been delivered sparked fear. For each setup, high-speed video cameras captured subtle movements in the mice’s ears, noses, whiskers and other parts of the face. Observers can generally see that something is happening on the mouse’s face, Gogolla says. But translating those subtle clues into emotions is really hard, “especially for an untrained human being,” she says. © Society for Science & the Public 2000–2020

Keyword: Emotions; Evolution
Link ID: 27168 - Posted: 04.03.2020

By Bruce Bower Lucy’s kind had small, chimplike brains that, nevertheless, grew at a slow, humanlike pace. This discovery, reported April 1 in Science Advances, shows for the first time that prolonged brain growth in hominid youngsters wasn’t a by-product of having unusually large brains. An influential idea over the last 20 years has held that extended brain development after birth originated in the Homo genus around 2.5 million years ago, so that mothers — whose pelvic bones and birth canal had narrowed to enable efficient upright walking — could safely deliver babies. But Australopithecus afarensis, an East African hominid species best known for Lucy’s partial skeleton, also had slow-developing brains that reached only about one-third the volume of present-day human brains, say paleoanthropologist Philipp Gunz of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and his colleagues. And A. afarensis is roughly 3 million to 4 million years old, meaning slow brain growth after birth developed before members of the Homo genus appeared, perhaps as early as 2.8 million years ago (SN: 3/4/15). Too few A. afarensis infants have been studied to calculate the age at which this species attained adult-sized brains, Gunz cautions. The brains of human infants today reach adult sizes by close to age 5, versus an age of around 2 or 3 for both chimps and gorillas. In the new study, Gunz and colleagues estimated brain volumes for six A. afarensis adults and two children, estimated to have been about 2 years and 5 months old. The kids had brains that were smaller than adult A. afarensis brain sizes in a proportion similar to human children’s brains at the same age relative to adult humans. © Society for Science & the Public 2000–2020.

Keyword: Evolution; Development of the Brain
Link ID: 27163 - Posted: 04.02.2020

By Matt McGrath Environment correspondent A new study that looks at lifespan in wild mammals shows that females live substantially longer than males. The research finds that, on average, females live 18.6% longer than males from the same species. This is much larger than the well-studied difference between men and women, which is around 8%. The scientists say the differences in these other mammals are due to a combination of sex-specific traits and local environmental factors. In every human population, women live longer than men, so much so that nine out of 10 people who live to be 110 years old are female. This pattern, researchers say, has been consistent since the first accurate birth records became available in the 18th Century. While the same assumption has been held about animal species, large-scale data on mammals in the wild has been lacking, Now, an international team of researchers has examined age-specific mortality estimates for a widely diverse group of 101 species. In 60% of the analysed populations, the scientists found that females outlived the males - on average, they had a lifespan that's 18.6% longer than males. "The magnitude of lifespan and ageing across species is probably an interaction between environmental conditions and sex-specific genetic variations," said lead author Dr Jean-Francois Lemaître, from the University of Lyon, France. He gives the example of bighorn sheep for which the researchers had access to good data on different populations. Where natural resources were consistently available there was little difference in lifespan. However, in one location where winters were particularly severe, the males lived much shorter lives. © 2020 BBC.

Keyword: Sexual Behavior; Evolution
Link ID: 27137 - Posted: 03.24.2020

By Virginia Morell Whether it’s calculating your risk of catching the new coronavirus or gauging the chance of rain on your upcoming beach vacation, you use a mix of statistical, physical, and social information to make a decision. So do New Zealand parrots known as keas, scientists report today. It’s the first time this cognitive ability has been demonstrated outside of apes, and it may have implications for understanding how intelligence evolved. “It’s a neat study,” says Karl Berg, an ornithologist and parrot expert at the University of Texas Rio Grande Valley, Brownsville, who was not involved with this research. Keas already had a reputation in New Zealand—and it wasn’t a great one. The olive-brown, crow-size birds can wield their curved beaks like knives—and did so on early settlers’ sheep, slicing through wool and muscle to reach the fat along their spines. These days, they’re notorious for slashing through backpacks for food and ripping windshield wipers off cars. To see whether keas’ intelligence extended beyond being mischievous, Amalia Bastos, a doctoral candidate in comparative psychology at the University of Auckland, and colleagues turned to six captive keas at a wildlife reserve near Christchurch, New Zealand. The researchers taught the birds that a black token always led to a tasty food pellet, whereas an orange one never did. When the scientists placed two transparent jars containing a mix of tokens next to the keas and removed a token with a closed hand, the birds were more likely to pick hands dipped into jars that contained more black than orange tokens, even if the ratio was as close as 63 to 57. That experiment combined with other tests “provide conclusive evidence” that keas are capable of “true statistical inference,” the scientists report in today’s issue of Nature Communications. © 2020 American Association for the Advancement of Science

