Spinal injuries often leave people with paralysed limbs, as commands from their brains can no longer reach the muscles in their arms. So why not bypass the spine entirely? A team from Northwestern University has used a brain decoder to give monkeys control over their temporarily anaesthetised arms. The decoder deciphers the activity in the monkey’s motor cortex (the part of the brain that controls movements), and electrodes in the monkey’s arm stimulate its muscles in the right way. Even though it can’t feel its arm, it can grab a ball using this electronic middle-man.
I covered this research in more detail at The Scientist, including some comments from a few skeptical scientists, who are concerned about the technique’s limitations.
Here’s the fourth piece from my new BBC column
In The Truth Machine, a science-fiction novel published in 1996, scientists invent a device that can detect lies with perfect accuracy. It abolishes crime, changes the world, and generally saves humanity from self-destruction. Which is nice.
Could such a machine ever be a reality? Not if our current technology is anything to go by. The polygraph has been around for almost a century, with wired-up offenders and twitching needles becoming a staple of criminal investigations. But there is no solid evidence that the signs it looks for – faster heart rates, shallower breaths and moist skin – can accurately indicate whether someone is telling a lie. Underpinned by fluffy theory and backed by a weak and stagnant evidence base, this lie-detection device is unlikely to get any better.
Inside the brain
Abandoning the polygraph, some scientists have turned to brain scanners. Two technologies have dominated the field. The first uses electronic sensors on a person’s scalp to measure an electrical signal, or “brainwave”, called the P300, which appears when we recognise something. By looking for this signal, you could potentially tell if someone is hiding knowledge about something they are already familiar with, like a murder weapon. This is certainly useful, but it is a long way from an all-purpose lie-detection method, and two of the key figures in the field have been arguing about how effective this is for many years.
The second technique is functional magnetic resonance imaging (fMRI), affectionately known as blobology for the colourful pictures it produces. It shows the location of firing neurons in an indirect manner, by tracking the blood flow that supplies them with nutrients and oxygen. Several fMRI studies have shown that some parts of the brain are consistently more active when people tell untruths rather than truths, particularly areas at the very front that help us to suppress unwanted actions. Successful lying, it seems, is mainly about repressing the urge to be honest.
Here’s the third piece from my new BBC column
A 46 year-old man called Miikka spotted a simple spelling mistake. A group of scientists had misspelled his name as Mika. He told them as much, and they responded with delight. Why? It was the clearest evidence yet that Miikka, who had been blind for many years, might be able to see again.
This miracle is thanks to a pioneering chip implanted in his retina. Just as cochlear implants have restored hearing to people once considered deaf, devices like this are being developed that can restore sight to the blind.
Miikka suffers from a particular form of blindness called retinitis pigmentosa, an inherited disease that gradually destroys the light-detecting cells of the retina. As the cells die, a person’s field of view begins to collapse from the edges. Miikka’s case was so advanced that he could only sense the direction of a bright light, and he needed a cane to get around.
Thomas Libby filmed rainbow agamas – a beautiful species with the no-frills scientific name of Agama agama – as they leapt from a horizontal platform onto a vertical wall. Before they jumped, they first had to vault onto a small platform. If the platform was covered in sandpaper, which provided a good grip, the agama could angle its body perfectly. In slow motion, it looks like an arrow, launching from platform to wall in a smooth arc (below, left)
If the platform was covered in a slippery piece of card, the agama lost its footing and it leapt at the wrong angle. It ought to have face-planted into the wall, but Libby found that it used its long, slender tail to correct itself (below, right). If its nose was pointing down, the agama could tilt it back up by swinging its tail upwards.
A group of computer gamers are making habit of outshining scientists at their own game. Most of them have no scientific background, but they have a track record of cracking tough scientific puzzles, including at least one that went unsolved for over a decade. They are the Foldit players, and for their latest trick, they’ve shown that they can not only solve hard problems, but also create problem-solving tools that outperform the best in the business.
Foldit is an online multiplayer game, created by Seth Cooper and Zoran Popovic at the University of Washington. It’s designed to tap the collecting problem-solving skills of thousands of people, by reframing scientific problems in a way that even a complete novice can tackle.
In the game, players work together to decipher the structures of proteins. These molecules are feats of biological origami; they consist of long chains of amino acids that scrunch up into complicated three-dimensional shapes. Scientists need to resolve these shapes to understand how the proteins work, and the usual methods involve bouncing X-rays off purified crystals (which is difficult) or using predictive software (which is imperfect). Cooper and Popovic went down a third route: they got gamers to play their way to a solution.
This is where we are now: at Duke University, a monkey controls a virtual arm using only its thoughts. Miguel Nicolelis had fitted the animal with a headset of electrodes that translates its brain activity into movements. It can grab virtual objects without using its arms. It can also feel the objects without its hands, because the headset stimulates its brain to create the sense of different textures. Monkey think, monkey do, monkey feel – all without moving a muscle.
