For two squirrel monkeys nicknamed Dalton and Sam, life has gotten a lot more colorful. Researchers used gene therapy to correct the color blindness of the two adult monkeys, giving them the ability to distinguish between red and green for the first time. The fascinating accomplishment suggests that scientists may someday be able to cure other kinds of blindness in humans. And because the treated monkeys were “middle aged”, it challenges the assumption that gene therapies cannot work in adults because their brain connections are too set in their ways to change beneficially [New Scientist].
The field of gene therapy, in which a malfunctioning gene in a patient’s body is replaced with a functional one, fell into disarray one decade ago following the death of an 18-year-old in a clinical trial. But since then scientists have regrouped, using animal studies to probe the technique’s safety. Last year, researchers progressed to the point of safety trials in humans for the treatment of one rare eye condition called Leber congenital amaurosis, and were able to dramatically improve the patients’ sight. Those results were stunning, but they were also achieved in children, whose still-growing brains can rewire themselves on the fly in response to new sources of visual stimuli [Wired.com].
In the new study, published in Nature, the researchers used a type of squirrel monkey in which the males lack a visual pigment called L-opsin. Its absence renders the monkeys color-blind, unable to distinguish reds and green. Most of the females, on the other hand, see in full color. So the scientists got to wondering: what would happen if they gave a boy squirrel monkey the same opsin that girls have [Scientific American]. They used a harmless virus to ferry in the gene that makes opsin, injecting the virus behind the monkeys’ retinas.
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A person can witness an event in real life, see a doctored video of the same event, and then convince themselves that what they saw on the video is what actually happened, according to a recent study that casts doubt on the reliability of eyewitness testimony.
Psychologists set up an experiment where they filmed two people sitting side by side–one experimental subject and one researcher pretending to be a participant–playing a gambling game where they bet phony money on whether or not they could answer multiple choice questions correctly. They were told that the person with the most money at the end would win a prize.
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Meat may be tasty, but many people object to way that chickens, cows, and other animals are treated at so-called “factory farms,” which produce massive amounts of edible flesh. So could animals that have been genetically engineered to not feel pain (or at least not be bothered by the sensation) offer a solution to an ethical dilemma posed by these meat factories?
That’s what one philosopher asked in a paper published in the journal Neuroethics, concluding that we have an ethical duty to consider the option. “If we can’t do away with factory farming, we should at least take steps to minimise the amount of suffering that is caused” [New Scientist] by practices such as de-beaking chickens without anesthesia, says author Adam Shriver. But because pain serves as an important warning sign, these so-called “pain-free” animals would still be able to sense pain–they just wouldn’t be bothered by it. Researchers seek ways to eliminate the suffering caused by pain without tampering with the physical sensation [New Scientist].
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It’s a movie cliche: the moment when the lost traveler intersects a set of footprints, only to realize that the prints where made by his very own boot soles. The hero then realizes, with plunging heart, that he’s been walking in circles while trying to walk a straight course through the featureless expanse. Now a small study has shown that the cliche is true. Without the sun, a compass or a landmark, people trying to follow a straight course through a forest or a desert ended up back where they started [HealthDay News].
In the first experiment, six participants tried to follow a straight course through a forest in Germany, in an area where the land is flat and the trees quickly begin to look alike. The two subjects who walked on a sunny day stayed on a fairly straight course (as tracked by a GPS device), except for the first 15 minutes when the sun was behind the clouds. But the four who walked on an overcast day repeatedly traveled in circles, sometimes crossing their own paths after only 10 minutes. Says lead researcher Jan Souman: “They didn’t really believe when we showed them afterwards…. I think that’s certainly a point to take away, people may feel very confident about the direction where they’re going but it’s not certain” [ABC News].
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Scientists seem to have finally put to rest a longstanding debate over itchiness: Is the urge to itch a sensation that is simply another interpretation of pain, or a separate feeling altogether? It turns out the two stem from different cells and neural pathways, according to a new study in Science.
To find out whether pain and itchiness are separate sensations, scientists injected mice with a neurotoxin. This toxin homed in on and killed cells that contained active versions of GRPR, a gene that is involved in the sensation of itchiness. (The same research group discovered this itch gene in 2007.) Afterward, the mice could no longer respond to any itchy stimuli. They didn’t flinch. They made no effort to scratch. But they did respond to pain just like other mice do [TIME], showing that the gene needed to be active to transmit itchiness, but not pain. It’s just one study, but it provides strong evidence that itchiness and pain are processed by separate neural pathways.