Keyword: Evolution; Attention
Link ID: 27092 - Posted: 03.04.2020

Nicola Davis From humans to black-tailed prairie dogs, female mammals often outlive males – but for birds, the reverse is true. Now researchers say they have cracked the mystery, revealing that having two copies of the same sex chromosome is associated with having a longer lifespan, suggesting the second copy offers a protective effect. “These findings are a crucial step in uncovering the underlying mechanisms affecting longevity, which could point to pathways for extending life,” the authors write. “We can only hope that more answers are found in our lifetime.” The idea that a second copy of the same sex chromosome is protective has been around for a while, supported by the observation that in mammals – where females have two of the same sex chromosomes – males tend to have shorter lifespans. In birds, males live longer on average and have two Z chromosomes, while females have one Z and one W chromosome. Scientists say they have found the trend is widespread. Writing in the journal Biology Letters, the team report that they gathered data on sex chromosomes and lifespan across 229 animal species, from insects to fish and mammals. Hermaphroditic species and those whose sex is influenced by environmental conditions – such as green turtles – were not included. The results reveal that individuals with two of the same sex chromosomes live 17.6% longer, on average, than those with either two different sex chromosomes or just one sex chromosome. The team say the findings back a theory known as the “unguarded X hypothesis”. In human cells, sex chromosome combinations are generally either XY (male) or XX (female). In females only one X chromosome is activated at random in each cell. © 2020 Guardian News & Media Limited

Keyword: Sexual Behavior; Evolution
Link ID: 27090 - Posted: 03.04.2020

By Laura Sanders Here’s something neat about sleeping sheep: Their brains have fast zags of neural activity, similar to those found in sleeping people. Here’s something even neater: These bursts zip inside awake sheep’s brains, too. These spindles haven’t been spotted in healthy, awake people’s brains. But the sheep findings, published March 2 in eNeuro, raise that possibility. The purpose of sleep spindles, which look like jagged bursts of electrical activity on an electroencephalogram, isn’t settled. One idea is that these bursts help lock new memories into the brain during sleep. Daytime ripples, if they exist in people, might be doing something similar during periods of wakefulness, the researchers speculate. Jenny Morton, a neurobiologist at the University of Cambridge, and her colleagues studied six female merino sheep with implanted electrodes that spanned their brains. The team collected electrical patterns that emerged over two nights and a day. As the sheep slept, sleep spindles raced across their brains. These spindles are akin to those in people during non-REM sleep, which accounts for the bulk of an adult’s sleeping night (SN: 8/10/10). But the electrodes also caught spindles during the day, when the sheep were clearly awake. These “wake” spindles “looked different from those we saw at night,” Morton says, with different densities, for instance. Overall, these spindles were also less abundant and more localized, captured at single, unpredictable spots in the sheep’s brains. © Society for Science & the Public 2000–2020.