And this is where Nicolelis wants to be in three years: a young quadriplegic Brazilian man strolls confidently into a massive stadium. He controls his four prosthetic limbs with his thoughts, and they in turn send tactile information straight to his brain. The technology melds so fluidly with his mind that he confidently runs up and delivers the opening kick of the 2014 World Cup.
This sounds like a far-fetched dream, but Nicolelis – a big soccer fan – is talking to the Brazilian government to make it a reality. He has created an international consortium called the Walk Again Project, consisting of non-profit research institutions in the United States, Brazil, Germany and Switzerland. Their goal is to create a “high performance brain-controlled prosthetic device that enables patients to finally leave the wheelchair behind.”
These small studs, arranged in grids and honeycombs, look completely unnatural. If the image was life-sized, you might think that they’re part of a bizarre children’s toy. If they had been photographed from far away, they might be buildings in an alien city. But they are neither. They have been intensely magnified; a thousand of them could fit across a human hair. They studs are part of the skin of a tiny insect-like creature called a springtail. They’re the secret behind its incredible waterproof shell.
There are more than 7,000 species of springtail, and they’re among the most abundant animals that you can still see with the naked eye. Most are no bigger than a pinhead. They crawl through soil and leaf litter on six legs, and they leap about using a spring-like tail held under their body. Once thought to be insects, they are now classified in a separate but closely related group.
Unlike insects, which breathe using tubes called trachea, the springtails breathe directly through their skin. And this means that if they get wet, they suffocate. This might be a problem for creatures that move about the damp forest floor, but springtails have evolved an extraordinary skin that repels water and a variety of other liquids. Ralf Helbig from the Leibniz Institute of Polymer Research in Dresden examined the skins of 37 different springtails, and discovered that they have three tricks for keeping dry.
Twitter is either an indispensible professional and personal tool, or the downfall of humanity, depending on who you believe. But to Scott Golder and Michael Macy from Cornell University, it is something more: an unparalleled source of data. The duo has used the popular social networking site to eavesdrop upon the world’s moods, as they rise and fall throughout the day and across the week. By analysing half a billion tweets from 2.4 million people in 84 different countries, they turned Twitter into a giant global mood ring.
They found that, on average, people wake up in a good mood, which falls away over the course of the day. Positive feelings peak early in the morning and again nearer midnight, while negative feelings peak between 9pm and 3am. Unsurprisingly, people get happier as the week goes on. They’re most positive on Saturdays and Sundays and they tend to lie in for an extra two hours, as shown by the delayed peak in their positive feelings. The United Arab Emirates provide an interesting exception. There, people work from Sunday to Thursday, and their tweets are most positive on Friday and Saturday.
I’ve got a new piece in Nature News about a cool new technique that uses glowing bacteria to send encrypted messages. There’s lots to like about this: they call the technique SPAM, they reference Mission Impossible in the paper, and the whole thing is actually funded by DARPA (the US Defense Advanced Research Projects Agency).
But most importantly of all, it allowed me to get Godwin’s Law into Nature (3rd paragraph from bottom). Thanks Meredith L Patterson!
From the piece (do read the full one):
For millennia, people have written secret messages in invisible ink, which could only be read under certain lights or after developing with certain chemicals. Now, scientists have come up with a way of encoding messages in the colours of glowing bacteria.
The technique, dubbed steganography by printed arrays of microbes (SPAM), creates messages that can be sent through the post, unlocked with antibiotics and deciphered using simple equipment.
Manuel Palacios, a chemist at Tufts University in Medford Massachusetts, [encrypted] messages using seven strains of Escherichia coli bacteria. Each one was engineered to produce a different fluorescent protein, which glows in a different colour under the right light.
Colonies of bacteria are grown in rows of paired spots, every combination of two colours corresponding to a different letter, digit or symbol. For example, two yellow spots signify a ‘t’, whereas an orange and a green spot denote a ‘d’. Once grown, the pattern of colonies is imprinted onto a nitrocellulose sheet, which is posted in an envelope. The recipient can use the sheet to regrow the bacteria in the same pattern and decipher the message.
Reference: Palacios, Benito-Pena, Manesse, Mazzeo, LaFratta, Whitesides & Walt. 2011. InfoBiology by printed arrays of microorganism colonies for timed and on-demand release of messages. PNAS http://dx.doi.org/10.1073/pnas.1109554108
Tak-Sing Wong from Harvard University has created a synthetic material so slippery that it makes a duck’s back look like a sponge. It is “omniphobic” – it repels everything. All manner of liquids, from water to blood to crude oil, roll straight off it. Ice cannot form on it. It even heals itself when damaged. It’s an extraordinary material and it was inspired by the lips of a flesh-eating plant.