Human birth control pills work on gorillas.
Babies are born without knee caps. They don’t appear until the child reaches 2 to 6 years of age.
Butterflies taste with their feet.
In ancient Egypt, priests plucked every hair from their bodies, including their eyebrows and eyelashes.
Leonardo da Vinci invented the scissors.
Off the shore of Brazil, almost 93 miles away from São Paulo downtown, is Ilha da Queimada Grande. The island is untouched by human developers, and for very good reason. Researchers estimate that on the island live between one and five snakes per square meter. The snakes live on the many migratory birds (enough to keep the snake density remarkably high) that use the island as a resting point.
“Between one and five snakes per square meter” might not be so terrible if the snakes were, say, 2 inches long and nonvenomous. The snakes on Queimada Grande, however, are a unique species of pit viper, the golden lancehead. The lancehead genus of snakes is responsible for 90% of Brazilian snakebite-related fatalities. The golden lanceheads that occupy Snake Island grow to well over half a meter long, and they possess a powerful fast-acting poison that melts the flesh around their bites. Golden lanceheads are so dangerous that, with the exception of some scientific outfits, the Brazilian Navy has expressly forbidden anyone from landing on the island.
Locals in the coastal towns near Queimada Grande love to recount two grisly tales of death on the island. In one, a fisherman unwittingly wanders onto the island to pick bananas. Naturally, he is bitten. He manages to return to his boat, where he promptly succumbs to the snake’s venom. He is found some time later on the boat deck in a great pool of blood.
The other story is of the final lighthouse operator and his family. One night, a handful of snakes enter through a window and attack the man, his wife, and their three children. In a desperate gambit to escape, they flee towards their boat, but they are bitten by snakes on branches overhead.
Marcelo Duarte, a biologist who has visited Snake Island over twenty times, says that the locals’ claim of one to five snakes per square meter is an exaggeration, though perhaps not by much. One snake per square meter is more like it. Not that that should ease one’s mind: At one snake per meter, you’re never more than three feet away from death.
Ilha da Queimada Grande, nicknamed Snake Island, is a 430,000-square-metre (43-hectare) island off the coast of the state of São Paulo, Brazil. [1] It is home to an endemic species of Bothrops, the Golden Lancehead Viper (Bothrops insularis), which is one of the most venomous snakes in the world.
The Golden Lancehead is the only species of snake on the island, yet is considered in danger of extinction since it has no other habitat and might be wiped out by wildfire. The viper population is also at risk frominbreeding, effects of which are evident in the population.
A Discovery Channel documentary claims that in some places there are as many as one snake per square meter, while local legend claims there are five snakes to every square meter.[dubious ]
Plans to build a banana plantation on the island fizzled, but this is likely the origin of the island’s name, as in Portuguese, queimada is a name for a slash-and-burn fire (i.e., to clear land for agriculture); so, the island’s name would mean “the island of the big land-clearing fire.” For a long time, the island’s only inhabitant was a lighthouse keeper. Currently, the Brazilian Navy bans civilians from the island, thoughscientists sometimes receive waivers.
Ilha da Queimada Grande.
WATCH AT YOUR OWN RISK!!!
Steel yourself, homeowner, hiker and anyone else tromping about in this gorgeous weather. Snake season is upon us.
Underfoot and overhead, snakes are on the move again. They’re the flash of scales in monkey grass, the dark shadow arrowing across your garden.
But relax. Show some common sense, say the experts, and you can coexist with our legless neighbors. You may even grow to appreciate them.
Atlantans have little to fear from snakes, said Georgia’s chief herpetologist, John Jensen. He wrote the book on snakes — literally — and has some advice for snake-a-phobes.
“If it’s a big snake, nine times out of 10 it’s a rat snake,” he said.
That’s a good snake. Rat snakes are agile, black and like to hang out where humans do — no surprise, considering their main delicacy, rats, also stick close to people. Other good snakes that hang out around these parts: corn snakes and the common king snake. If you see one, relax; it does not want to bite you.