Keyword: Sleep; Evolution
Link ID: 27089 - Posted: 03.03.2020

By James Gorman There’s something about a really smart dog that makes it seem as if there might be hope for the world. China is in the midst of a frightening disease outbreak and nobody knows how far it will spread. The warming of the planet shows no signs of stopping; it reached a record 70 degrees in Antarctica last week. Not to mention international tensions and domestic politics. But there’s a dog in Norway that knows not only the names of her toys, but also the names of different categories of toys, and she learned all this just by hanging out with her owners and playing her favorite game. So who knows what other good things could be possible? Right? This dog’s name is Whisky. She is a Border collie that lives with her owners and almost 100 toys, so it seems like things are going pretty well for her. Even though I don’t have that many toys myself, I’m happy for her. You can’t be jealous of a dog. Or at least you shouldn’t be. Whisky’s toys have names. Most are dog-appropriate like “the colorful rope” or “the small Frisbee.” However, her owner, Helge O. Svela said on Thursday that since the research was done, her toys have grown in number from 59 to 91, and he has had to give some toys “people” names, like Daisy or Wenger. “That’s for the plushy toys that resemble animals like ducks or elephants (because the names Duck and Elephant were already taken),” he said. During the research, Whisky proved in tests that she knew the names for at least 54 of her 59 toys. That’s not just the claim of a proud owner, and Mr. Svela is quite proud of Whisky, but the finding of Claudia Fugazza, an animal behavior researcher from Eötvös Loránd University in Budapest, who tested her. That alone makes Whisky part of a very select group, although not a champion. You may recall Chaser, another Border collie that knew the names of more than 1,000 objects and also knew words for categories of objects. And there are a few other dogs with shockingly large vocabularies, Dr. Fugazza said, including mixed breeds, and a Yorkie. These canine verbal prodigies are, however, few and far between. “It is really, really unusual, and it is really difficult to teach object names to dogs,” Dr. Fugazza said. © 2020 The New York Times Company

Keyword: Language; Learning & Memory
Link ID: 27063 - Posted: 02.21.2020

Amy Schleunes New Zealand’s North Island robins (Petroica longipes), known as toutouwai in Maori, are capable of remembering a foraging task taught to them by researchers for up to 22 months in the wild, according to a study published on February 12 in Biology Letters. These results echo the findings of a number of laboratory studies of long-term memory in animals, but offer a rare example of a wild animal retaining a learned behavior with no additional training. The study also has implications for conservation and wildlife management: given the birds’ memory skills, researchers might be able to teach them about novel threats and resources in their constantly changing habitat. “This is the first study to show [memory] longevity in the wild,” says Vladimir Pravosudov, an animal behavior researcher at the University of Nevada, Reno, who was not involved in the study. Rachael Shaw, a coauthor and behavioral ecologist at Victoria University in New Zealand, says she was surprised that the birds remembered the new skill she had taught them. “Wild birds have so much that they have to contend with in their daily lives,” she says. “You don’t really expect that it’s worth their while to retain this learned task they hardly had the opportunity to do, and they can’t predict that they will have an opportunity to do again.” Shaw is generally interested in the cognitive abilities of animals and the evolution of intelligence, and the toutouwai, trainable food caching birds that can live up to roughly 10 years, make perfect subjects for her behavioral investigations. “They’ve got this kind of boldness and curiosity that a lot of island bird species share,” says Shaw. These qualities make them vulnerable to predation by invasive cats, rats, and ermines (also known as stoats), but also inquisitive and relatively unafraid of humans, an ideal disposition for testing memory retention in the field. © 1986–2020 The Scientist

Keyword: Learning & Memory; Evolution
Link ID: 27053 - Posted: 02.20.2020

By Elizabeth Pennisi Scientists seeking the origins of sleep may have uncovered important clues in the Australian bearded dragon. By tracing sleep-related neural signals to a specific region of the lizard’s brain—and linking that region to a mysterious part of the mammalian brain—a new study suggests complex sleep evolved even earlier in vertebrate evolution than researchers thought. The work could ultimately shed light on the mechanisms behind sleep—and pave the way for studies that may help humans get a better night’s rest. “Answers to the questions raised and reframed by this research seem extremely likely to be significant in many ways, including clinically,” says Stephen Smith, a neuroscientist at the Allen Institute who was not involved with the new study. Mammals and birds have two kinds of sleep. During rapid eye movement (REM) sleep, eyes flutter, electrical activity moves through the brain, and, in humans, dreaming occurs. In between REM episodes is “slow wave” sleep, when brain activity ebbs and electrical activity synchronizes. This less intense brain state may help form and store memories, a few studies have suggested. In 2016, Gilles Laurent, a neuroscientist at the Max Planck Institute for Brain Research, discovered that reptiles, too, have both kinds of sleep. Every 40 seconds, central bearded dragons (Pogona vitticeps) switch between the two sleep states, he and his colleagues reported. © 2019 American Association for the Advancement of Science

