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18 | NewScientist | 3 September 2011 YOU will tell the truth. Applying a magnetic field to the brain seems to hamper our ability to tell lies. Lying is thought to involve inhibiting our normal propensity to truth-telling, so Inga Karton’s team at the University of Tartu in Estonia reasoned that dampening brain activity in the dorsolateral prefrontal cortex (DLPFC) – which is involved in cognitive control – might alter the likelihood of lying. The researchers asked 16 volunteers to name the colour of a disc on a computer screen after receiving transcranial magnetic stimulation (TMS) to dampen activity in their DLPFC. They were given the option to lie or answer honestly. The task was then repeated following TMS of the parietal cortex – a part of the brain unassociated with cognitive control. The volunteers gave Ionised gas keeps Milky Way shining WHAT keeps the Milky Way’s lights on? Ionised clouds of gas have been found close enough to home to keep the galaxy ablaze. The Milky Way forms about one sun-sized star per year, a process that requires a constant source of fuel. Ionised clouds could provide this, but had only been glimpsed via the chemical signature they impart on light reaching us from quasars in other galaxies. Now, Christopher Howk and Nicolas Lehner of the University of Notre Dame in Indiana have detected fast-moving clouds of ionised hydrogen in our galaxy. Using the Cosmic Origins Spectrograph aboard the Hubble Space Telescope, the pair observed 27 stars known to be within about 40,000 light years of the sun, well within the galactic disc. Half were obscured by gas clouds, meaning the gas must be inside the Milky Way (Science, DOI: 10.1126/science.1209069). Wrasse and starfish join forces to catch dinner SEA urchins beware: you are under attack from two sides. Wrasse and starfish are both partial to sea urchin, but struggle to catch it on their own. So they give each other a helping hand to tackle their common prey. Ornate wrasse, Thalassoma pavo, like to eat the tube feet of sea urchins, but as the urchins keep their feet buried in the sea bed the wrasse can’t get to them easily. Marthasterias glacialis, a starfish, also likes sea urchin but isn’t always fast enough to catch them. Nicola Galasso of Tuscia University in Viterbo, Italy, and colleagues have found that the two help each other out. HANS LEIJNSE/FOTO NATURA/MINDEN IN BRIEF Magnets might undo web of lies significantly fewer truthful answers after TMS of the left DLPFC – but suppressing the right DLPFC increased the number of true responses (Behavioural Brain Research, DOI: 10.1016/ j.bbr.2011.07.028). “DLPFC seems to be involved in deception, but its exact role remains unclear,” says Bruno Verschuere at the University of Amsterdam in the Netherlands. He says it is difficult to draw firm conclusions from a small sample. When a sea urchin is attacked by a starfish, it uproots itself and moves away. That exposes its tube foot, so a lurking wrasse can sweep in for a meal. The wrasse’s feast disables the sea urchin, allowing the starfish to catch it and finish the job. The two predators don’t seem to be truly cooperating as neither makes a sacrifice for the other. But their actions nevertheless benefit each other. It is further evidence that wrasse are intelligent and can adapt their foraging methods, says Galasso, who presented her research last week at the summer conference of the Association for the Study of Animal Behaviour in St Andrews, UK. She has also found that ornate wrasse have learned to follow scuba divers, as they often break open sea urchins to attract fish. THE coldest stars in the galaxy have come out of hiding, thanks to NASA’s infrared explorer WISE. Over the course of a year, the Wide-field Infrared Survey Explorer found six of these Y dwarfs, a class of chilly brown “almost stars”, predicted but never before seen. The coldest, WISE 1828+2650, has shattered records, at less than 25 °C. “The brown dwarfs we were turning up before this discovery were more like the temperature of your oven,” says WISE team member Davy Kirkpatrick of the California Institute of Technology in Pasadena. The Y dwarfs were found within 40 light years of the sun. Unlike our sun, they are not massive enough to fuse hydrogen. Dwarf stars come in from the cold