If it’s a small snake? Nine times out of 10, it is not a baby. It’s probably a brown snake, and it’s not likely to get longer than 10-12 inches long. They eat snails, slugs and the occasional earthworm. In all of recorded history, brown snakes have killed no one.
Still, people get shakes over snakes, said Matthew Field. The founder of All Wildlife Control of Roswell, he fields about 300 snake calls yearly. Nearly all the callers, he said, are certain they’ve got a copperhead in their midst.
“Everybody who calls thinks it’s something that’s going to kill them,” he said.
Most of them are mistaken. Water snakes, said Field, are the dominant snake hereabouts.
Field also anticipates getting more calls in the coming weeks. “They’ve been hibernating all winter,” he said. “Now, it’s time to eat and get a girlfriend.”
A word of advice: avoid ivy. Last year, Field captured a “boatload” of copperheads in some Cobb neighborhoods. “You know what they had in common?” he asked. “They were all in ivy.”
Not the one that bit Levi Fisher. He was walking across pine straw in the front yard of his family’s east Cobb home last summer when he stepped in the wrong place.
“He stumbled and fell and started screaming,” recalled his mother, Christina Fisher. “I caught him before he hit the ground.”
As she held the toddler, Fisher saw a movement in the straw — a snake, still coiled. She yelled for her husband. Justin Fisher was at her side in an instant.
“It’s a copperhead,” he said. “I’m calling 911.”
The ambulance driver headed to Children’s Healthcare of Atlanta at Scottish Rite. There, physicians treated the child with antivenin, neutralizing the poison in Levi’s bloodstream. They responded just in time: The venom had traveled halfway to his heart. If it had reached that tiny organ, the venom may have killed Levi.
The child was in the hospital for four days. He had to periodically return to the hospital for three months so specialists could test his blood. “It took that long for the venom to go away,” said Christina Fisher.
She suspects that the snake had been living in their backyard, which had a fine stand of ivy until the Fishers removed it. Its preferred habitat gone, the copperhead found something else.
Since that encounter, she said, the Fishers have removed fallen trees and leaf piles from their rear yard. “There’s no perfect answer,” Christina Fisher said. “I’m sure there are still snakes in our yard.”
You can count on that, said Anthony DeVingo, owner of Ever Green Landscape Management. The lawn care company has been looking after Atlanta yards for 30 years. “In Georgia,” he said, “you’re only about 10 feet away from a snake at any given time.”
But that is no reason to panic, said DeVingo, trained as a gardener. Snakes eat insects, rats and other vermin. Got a nice yard? Thank a snake.
“I am so pro-snake,” said DeVingo, who routinely picks up the crawly creatures and moves them aside when he’s cutting away bushes and other undergrowth. “I love snakes — especially in the garden.”
The takeaway in this brief missive, dear reader? You watch your step, and Mr. Snake will watch his, er, crawl.
Windows 10 is going to be the last major revision of the operating system.
Jerry Nixon, a Microsoft development executive, said in a conference speech this week that Windows 10 would be the “last version” of the dominant desktop software.
His comments were echoed by Microsoft which said it would update Windows in future in an “ongoing manner”.
Instead of new stand-alone versions, Windows 10 would be improved in regular instalments, the firm said.
Mr Nixon made his comments during Microsoft’s Ignite conference held in Chicago this week.
In a statement, Microsoft said Mr Nixon’s comments reflected a change in the way that it made its software.
“Windows will be delivered as a service bringing new innovations and updates in an ongoing manner,” it said, adding that it expected there to be a “long future” for Windows.
The company said it had yet to decide on what to call the operating system beyond Windows 10.
“There will be no Windows 11,” warned Steve Kleynhans, a research vice-president at analyst firm Gartner who monitors Microsoft.
He said Microsoft had in the past deliberately avoided using the name “Windows 9” and instead chose Windows 10 as a way to signify a break with a past which involved successive stand-alone versions of the operating system.