Keyword: Sleep; Evolution
Link ID: 27037 - Posted: 02.13.2020

By Veronique Greenwood When you look at a reconstruction of the skull and brain of Neoepiblema acreensis, an extinct rodent, it’s hard to shake the feeling that something’s not quite right. Huddled at the back of the cavernous skull, the brain of the South American giant rodent looks really, really small. By some estimates, it was around three to five times smaller than scientists would expect from the animal’s estimated body weight of about 180 pounds, and from comparisons to modern rodents. In fact, 10 million years ago the animal may have been running around with a brain weighing half as much as a mandarin orange, according to a paper published Wednesday in Biology Letters. The glory days of rodents, in terms of the animals’ size, were quite a long time ago, said Leonardo Kerber, a paleontologist at Universidade Federal de Santa Maria in Brazil and an author of the new study. Today rodents are generally dainty, with the exception of larger creatures like the capybara that can weigh as much as 150 pounds. But when it comes to relative brain size, N. acreensis, represented in this study by a fossil skull unearthed in the 1990s in the Brazilian Amazon, seems to be an extreme. The researchers used an equation that relates the body and brain weight of modern South American rodents to get a ballpark estimate for N. acreensis, then compared that with the brain weight implied by the volume of the cavity in the skull. The first method predicted a brain weighing about 4 ounces, but the volume suggested a dinky 1.7 ounces. Other calculations, used to compare the expected ratio of the rodent’s brain and body size with the actual fossil, suggested that N. acreensis’ brain was three to five times smaller than one would expect. © 2020 The New York Times Company

Keyword: Evolution; Brain imaging
Link ID: 27035 - Posted: 02.13.2020

Joanna McKittrick, Jae-Young Jung Slamming a beak against the trunk of a tree would seem like an activity that would cause headaches, jaw aches and serious neck and brain injuries. Yet woodpeckers can do this 20 times per second and suffer no ill effects. Woodpeckers are found in forested areas worldwide, except in Australia. These birds have the unusual ability to use their beaks to hammer into the trunks of trees to make holes to extract insects and sap. Even more impressive they do this without hurting themselves. We are materials scientists who study biological substances like bones, skins, feathers and shells found in nature. We are interested in the skull and tongue bone structure of woodpeckers, because we think their unusual anatomy could yield insights that could help researchers develop better protective head gear for humans. Concussions in people Woodpeckers endure many high impact shocks to their heads as they peck. They have strong tail feathers and claws that help them keep their balance as their head moves toward the tree trunk at 7 meters – 23 feet – per second. Then, when their beak strikes, their heads slow down at about 1,200 times the force of gravity (g). All of this occurs without the woodpecker sustaining concussions or brain damage. A concussion is a form of traumatic brain injury caused by repeated blows to the head. It is a common occurrence and happens frequently during contact sports like football or hockey. Repeated traumatic brain injury eventually causes a progressive brain disorder, chronic traumatic encephalopathy (CTE), which is irreversible and results in symptoms such as memory loss, depression, impulsivity, aggressiveness and suicidal behavior. The National Football League says concussions in football players occur at 80 g. So how do woodpeckers survive repeated 1,200 g impacts without harming their brain? © 2010–2020, The Conversation US, Inc.

