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By Elizabeth Pennisi Cave fish have long fascinated biologists because of their missing eyes and pale skin. Now, one researcher is studying them for another reason: Their behavior may provide clues to the genetic basis of some human psychiatric disorders. Last week at the 23rd International Conference on Subterranean Biology in Fayetteville, Arkansas, he demonstrated how drugs that help people with schizophrenia and autism similarly affect the fish. “I think there is a lot of potential” for these fish to teach us about mental disorders, says David Culver, an evolutionary biologist at American University in Washington, D.C., who was not involved in the study. Culver adds that—like other work on the cause of cave fish blindness—the new research may also have implications for human disease. A decade ago, the lead author on the new study, Masato Yoshizawa, wanted to understand brain evolution by investigating the effects of natural selection on behavior. The Mexican tetra (Astyanax mexicanus), a cave fish with very close surface relatives, seemed an excellent prospect for that work. Because the two populations can interbreed, it’s easier to pin down genes that might be related to the neural defects underlying behavioral differences. Such breeding studies are not possible in humans. The blind cave fish differ from their surface relatives in several notable ways. They don’t have a social structure and they don’t school. Instead, they lead solitary lives—a behavior that makes sense given their lack of natural predators. They also almost never sleep. They are hyperactive, and—unlike other fish—they are attracted to certain vibrations in the water. Finally, they tend to do the same behavior over and over again and seem to have higher anxiety than their surface relatives. © 2016 American Association for the Advancement of Science.
By MOSHE BAR A FRIEND of mine has a bad habit of narrating his experiences as they are taking place. I tease him for being a bystander in his own life. To be fair, we all fail to experience life to the fullest. Typically, our minds are too occupied with thoughts to allow complete immersion even in what is right in front of us. Sometimes, this is O.K. I am happy not to remember passing a long stretch of my daily commute because my mind has wandered and my morning drive can be done on autopilot. But I do not want to disappear from too much of life. Too often we eat meals without tasting them, look at something beautiful without seeing it. An entire exchange with my daughter (please forgive me) can take place without my being there at all. Recently, I discovered how much we overlook, not just about the world, but also about the full potential of our inner life, when our mind is cluttered. In a study published in this month’s Psychological Science, the graduate student Shira Baror and I demonstrate that the capacity for original and creative thinking is markedly stymied by stray thoughts, obsessive ruminations and other forms of “mental load.” Many psychologists assume that the mind, left to its own devices, is inclined to follow a well-worn path of familiar associations. But our findings suggest that innovative thinking, not routine ideation, is our default cognitive mode when our minds are clear. In a series of experiments, we gave participants a free-association task while simultaneously taxing their mental capacity to different degrees. In one experiment, for example, we asked half the participants to keep in mind a string of seven digits, and the other half to remember just two digits. While the participants maintained these strings in working memory, they were given a word (e.g., shoe) and asked to respond as quickly as possible with the first word that came to mind (e.g., sock). © 2016 The New York Times Company
Link ID: 22360 - Posted: 06.25.2016
Annie Murphy Paul Twelve years ago, I tried to drive a stake into the heart of the personality-testing industry. Personality tests are neither valid nor reliable, I argued, and we should stop using them — especially for making decisions that affect the course of people's lives, like workplace hiring and promotion. But if I thought that my book, The Cult of Personality Testing, would lead to change in the world, I was keenly mistaken. Personality tests appear to be more popular than ever. I say "appear" because — today as when I wrote the book — verifiable numbers on the use of such tests are hard to come by. Personality testing is an industry the way astrology or dream analysis is an industry: slippery, often underground, hard to monitor or measure. There are the personality tests administered to job applicants "to determine if you're a good fit for the company;" there are the personality tests imposed on people who are already employed, "in order to facilitate teamwork;" there are the personality tests we take voluntarily, in career counseling offices and on self-improvement retreats and in the back pages of magazines (or, increasingly, online.) I know these tests are popular because after the book was published, most of the people I heard from were personality-test enthusiasts, eager to rebut my critique of the tests that had, they said, changed their lives. © 2016 npr
Link ID: 22359 - Posted: 06.25.2016