However, he said, working in that way had created many problems for Microsoft and its customers.
“Every three years or so Microsoft would sit down and create ‘the next great OS’,” he said.
“The developers would be locked away and out would pop a product based on what the world wanted three years ago.”
Microsoft also had to spend a huge amount of money and marketing muscle to convince people that they needed this new version, and that it was better than anything that had come before, he explained.
Moving to a situation in which Windows is a constantly updated service will break out of this cycle, and let Microsoft tinker more with the software to test new features and see how customers like them, he added.
Most of the revenue generated by Windows for Microsoft came from sales of new PCs and this was unlikely to be affected by the change, Mr Kleynhans pointed out.
“Overall this is a positive step, but it does have some risks,” he said.
“Microsoft will have to work hard to keep generating updates and new features, he said, adding that questions still remained about how corporate customers would adapt to the change and how Microsoft would provide support.
“It doesn’t mean that Windows is frozen and will never move forward again,” Mr Kleynhans told the BBC.
“Indeed we are about to see the opposite, with the speed of Windows updates shifting into high gear.”
Hunting you down…to deliver that dish soap you ordered
Amazon’s delivery drone dream is very slowly inching toward reality, anda recently published patent gives some insight to the way the service would probably work.
First and foremost, it wouldn’t just be a replacement for UPS with drones just mindlessly dropping packages at your door all the time. Instead, Amazon envisions a system where the drones actually track you via your phone to find an optimal delivery destination. Maybe the office as opposed to home, or a moving target like that boat you totally own, or even 10 feet in front of you on the sidewalk.
That, or to hunt you down during the robot apocalypse.
MCN has finished riding on the world launch of the latest addition to BMW’s S1000 family – the S1000XR, a bike the German manufacturer dubs ‘Adventure Sports’ by blending the ‘DNA’ of its hugely successful 1200GS Adventure bike and the S1000RR superbike.
The S1000XR is one of the most eagerly-awaited bikes of 2015 and on spec alone it’s easy to see why: BMW is already the world’s leading adventure bike manufacturer with its definitive R1200GS remaining a best seller both in the UK and Europe. In fact, BMW not only knows a bit about adventure bikes it can rightly claim to have invented the breed, first with the original R80G/S and more recently with its Adventure versions.
At the same time the Bavarian marque’s S1000RR, now into its third generation, has been, arguably, the world’s leading sports bike since 2011 thanks to its mix of class-leading power and electronics.
So the idea of blending both to create an ‘Adventure Sports’ machine, one with the image, touring comfort and practicality of the GS, but with the sports appeal and dynamism of the S1000RR seems something of a win-win ‘no brainer’. And judging by the interest the resultant bike seems to be creating and reports that the initial UK allocation is already almost sold out, the buying public seems to agree – and that’s without having ridden it.
There are no real surprises or mysteries about how the XR has been created. In simple terms it’s based on the S1000R, the naked, ‘detuned’ (but still 160bhp) version of the 198bhp S1000RR superbike but with a roomier, stronger chassis (for luggage/passengers), longer travel suspension (for that adventure bike posture, styling/bodywork that’s derivative of both RR and GS (so, yes, there are ‘shark gills’ and a ‘beak’ and all sprinkled with BMW’s trademark quality, adjustable ergonomics (different seat heights are available) and class-leading electronic rider aids.
All of that, as promised, is mouth-watering enough. Better still, I can now say having ridden it, is how well all those seemingly disparate elements work together, how thrilling and fast this tall, upright machine is and, simply, how damn brilliant the XR really is.
From the beginning of our test route near Barcelona there was immediately no doubt that the XR is both a proper, adventure-style machine – it’s a tall, substantial bike with bars that brace your arms wide behind a meaty fairing complete with hand-adjustable, two-position screen – but it’s also one with the heart of a snarling beast.