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Wind power may prove to be a promising source of clean energy, but it can also be deadly to bats. Not only can the animals be sliced by the blades of wind turbines, but the sudden drop in air pressure around the turbines can also cause bats’ lungs to explode. An electromagnetic field emitted near the turbines, however, may help bats steer clear of them, according to a new study published in the Public Library of Science One.
Bat casualties near wind turbines have proven to be significant: In 2004, over the course of six weeks, roughly 1,764 and 2,900 bats were killed at two wind farms in Pennsylvania and West Virginia, respectively [LiveScience]. If wind power continues to become increasingly prevalent, so too might the turbines become a growing threat to bat populations. “Given the growing number of wind turbines worldwide, this is going to be an increasing problem, no question about that,” said [co-author] Paul Racey [LiveScience].
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Bats may have a clever way of catching prey, but it turns out the tiger moth has some tricks of its own to avoid becoming a bat’s next meal. According to a study published in Science, the tiger moth disrupts the sound waves the bat uses home in on prey by emitting its own ultrasound blasts.
Researchers knew that the tiger moth emitted ultrasound waves, but they weren’t sure why. Previous studies indicated the moth’s sounds might serve to startle the bats, or warn them that the insects were unpalatable. The new research, however, tested both of these theories. The scientists had so-called big brown bats hunt tiger moths in a chamber fitted with ultrasonic recording equipment and high-speed infrared video. If the moth sound is used to startle bats, then in the chamber the bats should be disrupted on first attack, then learn to ignore the ultrasonic click, the team figured. That didn’t happen. If the moths’ clicks are warnings that the insects taste bad, then the bats should hear the click, bite the moth—and never do so again whenever they hear the sound. That didn’t happen either [National Geographic News].
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A noisy Italian disco may not seem like a conducive location for scientific experiments, but for a couple of researchers investigating hearing and language processing it was perfect. The undercover scientists studied clubbers who were trying to talk while the music was pumping, and found that they showed a decided preference for speaking into each other’s right ears. What’s more, when the researchers approached clubbers with a request for a cigarette, they found the unwitting test subjects were much more likely to comply if the petition was made in the right ear.
Previous lab studies have also suggested that humans tend to have a preference for listening to verbal input with their right ears and that given stimulus in both ears, they’ll privilege the syllables that went into the right ear. Brain scientists hypothesize that the right ear auditory stream receives precedence in the left hemisphere of the brain, where the bulk of linguistic processing is carried out [Wired.com]. Researchers say this bias holds true for both lefties and righties.
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When a person pick up a rake or a croquet mallet or any other tool, their mental image of their body expands subtly, according to a new study. To move our bodies around in space, the brain builds what’s called a “body schema,” a representation of all our various parts. And this so-called schema is frequently updated to keep up with our ever-changing bodies [Scientific American]. This new study, published in Current Biology, found that using a tool for even a brief amount of time caused volunteers to update their body schema, and to consider the tool a part of their bodies.
Lead researcher Alessandro Farnè first asked volunteers to point at and grab wooden blocks with their hands, then had them perform the same motions with a grabber tool, and finally returned to the hands-only gestures. The researchers recorded all of these tasks using a high-resolution three-dimensional motion-tracking system, so that they could compare in detail the movements performed in each task. They found that after using the grabber, the volunteers approached the blocks with slightly lower acceleration and velocity, although their accuracy was not affected. “They behave like their arm is longer,” says Farnè. “They aren’t clumsy, but they are slower and more determined” [Nature News].
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In a rare conservation success, a beautiful butterfly species that was headed for extinction has been brought back from the brink, thanks to careful biological observations of the insect‘s life cycle. The mysterious disappearance of the Large Blue Butterfly across most of northern Europe was originally put down to its popularity among insect collectors [Telegraph]. Then biologist Jeremy Thomas spent six summers in the 1970s studying the very last colony of large blue butterflies in the United Kingdom, and determined that the butterflies were dependent on one species of red ant for their survival–and those ants were losing their habitat.