By Patrick Monahan The soft, blinking lights of fireflies aren’t just beautiful—they may also play a role in creating new species. A new study shows that using light-up powers for courtship makes species split off from each other at a faster pace, providing some of the clearest evidence yet that the struggle to find mates shapes the diversity of life. The firefly’s glow, like the enormous claws of fiddler crabs and the elaborate dances of manakins, was sculpted by the struggle for sex. Scientists have long thought that this kind of mating-driven natural selection—called “sexual selection”—could make species split into two. Say females in two populations prefer different color patterns in males: Even if the populations have the same needs in every other way, that simple preference could make them split into species with males of separate colors. “A lot of closely related species differ in sexual traits,” says Emily Ellis, an evolutionary biologist at the University of California (UC), Santa Barbara. But actually linking this kind of evolution to species proliferation is a hard idea to test. “So many people have looked at this and found differing results,” she says—possibly because they looked at smaller groups, like birds, rather than across the whole tree of life. That’s where bioluminescence comes in. Many groups of living organisms, from insects to fish to octopuses, emit light, whether to ward off predators, dazzle prey, or attract mates. It’s a trait that has evolved more than 40 times across the animal kingdom, Ellis says. © 2016 American Association for the Advancement of Science.
By Eric Hand That many animals sense and respond to Earth’s magnetic field is no longer in doubt, and people, too, may have a magnetic sense. But how this sixth sense might work remains a mystery. Some researchers say it relies on an iron mineral, magnetite; others invoke a protein in the retina called cryptochrome. Magnetite has turned up in bird beaks and fish noses and even in the human brain, as Joe Kirschvink of the California Institute for Technology in Pasadena reported in 1992, and it is extremely sensitive to magnetic fields. As a result, Kirschvink and other fans say, it can tell an animal not only which way it is heading (compass sense) but also where it is. “A compass cannot explain how a sea turtle can migrate all the way around the ocean and return to the same specific stretch of beach where it started out,” says neurobiologist Kenneth Lohmann of the University of North Carolina, Chapel Hill. A compass sense is enough for an animal to figure out latitude, based on changes in the inclination of magnetic field lines (flat at the equator, plunging into the earth at the poles). But longitude requires detecting subtle variations in field strength from place to place—an extra map or signpost sense that magnetite could supply, Lohmann says. Except in bacteria, however, no one has seen magnetite crystals serving as a magnetic sensor. The crystals could be something else—say, waste products of iron metabolism, or a way for the body to sequester carcinogenic heavy metals. In the early 2000s, scientists found magnetite-bearing cells in the beaks of pigeons. But a follow-up study found that the supposed magnetoreceptors were in fact scavenger immune cells that had nothing to do with the neural system. And because there is no unique stain or marker for magnetite, false sightings are easy to make. © 2016 American Association for the Advancement of Science
Keyword: Pain & Touch
Link ID: 22357 - Posted: 06.24.2016
By Eric Hand Birds do it. Bees do it. But the human subject, standing here in a hoodie—can he do it? Joe Kirschvink is determined to find out. For decades, he has shown how critters across the animal kingdom navigate using magnetoreception, or a sense of Earth’s magnetic field. Now, the geophysicist at the California Institute of Technology (Caltech) in Pasadena is testing humans to see if they too have this subconscious sixth sense. Kirschvink is pretty sure they do. But he has to prove it. He takes out his iPhone and waves it over Keisuke Matsuda, a neuroengineering graduate student from the University of Tokyo. On this day in October, he is Kirschvink’s guinea pig. A magnetometer app on the phone would detect magnetic dust on Matsuda—or any hidden magnets that might foil the experiment. “I want to make sure we don’t have a cheater,” Kirschvink jokes. They are two floors underground at Caltech, in a clean room with magnetically shielded walls. In a corner, a liquid helium pump throbs and hisses, cooling a superconducting instrument that Kirschvink has used to measure tiny magnetic fields in everything from bird beaks to martian meteorites. On a lab bench lie knives—made of ceramic and soaked in acid to eliminate magnetic contamination—with which he has sliced up human brains in search of magnetic particles. Matsuda looks a little nervous, but he will not be going under the knife. With a syringe, a technician injects electrolyte gel onto Matsuda’s scalp through a skullcap studded with electrodes. He is about to be exposed to custom magnetic fields generated by an array of electrical coils, while an electroencephalogram (EEG) machine records his brain waves. © 2016 American Association for the Advancement of Science.