Don’t get me wrong: the XR’s not intimidating. Optional seat heights mean most can get their feet flat, a low-ish CofG and good manageability makes feet-up U-turns a breeze, while that retuned 999cc four pulls smooth and steady from as little as two thou’. If you can the hand guards through the gaps it’s a decent city bike.
Out into the country it’s clear it’s a much better than average commuter or tourer, too. The seat particularly impressed, cosseting and proving all-day comfy; the adjustable screen works OK (although, for some reason, I could only raise it on the move with my right, not left, hand, which brought its own awkwardness), the S1000R-derived clocks, with analogue tacho and conjoined LCD display for everything else, are decent enough and, between 4 and 7000rpm, that motor is a sheer grunt-meister, bounding forward with an immediacy only matched by its calm ease.
But it’s when you thrash and thrape above that where the XR truly comes into its own and almost certainly sets the new standard for this type of machine.
Prod the optional ESA (Electronics Suspension Adjustment) into ‘Dynamic’ to firm up the whole plot (the rest of the time, the ‘Road’ setting gives a plush enough ride), stab down one on the auto-blipper/quickshift-equipped gearlever and give the XR a fistful and it simply lunges towards the horizon like no adventure bike before. At those revs the XR howls like a track bike, gobbles up gears as fast as the quickshifter can feed them (150mph+ is likely) and, simply, takes no prisoners. Plenty of sportsbikes are set to be shamed by the XR, I guarantee.
But best of all is how composed, precise and quick-enough steering the XR is in the bends, too. Our ride was punctuated to a ridiculous, hilarious degree by ravine and coll-clinging curve and hairpin after curve and hairpin, for mile upon mile upon mile. Virtually any other ‘adventure bike’ I can think of would have wavered and wallowed, ultimately toiled and simply tired its rider out. Not so the XR. Sure, ultimately you’re on a high and wide-barred trailie, but it’s one that simply loves to attack turns, remains fabulously composed whatever you throw at it, has true sports brakes, enough electronics for any sports connoisseur and, because of it all, is an absolute hoot.
On this experience, the XR isn’t just a bike for all reasons, I’m struggling to think of any reason why you wouldn’t want one. Prices, TBC, are set to start around £13K for the bog basic that no-one will want, the around 15 for the fully-loaded variants.
Using the Hubble Space Telescope, astronomers have discovered that the immense halo of gas enveloping the Andromeda galaxy is about six times larger and 1,000 times more massive than previously thought.
The dark, nearly invisible halo stretches about a million light-years from its host galaxy, halfway to our own Milky Way galaxy. This finding promises to tell astronomers more about the evolution and structure of majestic giant spirals, one of the most common types of galaxies in the universe.
“Halos are the gaseous atmospheres of galaxies. The properties of these gaseous halos control the rate at which stars form in galaxies according to models of galaxy formation,” explained the lead investigator Nicolas Lehner of the University of Notre Dame, Indiana. The gargantuan halo is estimated to contain half the mass of the stars in the Andromeda galaxy itself, in the form of a hot, diffuse gas. If it could be viewed with the naked eye, the halo would be 100 times the diameter of the full moon in the sky. This is equivalent to the patch of sky covered by two basketballs held at arm’s length.
The Andromeda galaxy lies 2.5 million light-years away and looks like a faint spindle, about 6 times the diameter of the full moon. It is considered a near-twin to the Milky Way galaxy.
Because the gas in Andromeda’s halo is dark, the team looked at bright background objects through the gas and observed how the light changed. This is a bit like looking at a glowing light at the bottom of a pool at night. The ideal background “lights” for such a study are quasars, which are very distant bright cores of active galaxies powered by black holes. The team used 18 quasars residing far behind Andromeda to probe how material is distributed well beyond the visible disk of the galaxy. Their findings were published in the May 4, 2015 edition of the Astrophysical Journal.