Keyword: Brain Injury/Concussion; Evolution
Link ID: 27014 - Posted: 02.01.2020

By Elizabeth Pennisi It’s been a bad couple of weeks for behavioral ecologist Jonathan Pruitt—the holder of one of the prestigious Canada 150 Research Chairs—and it may get a lot worse. What began with questions about data in one of Pruitt’s papers has flared into a social media–fueled scandal in the small field of animal personality research, with dozens of papers on spiders and other invertebrates being scrutinized by scores of students, postdocs, and other co-authors for problematic data. Already, two papers co-authored by Pruitt, now at McMaster University, have been retracted for data anomalies; Biology Letters is expected to expunge a third within days. And the more Pruitt’s co-authors look, the more potential data problems they find. All papers using data collected or curated by Pruitt, a highly productive researcher who specialized in social spiders, are coming under scrutiny and those in his field predict there will be many retractions. The furor has even earned a Twitter hashtag—#PruittData. Yet even one of the researchers who initially probed Pruitt’s data cautions that what has happened remains unclear. “There is no hard evidence that [Pruitt’s] data are fabricated,” says behavioral ecologists Niels Dingemanse of Ludwig Maximilian University of Munich (LMU). © 2019 American Association for the Advancement of Science.

Keyword: Emotions; Evolution
Link ID: 27012 - Posted: 02.01.2020

By Veronique Greenwood You might mistake jewel wings for their colorful cousins, dragonflies. New research shows that these two predators share something more profound than their appearance, however. In a paper published this month in Current Biology, Dr. Gonzalez-Bellido and colleagues reveal that the neural systems behind jewel wings’ vision are shared with dragonflies, with whom they have a common ancestor that lived before the dinosaurs. But over the eons, this brain wiring has adapted itself in different ways in each creature, enabling radically different hunting strategies. For flying creatures, instantaneous, highly accurate vision is crucial to survival. Recent research showed that birds of prey that fly faster also see changes in their field of vision more quickly, demonstrating the link between speed on the wing and speed in the brain. But the group of insects that includes jewel wings and dragonflies took to the air long before birds were even on the evolutionary horizon, and their vision is swifter than any vertebrate’s studied thus far, said Dr. Gonzalez-Bellido. Researchers looking to understand how their vision, flight and hunting abilities are connected are thus particularly interested in the neurons that send visual information to the wings. But recordings made in the lab by Dr. Gonzalez-Bellido and her colleagues confirmed that dragonflies rise up in a straight line to seize unsuspecting insects from below, almost like their prey had stepped on a land mine. This eerie climb may contribute to their startling success rate: Dragonflies snag their prey 97 percent of the time. The difference in hunting behavior may be linked to the placement of the insects’ eyes. Jewel wings’ eyes are on either side of the head, facing forward. The eyes of these dragonflies — the species Sympetrum vulgatum, also known as the vagrant darter — encase the top of the insect’s head in an iridescent dome, with a thin line running down the middle the only visible reminder that they may have once been separate. © 2020 The New York Times Company

Keyword: Vision; Evolution
Link ID: 27008 - Posted: 01.29.2020

Nell Greenfieldboyce Parrots can perform impressive feats of intelligence, and a new study suggests that some of these "feathered apes" may also practice acts of kindness. African grey parrots voluntarily helped a partner get a food reward by giving the other bird a valuable metal token that could be exchanged for a walnut, according to a newly published report in the journal Current Biology. "This was really surprising that they did this so spontaneously and so readily," says Désirée Brucks, a biologist at ETH Zürich in Switzerland who is interested in the evolution of altruism. Children as young as 1 seem highly motivated to help others, and scientists used to think this kind of prosocial behavior was uniquely human. More recent research has explored "helping" behavior in other species, everything from nonhuman primates to rats and bats. To see whether intelligent birds might help out a feathered pal, Brucks and Auguste von Bayern of the Max Planck Institute for Ornithology in Germany tested African grey parrots. They used parrots that had previously been trained to understand that specific tokens, in the form of small metal rings, could be traded for a food treat through an exchange window. In their experiment, this exchange window was covered up and closed on one bird's cage, making it impossible for that bird to trade. The bird had a pile of tokens in its cage but no way to use them. Meanwhile, its neighbor in an adjacent cage had an open exchange window — but no tokens for food. © 2020 npr