Keyword: Pain & Touch
Link ID: 22356 - Posted: 06.24.2016
By Elahe Izadi It's referred to as the "brain-eating amoeba." Naegleria fowleri resides in warm freshwater, hot springs and poorly maintained swimming pools. When the single-celled organism enters a person's body through the nose, it can cause a deadly infection that leads to destruction of brain tissue. These infections are extremely rare; 138 people have been infected since 1962, according to the Centers for Disease Control and Prevention. But over the weekend, the amoeba claimed another victim when an 18-year-old died from a meningitis infection caused by N. fowleri, said health officials in North Carolina. Lauren Seitz of Westerville, Ohio, died from a suspected case of primary amebic meningoencephalitis (PAM), and officials are investigating whether she contracted the infection while whitewater rafting in Charlotte during a church trip, the Charlotte Observer reported. The N. fowleri infection "resulted in her developing a case of meningitis ... and inflaming of the brain and surrounding tissues, and unfortunately she died of this condition," Mecklenburg County Health Department director Marcus Plescia told reporters Wednesday. Plescia said that, while they were still gathering information from health officials in Ohio, they do know one of the stops Seitz's group made was to the U.S. National Whitewater Center.
Link ID: 22355 - Posted: 06.24.2016
By REUTERS SINGAPORE — Phones or watches may be smart enough to detect sound, light, motion, touch, direction, acceleration and even the weather, but they can't smell. That's created a technology bottleneck that companies have spent more than a decade trying to fill. Most have failed. A powerful portable electronic nose, says Redg Snodgrass, a venture capitalist funding hardware start-ups, would open up new horizons for health, food, personal hygiene and even security. Imagine, he says, being able to analyze what someone has eaten or drunk based on the chemicals they emit; detect disease early via an app; or smell the fear in a potential terrorist. "Smell," he says, "is an important piece" of the puzzle. It's not through lack of trying. Aborted projects and failed companies litter the aroma-sensing landscape. But that's not stopping newcomers from trying. Like Tristan Rousselle's Grenoble-based Aryballe Technologies, which recently showed off a prototype of NeOse, a hand-held device he says will initially detect up to 50 common odors. "It's a risky project. There are simpler things to do in life," he says candidly. The problem, says David Edwards, a chemical engineer at Harvard University, is that unlike light and sound, scent is not energy, but mass. "It's a very different kind of signal," he says. That means each smell requires a different kind of sensor, making devices bulky and limited in what they can do. The aroma of coffee, for example, consists of more than 600 components. France's Alpha MOS was first to build electronic noses for limited industrial use, but its foray into developing a smaller model that would do more has run aground. Within a year of unveiling a prototype for a device that would allow smartphones to detect and analyze smells, the website of its U.S.-based arm Boyd Sense has gone dark. Neither company responded to emails requesting comment. © 2016 The New York Times Company
Keyword: Chemical Senses (Smell & Taste)
Link ID: 22354 - Posted: 06.24.2016
Jon Hamilton Researchers have identified a substance in muscles that helps explain the connection between a fit body and a sharp mind. When muscles work, they release a protein that appears to generate new cells and connections in a part of the brain that is critical to memory, a team reports Thursday in the journal Cell Metabolism. The finding "provides another piece to the puzzle," says Henriette van Praag, an author of the study and an investigator in brain science at the National Institute on Aging. Previous research, she says, had revealed factors in the brain itself that responded to exercise. The discovery came after van Praag and a team of researchers decided to "cast a wide net" in searching for factors that could explain the well-known link between fitness and memory. They began by looking for substances produced by muscle cells in response to exercise. That search turned up cathepsin B, a protein best known for its association with cell death and some diseases. Experiments showed that blood levels of cathepsin B rose in mice that spent a lot of time on their exercise wheels. What's more, as levels of the protein rose, the mice did better on a memory test in which they had to swim to a platform hidden just beneath the surface of a small pool. The team also found evidence that, in mice, cathepsin B was causing the growth of new cells and connections in the hippocampus, an area of the brain that is central to memory. But the researchers needed to know whether the substance worked the same way in other species. So they tested monkeys, and found that exercise did, indeed, raise circulating levels of cathepsin in the blood. © 2016 npr