Earlier research from Hubble Cosmic Origins Spectrograph (COS)-Halos program studied 44 distant galaxies and found halos like Andromeda’s, but never before has such a massive halo been seen in a neighboring galaxy. Because the previously studied galaxies were much farther away, they appeared much smaller on the sky. Only one quasar could be detected behind each faraway galaxy, providing only one light anchor point to map their halo size and structure. With its close proximity to Earth and its correspondingly large footprint on the sky, Andromeda provides a far more extensive sampling of a lot of background quasars.
“As the light from the quasars travels toward Hubble, the halo’s gas will absorb some of that light and make the quasar appear a little darker in just a very small wavelength range,” explains co-investigator J. Christopher Howk, also of Notre Dame. “By measuring the dip in brightness in that range, we can tell how much gas there is between us and that quasar.”
The scientists used Hubble’s unique capability to study the ultraviolet light from the quasars. Ultraviolet light is absorbed by Earth’s atmosphere, which makes it difficult to observe with a ground-based telescope. The team drew from about 5 years worth of observations stored in the Hubble data archive to conduct this research. Many previous Hubble campaigns have used quasars to study gas much farther away than — but in the general direction of — Andromeda, so a treasure trove of data already existed.
But where did the giant halo come from? Large-scale simulations of galaxies suggest that the halo formed at the same time as the rest of Andromeda. The team also determined that it is enriched in elements much heavier than hydrogen and helium, and the only way to get these heavy elements is from exploding stars called supernovae. The supernovae erupt in Andromeda’s star-filled disk and violently blow these heavier elements far out into space. Over Andromeda’s lifetime, nearly half of all the heavy elements made by its stars have been expelled far beyond the galaxy’s 200,000 light-year diameter stellar disk.
What does this mean for our own galaxy? Because we live inside the Milky Way, scientists cannot determine whether or not such an equally massive and extended halo exists around our galaxy. It’s a case of not being able to see the forest for the trees. If the Milky Way does possess a similarly huge halo, the two galaxies’ halos may be nearly touching already and quiescently merging long before the two massive galaxies collide. Hubble observations indicate that the Andromeda and Milky Way galaxies will merge to form a giant elliptical galaxy beginning about 4 billion years from now.
The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc., in Washington.
Publication: Nicolas Lehner, et al., “Evidence for a Massive, Extended Circumgalactic Medium Around the Andromeda Galaxy,” 2015, ApJ, 804, 79; doi:10.1088/0004-637X/804/2/79
Source: Rob Gutro, NASA’s Goddard Space Flight Center
Image: NASA/STScI
By mapping the radioisotope titanium-44, NASA’s NuStar reveals evidence of an asymmetrical explosion from supernova 1987A and helps to explain the mechanics of SN 1987A and of core-collapse supernovae in general.
NASA’s Nuclear Spectroscopic Telescope Array, or NuSTAR, has found evidence that a massive star exploded in a lopsided fashion, sending ejected material flying in one direction and the core of the star in the other.
The findings offer the best proof yet that star explosions of this type, called Type II or core-collapse supernovae, are inherently asymmetrical, a phenomenon that had been difficult to prove before now.
“Stars are spherical objects, but apparently the process by which they die causes their cores to be turbulent, boiling and sloshing around in the seconds before their demise,” said Steve Boggs of the University of California, Berkeley, lead author of a new study on the findings, appearing in the May 8 issue of Science. “We are learning that this sloshing leads to asymmetrical explosions.”
The supernova remnant in the study, called 1987A, is 166,000 light-years away. Light from the blast that created the remnant lit up skies above Earth in 1987. While other telescopes had found hints that this explosion was not spherical, NuSTAR found the “smoking gun” in the form of a radioisotope called titanium-44.
“Titanium is produced in the very heart of the explosion, so it traces the shape of the engine driving the disassembly of the star,” said Fiona Harrison, the principal investigator of NuSTAR at the California Institute of Technology in Pasadena. “By looking at the shift of the energy of the X-rays coming from titanium, the NuSTAR data revealed that, surprisingly, most of the material is moving away from us.”