Keyword: Emotions; Evolution
Link ID: 26948 - Posted: 01.10.2020

Kristen S. Morrow Human beings used to be defined as “the tool-maker” species. But the uniqueness of this description was challenged in the 1960s when Dr. Jane Goodall discovered that chimpanzees will pick and modify grass stems to use to collect termites. Her observations called into question homo sapiens‘ very place in the world. Since then scientists’ knowledge of animal tool use has expanded exponentially. We now know that monkeys, crows, parrots, pigs and many other animals can use tools, and research on animal tool use changed our understanding of how animals think and learn. Studying animal tooling – defined as the process of using an object to achieve a mechanical outcome on a target – can also provide clues to the mysteries of human evolution. Our human ancestors’ shift to making and using tools is linked to evolutionary changes in hand anatomy, a transition to walking on two rather than four feet and increased brain size. But using found stones as pounding tools doesn’t require any of these advanced evolutionary traits; it likely came about before humans began to manufacture tools. By studying this percussive tool use in monkeys, researchers like my colleagues and I can infer how early human ancestors practiced the same skills before modern hands, posture and brains evolved. Understanding wild animals’ memory, thinking and problem-solving abilities is no easy task. In experimental research where animals are asked to perform a behavior or solve a problem, there should be no distractions – like a predator popping up. But wild animals come and go as they please, over large spaces, and researchers cannot control what is happening around them. © 2010–2020, The Conversation US, Inc.

Keyword: Evolution
Link ID: 26947 - Posted: 01.10.2020

By Veronique Greenwood The cuttlefish hovers in the aquarium, its fins rippling and large, limpid eyes glistening. When a scientist drops a shrimp in, this cousin of the squid and octopus pauses, aims and shoots its tentacles around the prize. There’s just one unusual detail: The diminutive cephalopod is wearing snazzy 3-D glasses. Putting 3-D glasses on a cuttlefish is not the simplest task ever performed in the service of science. “Some individuals will not wear them no matter how much I try,” said Trevor Wardill, a sensory neuroscientist at the University of Minnesota, who with other colleagues managed to gently lift the cephalopods from an aquarium, dab them between the eyes with a bit of glue and some Velcro and fit the creatures with blue-and-red specs. The whimsical eyewear was part of an attempt to tell whether cuttlefish see in 3-D, using the distance between their two eyes to generate depth perception like humans do. It was inspired by research in which praying mantises in 3-D glasses helped answer a similar question. The team’s results, published Wednesday in the journal Science Advances, suggest that, contrary to what scientists believed in the past, cuttlefish really can see in three dimensions. Octopuses and squid, despite being savvy hunters, don’t seem to have 3-D vision like ours. Previous work, more than 50 years ago, had found that one-eyed cuttlefish could still catch prey, suggesting they might be similar. But cuttlefish eyes often focus in concert when they’re hunting, and there is significant overlap in what each eye sees, a promising combination for generating 3-D vision. Dr. Wardill, Rachael Feord, a graduate student at the University of Cambridge, and the team decided to give the glasses a try during visits to the Marine Biological Lab in Woods Hole, Mass. The logic went like this: With each eye covered by a different colored lens, two different-colored versions of a scene, just slightly offset from each other, should pop out into a three-dimensional image. By playing a video on the tank wall of a scuttling pair of shrimp silhouettes, each a different color and separated from each other by varying amounts, the researchers could make a shrimp seem closer to the cuttlefish or farther away. If, that is, the cuttlefish experienced 3-D vision like ours. © 2020 The New York Times Company