By BARRY MEIER and ABBY GOODNOUGH A few months ago, Douglas Scott, a property manager in Jacksonville, Fla., was taking large doses of narcotic drugs, or opioids, to deal with the pain of back and spine injuries from two recent car accidents. The pills helped ease his pain, but they also caused him to withdraw from his wife, his two children and social life. “Finally, my wife said, ‘You do something about this or we’re going to have to make some changes around here,’” said Mr. Scott, 43. Today, Mr. Scott is no longer taking narcotics and feels better. Shortly after his wife’s ultimatum, he entered a local clinic where patients are weaned off opioids and spend up to five weeks going through six hours of training each day in alternative pain management techniques such as physical therapy, relaxation exercises and behavior modification. Mr. Scott’s story highlights one patient’s success. Yet it also underscores the difficulties that the Obama administration and public health officials face in reducing the widespread use of painkillers like OxyContin and Percocet. The use and abuse of the drugs has led to a national epidemic of overdose deaths, addiction and poor patient outcomes. In recent months, federal agencies and state health officials have urged doctors to first treat pain without using opioids, and some have announced plans to restrict how many pain pills a doctor can prescribe. But getting the millions of people with chronic pain to turn to alternative treatments is a daunting task, one that must overcome inconsistent insurance coverage as well as some resistance from patients and their doctors, who know the ease and effectiveness of pain medications. “We are all culpable,” said Dr. David Deitz, a former insurance industry executive and a consultant on pain treatment issues. “I don’t care whether you are a doctor, an insurer or a patient.” © 2016 The New York Times Compan
Keyword: Pain & Touch
Link ID: 22352 - Posted: 06.23.2016
by Helen Thompson Young zebra finches (Taeniopygia guttata) learn to sing from a teacher, usually dad. Remembering dad’s tunes may even be hardwired into the birds’ brains. Researchers at the Okinawa Institute of Science and Technology in Japan measured activity in the brains of male juvenile birds listening to recordings of singing adult males, including their fathers. The team focused its efforts on neurons in a part of the brain called the caudomedial nidopallium that’s thought to influence song learning and memory. A subset of neurons in the caudomedial nidopallium lit up in response to songs performed by dad but not those of strangers, the team reports June 21 in Nature Communications. The more baby birds heard songs, the more their neurons responded and the clearer their own songs became. Sleep and a neurotransmitter called GABA influenced this selectivity. The researchers suggest that this particular region of the brain stores song memories as finches learn to sing, and GABA may drive the storage of dad’s songs over others. Researchers played a variety of sounds for young zebra finches: their own song, dad’s song and songs and calls from other adult finches. Over time, their songs became more and more similar to that of their father. |© Society for Science & the Public 2000 - 2016
By Nancy Stearns Bercaw In her memoir “Aliceheimer’s: Alzheimer’s Through the Looking Glass,” Dana Walrath uses drawings and stories to chronicle three years of caregiving for her mother, Alice, who was in the middle stages of Alzheimer’s disease. The experience turned out to be a magical trip down the rabbit hole of memory loss, an outcome that inspired Dr. Walrath, a medical anthropologist who taught at the University of Vermont College of Medicine and who also studied art and writing, to share their tale. Refusing to accept the dominant narrative of Alzheimer’s disease as a horror story, Dr. Walrath used the techniques of graphic medicine to create “Aliceheimer’s,” an 80-page, 