Last year, NuSTAR created detailed titanium-44 maps of another supernova remnant, called Cassiopeia A, also finding evidence of an asymmetrical explosion, though not to as great an extent as in 1987A. Together, these results suggest that lopsidedness is at the very root of core-collapse supernova.
When supernova 1987A first lit up our skies decades ago, telescopes around the world had a unique opportunity to watch the event unfold and evolve. Outer, ejected materials lit up first, followed by the innermost materials powered by radioactive isotopes, such as cobalt-56, which decayed into iron-56. In 2012, the European Space Agency’s Integral satellite detected titanium-44 in 1987A. Titanium-44 continues to blaze in the supernova remnant due to its long lifetime of 85 years.
“In some ways, it is as if 1987A is still exploding in front of our eyes,” said Boggs.
NuSTAR brought a new tool to the study of 1987A. Thanks to the observatory’s sharp high-energy X-ray vision, it has made the most precise measurements of titanium-44 yet. This radioactive material is produced at the core of a supernova, so it provides astronomers with a direct probe into the mechanisms of a detonating star.
The NuSTAR spectral data reveal that titanium-44 is moving away from us with a velocity of 1.6 million mph (2.6 million kilometers per hour). That indicates ejected material flung outward in one direction, while the compact core of the supernova, called a neutron star, seems to have kicked off in the opposite direction.
“These explosions are driven by the formation of a compact object, the remaining core of the star, and this seems to be connected to the core blasting one direction, and the ejected material, the other,” said Boggs.
Previous observations have hinted at the lopsided nature of supernova blasts, but it was impossible to confirm. Telescopes like NASA’s Chandra X-ray Observatory, which sees lower-energy X-rays than NuSTAR, had spotted iron that had been heated in the 1987A blast, but it was not clear if the iron was generated in the explosion or just happened to have been in the vicinity.
“Radioactive titanium-44 glows in the X-rays no matter what and is only produced in the explosion,” said Brian Grefenstette, a co-author of the study at Caltech. “This means that we don’t have to worry about how the environment influenced the observations. We are able to directly observe the material ejected in the explosion.”
Future studies by NuSTAR and other telescopes should further illuminate the warped nature of supernovae. Is 1987A particularly askew, or in line with other objects in its class? A decades-old mystery continues to unravel before our eyes.
NuSTAR is a Small Explorer mission led by the California Institute of Technology in Pasadena and managed by NASA’s Jet Propulsion Laboratory, also in Pasadena, for NASA’s Science Mission Directorate in Washington.
Publication: S. E. Boggs, et al., “44Ti gamma-ray emission lines from SN1987A reveal an asymmetric explosion,” Science 8 May 2015: Vol. 348 no. 6235 pp. 670-671; DOI: 10.1126/science.aaa2259
Source: Whitney Clavin, Jet Propulsion Laboratory
Images: ESA/Hubble & NASA; NASA/JPL-Caltech/UC Berkeley
Using optogenetics, neuroscientists from MIT have provided the first evidence that directly links FD neurons to face-discrimination in primates — specifically, differentiating between males and females.
How do primates, including humans, tell faces apart? Scientists have long attributed this ability to so-called “face-detector” (FD) neurons, thought to be responsible for distinguishing faces, among other objects. But no direct evidence has supported this claim.
Working with macaque monkeys trained to correctly identify images of male or female faces, the researchers used a light-sensitive protein to suppress subregions of FD neurons in the inferior temporal (IT) cortex, a visual information-processing region. In suppressing the neurons, the researchers observed a small yet significant impairment in the animals’ ability to properly identify genders.
“If these face-detector neurons are participating in face-discriminating behavior — in telling gender of faces apart — then, if we knock them down, the behavior should take a hit,” says Arash Afraz, a research scientist at MIT’s McGovern Institute for Brain Research and lead author of a paper describing the study in the Proceedings of the National Academy of Sciences.