Keyword: Vision; Evolution
Link ID: 26945 - Posted: 01.09.2020

By Rodrigo Pérez Ortega Nearly 2600 years ago, a man was beheaded near modern-day York, U.K.—for what reasons, we still don’t know—and his head was quickly buried in the clay-rich mud. When researchers found his skull in 2008, they were startled to find that his brain tissue, which normally rots rapidly after death, had survived for millennia—even maintaining features such as folds and grooves (above). Now, researchers think they know why. Using several molecular techniques to examine the remaining tissue, the researchers figured out that two structural proteins—which act as the “skeletons” of neurons and astrocytes—were more tightly packed in the ancient brain. In a yearlong experiment, they found that these aggregated proteins were also more stable than those in modern-day brains. In fact, the ancient protein clumps may have helped preserve the structure of the soft tissue for ages, the researchers report today in the Journal of the Royal Society Interface. Aggregated proteins are a hallmark of aging and brain diseases like Alzheimer’s. But the team didn’t find any protein clumps typical of those conditions in the ancient brain. The scientists still aren’t sure what made the proteins aggregate, but they suspect it could have something to do with the burial conditions, which appeared to take place as part of a ritual. In the meantime, the new findings could help researchers gather information from proteins of other ancient tissues from which DNA cannot be easily recovered. © 2019 American Association for the Advancement of Science

Keyword: Brain imaging; Glia
Link ID: 26941 - Posted: 01.09.2020

A cousin of the starfish that resides in the coral reefs of the Caribbean and Gulf of Mexico lacks eyes but can still see, according to scientists who studied the creature. Researchers said on Thursday that the red brittle star, called Ophiocoma wendtii, joins a species of sea urchin as the only creatures known to be able to see without having eyes — known as extraocular vision. The red brittle star possesses this exotic capability thanks to light-sensing cells, called photoreceptors, covering its body and pigment cells, called chromatophores, that move during the day to facilitate the animal's dramatic colour change from a deep reddish-brown in daytime to a striped beige at night. Brittle stars, with five radiating arms extending from a central disk, are related to starfish (also called sea stars), sea cucumbers, sea urchins and others in a group of marine invertebrates called echinoderms. They have a nervous system but no brain. Looking for a safe hiding place The red brittle star — which measure up to about 35 centimetres (14 inches) from arm tip to arm tip — lives in bright and complex habitats, with high predation threats from reef fish. It stays hidden during daytime — making the ability to spot a safe place to hide critical — and comes out at night to feed on detritus. Its photoreceptors are surrounded during daytime by chromatophores that narrow the field of the light being detected, making each photoreceptor like the pixel of a computer image that, when combined with other pixels, makes a whole image. The visual system does not work at night, when the chromatophores contract. "If our conclusions about the chromatophores are correct, this is a beautiful example of innovation in evolution," said Lauren Sumner-Rooney, a research fellow at Oxford University Museum of Natural History, who led the study published in the journal Current Biology. ©2020 CBC/Radio-Canada.

Keyword: Vision; Evolution
Link ID: 26929 - Posted: 01.04.2020

By Eva Frederick One day in 2014, primatologist Yuko Hattori was trying to teach a mother chimpanzee in her lab to keep a beat. Hattori would play a repetitive piano note, and the chimp would attempt to tap out the rhythm on a small electronic keyboard in hopes of receiving a tasty piece of apple. Everything went as expected in the experiment room, but in the next room over, something strange was happening. Another chimpanzee, the mother’s son, heard the beat and began to sway his body back and forth, almost as if he were dancing. “I was shocked,” Hattori says. “I was not aware that without any training or reward, a chimpanzee would spontaneously engage with the sound.” Hattori has now published her research showing that chimps respond to sounds, both rhythmic and random, by “dancing.” “This study is very thought-provoking,” says Andrea Ravignani, a cognitive biologist at the Seal Rehabilitation and Research Centre who researches the evolution of rhythm, speech, and music. The work, she says, could shed light on the evolution of dancing in humans. For their the study, Hattori and her colleague Masaki Tomonaga at Kyoto University played 2-minute clips of evenly spaced, repetitive piano tones (heard in the video above) to seven chimpanzees (three males and four females). On hearing the sound, the chimps started to groove, swaying back and forth and sometimes tapping their fingers or their feet to the beat or making howling “singing” sounds, the researchers report today in the Proceedings of the National Academy of Sciences. All of the chimps showed at least a little bit of rhythmic movement, though the males spent much more time moving to the music than females. © 2019 American Association for the Advancement of Science.

Keyword: Evolution; Hearing
Link ID: 26916 - Posted: 12.26.2019