35-picture tribute to her mother’s animated mind. Graphic medicine uses text and graphics to, as she writes in the book’s introduction, “let us better understand those who are hurting, feel their stories, and redraw and renegotiate those social boundaries.” We spoke with Dr. Walrath to learn more about graphic medicine, how the book came into being, and what it can teach others about caring for someone with Alzheimer’s disease. Here’s an edited excerpt of our conversation. Q. You say that “Aliceheimer’s” found you, not the other way around. What’s the backstory of your story? A. After a lifetime of mutually abrasive interaction, my mother moved into my home when a lock-down memory-care unit was her only other option. The years of living together not only brought us closure, but it also integrated my disparate career threads. Medical anthropology, creative writing, visual art — who knew they were connected? I sure didn’t. But Alice must have. During dementia, she said to me, “You should quit your job and make art full time.” © 2016 The New York Times Company
Link ID: 22350 - Posted: 06.23.2016
Alison Abbott It isn’t a scam, as neuroscientist Elena Cattaneo had first assumed. A total stranger really has left the prominent Italian, who is also a senator and a relentless campaigner against the misuse of science, his entire fortune to distribute for research. The sum is likely to be upwards of €1.5 million (US$1.7 million). The short, handwritten will of Franco Fiorini, an accountant from the small town of Molinella near Bologna, was officially made public on 21 June. “I’ll never know for sure why he decided to do this,” says Cattaneo, who adds that she has wept with regret that she cannot thank Fiorini. “But it gives a hopeful message that there are some people like Franco who are able to work out on their own the importance of science and research for Italy’s future.” She intends to make the money available for fellowships for young scientists in Italy, where funds for research are notoriously scarce. Cattaneo, who is based at the University of Milan, is no ordinary researcher. In 2013, then-president Giorgio Napolitano appointed her a senator-for-life in recognition of her activities in promoting science. One of her most famous achievements, made with a handful of colleagues, was a successful two-year battle to stop the Stamina Foundation in Brescia from administering unproven stem-cell therapies. Fiorini died on 21 May at the age of 64. A wheelchair user since a bout of childhood polio left him partially paralysed, he had been director of a construction company in Molinella before taking early retirement 15 years ago. © 2016 Macmillan Publishers Limited,
Keyword: Stem Cells
Link ID: 22349 - Posted: 06.23.2016
Laura Sanders Busy nerve cells in the brain are hungry and beckon oxygen-rich blood to replenish themselves. But active nerve cells in newborn mouse brains can’t yet make this request, and their silence leaves them hungry, scientists report June 22 in the Journal of Neuroscience. Instead of being a dismal starvation diet, this lean time may actually spur the brain to develop properly. The new results, though, muddy the interpretation of the brain imaging technique called functional MRI when it is used on infants. Most people assume that all busy nerve cells, or neurons, signal nearby blood vessels to replenish themselves. But there were hints from fMRI studies of young children that their brains don’t always follow this rule. “The newborn brain is doing something weird,” says study coauthor Elizabeth Hillman of Columbia University. That weirdness, she suspected, might be explained by an immature communication system in young brains. To find out, she and her colleagues looked for neuron-blood connections in mice as they grew. “What we’re trying to do is create a road map for what we think you actually should see,” Hillman says. When 7-day-old mice were touched on their hind paws, a small group of neurons in the brain responded instantly, firing off messages in a flurry of activity. Despite this action, no fresh blood arrived, the team found. By 13 days, the nerve cell reaction got bigger, spreading across a wider stretch of the brain. Still the blood didn’t come. But by the time the mice reached adulthood, neural activity prompted an influx of blood. The results show that young mouse brains lack the ability to send blood to busy neurons, a skill that influences how the brain operates (SN: 11/14/15, p. 22). © Society for Science & the Public 2000 - 2016.