This experiment, Afraz says, marks a step forward in understanding the links between specific neurons and primate behavior. “You actually have to perturb the activation of that neuron and see if you can affect behavior,” he says. “If that happens, it means these neurons are part of the causal chain for that particular behavior.”
By providing a closer look at primate object-recognition, Afraz adds, the study could also aid in developing visual prostheses that may require direct wiring with the IT cortex. More broadly, understanding the light level needed for optogenetic neural silencing could also aid in developing implantable treatments for patients with temporal lobe epilepsy. “We could have devices implanted in the cortex that automatically turn on when the epilepsy attack starts, and silence the cortex with light,” Afraz says.
Co-authors of the study are James DiCarlo, a professor of neuroscience and head of MIT’s Department of Brain and Cognitive Sciences, and Ed Boyden, an associate professor of biological engineering and brain and cognitive sciences whose group developed the optogenetics tools used in the study.
Knocking down neurons
In the 1980s, scientists first hypothesized FD neurons, with studies that recorded spikes in neural activity in response to images of faces. “But we [never had] a clear mechanistic connection between the activation of these neurons and face discrimination, as opposed to face detection,” Afraz says.
For the PNAS paper, the MIT researchers trained two monkeys to identify images of gendered faces with about 90 percent accuracy. To do so, they displayed images of male and female faces with varying features slightly to the left or right of a middle fixation point of a screen. Then, they displayed two dots on the top and bottom of the screen; the monkeys looked at the top dot if the face was female, and at the bottom dot if it was male.
The researchers then measured neural activity in the IT cortex of the monkeys, locating a number of subregions where FD neurons were most and least concentrated. Next, they injected high- and low-FD subregions with a virally delivered protein engineered by Boyden’s group, called ArchT, which subdues neural activity in the presence of light.
After a month, the monkeys viewed 1,600 grayscale images of male and female faces, during 40 separate sessions, while the researchers delivered random pulses of green light to the ArchT-treated areas. Suppressing only 1 millimeter of high-FD subregions — not low-FD subregions — impaired the animals’ ability to correctly identify gendered faces by, on average, about 2 percent, the researchers found.
Linking tiny clusters of neurons with the perceptual ability to identify genders suggests those neurons are responsible for processing gendered faces, Afraz says. “Wherever a signal is encoded more explicitly in the brain, that part seems to contribute more to the behavior directly,” Afraz explains. “If we know the information of a face’s gender is encoded more explicitly in a small bit of cortex, knocking down that bit of cortex takes a bigger toll on behavior.”
New avenue of discovery
While his lab has researched visual processing for 20 years, DiCarlo notes that “this collaboration with Boyden — who develops cutting-edge tools — is what opened the door to this significant advance, and to an entire new avenue of discovery.”
In particular, as one of the first documented uses of optogenetics to induce behavioral changes in primates, the study also demonstrates the potential for using it to study vision and behaviors in primates, Boyden says. In contrast to traditional neural-suppression methods, for instance, optogenetics tools can zero in on tiny clusters of neurons for brief moments, which can better pinpoint specific neurons as drivers of behavior.
“We’re getting at the actual circuitry of the brain and the exact neurons that are involved in discriminating [between faces],” Boyden says. “These tools offer higher temporal and spatial resolution than any other neural perturbation method.”
Robert Newsome, a professor of neurobiology at Stanford University, says the study “addresses a fascinating problem in systems neuroscience … in a set of very challenging experiments” that utilize both optogenetics- and pharmaceutical-suppression techniques.
“This,” he adds, “is a powerful demonstration that face-detecting neurons mediate the perceptual ability to discriminate among faces — a very cool result.”
The study was funded by the National Institutes of Health.
Publication: Arash Afraz, et al., “Optogenetic and pharmacological suppression of spatial clusters of face neurons reveal their causal role in face gender discrimination,” PNAS, 2015; doi: 10.1073/pnas.142332811
Source: Rob Matheson, MIT News
Image: iStock (edited by MIT News)
Bali,Indonesia
"tkmechaero" 