The butterflies lay their eggs on flowering thyme plants, and the hatched caterpillars fall to the ground and begin to impersonate immature red ants. They secrete chemicals and even make noises that make the red ants believe they are wayward grubs. The ants then mistakenly carry the caterpillars to their underground homes and keep looking after them even though the adopted intruders gobble ant grubs for 10 months before forming a chrysalis and flying away as adult butterflies [Reuters].
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What are fingerprints good for, besides aiding police investigations? That’s the question that biomechanics researcher Roland Ennos recently set out to answer. This notion that human fingerprints (and presumably footprints) evolved because they act like tire or boot tread–increasing the friction against a smooth surface so we don’t slip or drop stuff–is a 100-year-old urban myth that, apparently, had never been put to the test [NPR].
To test the impact of fingerprints, Ennos rigged a machine that measured the amount of friction generated by a fingertip (belonging to study coauthor Peter Warman) when it was pressed against a piece of acrylic glass. Warman gradually increased the pressure, going from a light touch on the glass to a tight grip, but the corresponding friction didn’t increase as much as the researchers expected. Soon they realised that the skin was not behaving like a normal solid, where friction is proportional to the strength of the contact. Instead, it was behaving like rubber, where the friction is proportional to the contact area between the two surfaces [BBC News].
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Scientists have long been impressed with bats’ echolocation calls, the brief bursts of sound that bounce off surrounding objects and allow the bats to navigate in the dark. But now researchers have found a new level of sophistication in those cries. A new study of greater mouse-eared bats proves that bats can distinguish between the calls of different individual bats. Researchers say this could explain how they remain in a group when flying at high speeds in darkness, and how they avoid interference with one another’s echo-location calls [The Guardian].
In the study, published in the journal PLoS Computational Biology, lead researcher Yossi Yovel played the recordings of bat cries back to his test subjects. “Each bat was assigned two others it had to distinguish between,” Dr Yovel explained. “So we trained bat A on a platform, playing a sound from bat B on one side and from bat C on the other. He had crawl to where the ‘correct’ sound was coming from” [BBC News]. For a correct answer, the bat was rewarded with a mealworm.
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Three patients with severe damage to the corneas of their eyes have achieved dramatic improvements in their vision thanks to contact lenses coated with their own stem cells. While the study was extremely small and the results are quite preliminary, the unequivocal improvement seen in the three patients has given doctors hope that the treatment may work for many patients with damaged corneas. Two of the three patients were legally blind in the treated eye; they can now read big letters on the eye chart. The third could read the top few rows of the chart but is now able to pass the vision test for a driving license [The Australian].
The cornea is the transparent layer that covers the eye – but it can lose transparency, damaging sight. In the most serious cases, people can need cornea grafts or transplants. Corneal disease can be caused by genetic disorders, surgery, burns, infections or chemotherapy. In this study, all three patients had damage to the epithelium – the layer of cells covering the front of the cornea [BBC News].
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Using a fancy piece of chemistry equipment to study the chemical composition of wine, European researchers have one-upped the sophisticated palates of wine connoisseurs. The researchers used ultra high resolution mass spectrometry to sort through all the chemical compounds present in wines that had been aged in oak barrels, and found that for each wine, they could determine which French forest the oak was cut from. No other approach – analytical or sensory – has been able to significantly discriminate wines according to the species or the origin of the oak used for the barrels before, they say [Chemistry World].
The findings could prove useful to wine connoisseurs and historians, the researchers said, concluding that their findings produced “chemical representations of the way such noble nectar can shape, on the (tongue) of the wine taster, some of the outlines of the scene of its birth” [AP]. Similar analyses could also be used to detect wine fraud, the researchers noted.
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Specialized cells found only on flower petals have the same basic function as nonslip mats that prevent people from slipping in the shower, a new study has determined. The bumpy cells, called conical cells, help bees come in for a landing on the flower petals and find their footing, so they can get down to the important business of pollination.
Conical cells had been something of a botanical mystery, with most researchers assuming they played a visual role. One hypothesis held that by modifying the spectral properties of the petal, the cells enabled the plant to appear brighter to pollinators [The Scientist]. In the study, will be published in a forthcoming issue of Current Biology, researchers showed that the conical cells’ main function is to provide friction, and that bees can detect them by touch. The first experiment used two kinds white snapdragons that looked identical to both human and bee eyes, but one was a mutant with flat cells instead of conical. The bees initially went to both flower types, but after 20 visits they chose the blossoms with conical cells more than 80 percent of the time.
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