Bentley Yoder was born with his brain outside his skull. Doctors said he didn’t have a chance, but he not only survived—he thrived. Now, some seven months later, Bentley has undergone reconstructive surgery to move his brain back into his skull. Bentley’s parents, Sierra and Dustin, both 25, found out something was wrong when they went in for a routine ultrasound at 22 weeks. Still in the womb, he was diagnosed with a rare condition called encephalocele, or cranium bifidum, in which parts of the brain protrude outside of gaps that have formed in the developing skull. The parents were told that their baby likely wouldn’t survive very long after birth, or that if he did he wouldn’t have any brain function; he was simply “incompatible with life.” As Sierra told the Washington Post, “We had no hope whatsoever.” The parents were unwilling to terminate the pregnancy, saying they wanted at least one chance to meet him before saying goodbye. To virtually everyone’s surprise, Bentley came out on his due date, October 31, 2015, kicking and screaming. After the first 36 hours, Sierra and Dustin had to take him home wearing the only onesie they bothered to purchase. Over the course of the next few weeks and months, Bentley continued to march on, save for a staph infection in his lungs. Aside from the large sac containing critical parts of his brain atop his head, Bentley developed normally. He continued to grow, and cried when he was hungry. The doctors were incredulous, and insisted that the growth above his head was just “damaged tissue,” and that “there’s no way it could be functioning,” but Bentley’s behaviors and normal developmental trajectory suggested otherwise.
Keyword: Development of the Brain
Link ID: 22347 - Posted: 06.22.2016
Agata Blaszczak-Boxe, People with higher levels of education may be more likely to develop certain types of brain tumors, a new study from Sweden suggests. Researchers found that women who completed at least three years of university courses were 23 percent more likely to develop a type of cancerous brain tumor called glioma, compared with women who only completed up to nine years of mandatory education and did not go to a university. And men who completed at least three years of university courses were 19 percent more likely to develop the same type of tumor, compared with men who did not go to a university. Though the reasons behind the link are not clear, "one possible explanation is that highly educated people may be more aware of symptoms and seek medical care earlier," and therefore are more likely to be diagnosed, said Amal Khanolkar, a research associate at the Institute of Child Health at the University College Londonand a co-author of the study. [Top 10 Cancer-Fighting Foods] In the study, the researchers looked at data on more than 4.3 million people in Sweden who were a part of the Swedish Total Population Register. The researchers tracked the people for 17 years, beginning in 1993, to see if they developed brain tumors during that time. They also collected information about the people's education levels, income, marital status and occupation. During the 17-year study, 5,735 men and 7,101 women developed brain tumors, according to the findings, published today (June 20) in the Journal of Epidemiology & Community Health. Copyright 2016 LiveScience,
By Vinicius Donisete Goulart The “new world” monkeys of South and Central America range from large muriquis to tiny pygmy marmosets. Some are cute and furry, others bald and bright red, and one even has an extraordinary moustache. Yet, with the exception of owl and howler monkeys, the 130 or so remaining species have one thing in common: A good chunk of the females, and all of the males, are colorblind. This is quite different from “old world” primates, including us Homo sapiens, who are routinely able to see the world in what we humans imagine as full color. In evolutionary terms, colorblindness sounds like a disadvantage, one which should really have been eliminated by natural selection long ago. So how can we explain a continent of the colorblind monkeys? I have long wondered what makes primates in the region colorblind and visually diverse, and how evolutionary forces are acting to maintain this variation. We don’t yet know exactly what kept these seemingly disadvantaged monkeys alive and flourishing—but what is becoming clear is that colorblindness is an adaptation not a defect. The first thing to understand is that what we humans consider “color” is only a small portion of the spectrum. Our “trichromatic” vision is superior to most mammals, who typically share the “dichromatic” vision of new world monkeys and colorblind humans, yet fish, amphibians, reptiles, birds, and even insects are able to see a wider range, even into the UV spectrum. There is a whole world of color out there that humans and our primate cousins are unaware of. What is becoming clear is that color blindness is an adaptation not a defect.
By DONALD G. McNEIL Jr. Global health authorities are trying to get more countries to mandate the use of the “world’s ugliest color” on cigarette packaging to discourage smoking. In 2012, GfK Bluemoon, a market research company under contract to the Australian government, announced that nearly 1,000 smokers had voted that a drab greenish brown known as opaque couché, number 448c in the Pantone color matching system, was the world’s most repulsive color. It was described as looking like death, filth, lung tar or baby excrement. Color aficionados later noted that it was also similar to the hue of the dress worn by the Mona Lisa. Photo Cigarettes on sale in Sydney, New South Wales. Credit Ryan Pierse/Getty Images Australia then mandated “plain packaging” for cigarettes that was actually anything but plain. The opaque couché-colored boxes have vivid pictures of rotted teeth, tongues with tumors and dangerously tiny newborns, along with warnings about smoking’s dangers printed in type larger than the brand names. Australia has been very successful in getting smokers to quit, so health officials in Britain, France and Ireland have announced plans to imitate the packaging. Last month, the European Court of Justice rebuffed legal challenges, by tobacco companies, to the use of shocking images, and India’s Supreme Court ruled in favor of letting them cover 85 percent of packs. A recent study in JAMA Internal Medicine found that these pictures prompt more smokers to at least try to quit, but the American tobacco industry has blocked all attempts to put them on cigarette packs sold in the United States. © 2016 The New York Times Company
Keyword: Drug Abuse
Link ID: 22344 - Posted: 06.22.2016
James Gorman There’s an aura of power around invasive species. How is it that they can sweep in and take over from the locals? Are they more adaptable, tougher? What are their secrets? The great-tailed grackle is a case in point. North America has its own similar species — the common and boat-tailed grackle. But the great-tailed bird, Quiscalus mexicanus, native to Central America, is one of the most invasive species in the United States. The black birds with iridescent feathers were prized by the Aztec emperor Auitzotl, who, by some accounts, relocated some of them from Veracruz to near Mexico City about 500 years ago. Over the past century or so the bird has spread north and its range is still expanding, particularly in the West, where it haunts cattle feed lots and big dairy farms. The birds are also quite happy in urban areas, like Santa Barbara, Calif., where Corina J. Logan captured and later released some grackle for recent experiments. Great-tailed grackles first caught the attention of Dr. Logan, now at Cambridge University, in 2004 when she was doing undergraduate research in Costa Rica. “They’ll actually walk right up and look you in the eye,” she said. “They look like they’re so smart.” Years later, having earned her Ph.D. at Cambridge, she decided to look more closely at them because she was interested in behavioral flexibility. Grackles, for example, might look under rocks at the beach for something to eat, or switch to discarded sandwich wrappers in a city park. © 2016 The New York Times Company
By Sarah Kaplan Some 250 million years ago, when dinosaurs roamed the Earth and early mammals were little more than tiny, fuzzy creatures that scurried around attempting to evade notice, our ancestors evolved a nifty trick. They started to become active at night. They developed sensitive whiskers and an acute sense of hearing. Their circadian rhythms shifted to let them sleep during the day. Most importantly, the composition of their eyes changed — instead of color-sensing cone photoreceptor cells, they gained thousands of light-sensitive rod cells, which allowed them to navigate a landscape lit only by the moon and stars. Mammals may no longer have to hide from the dinosaurs, but we bear the indelible marks of our scrappy, nocturnal past. Unlike every other vertebrate on land and sea, we still have rod-dominated eyes — human retinas, for example, are 95 percent rods, even though we're no longer active at night. "How did that happen? What is the mechanism that made mammals become so different?" asked Anand Swaroop, chief of the Neurobiology Neurodegeneration and Repair Laboratory at the National Eye Institute. He provides some answers to those questions in a study published in the journal Developmental Cell Monday. The findings are interesting from an evolutionary standpoint, he said, but they're also the keys to a medical mystery. If Swaroop and his colleagues can understand how our eyes evolved, perhaps they can fix some of the problems that evolved with them.