Mental time-travel in birds

Mental time-travel in birds

  10:22:00 AM    Science Lover

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Certain types of birds may track army ant swarms using sophisticated memory and the ability to plan for the future.

White Whiskered Puff bird Credit: Glenn M Duggan FZS

Some tropical birds collect their prey at army ant raids, where massive swarms of ants sweep through the forest and drive out insects. The behaviour of interest is called bivouac checking; it allows these birds to track the cyclical raid activity of army ant colonies.

Army ants have regular alternating periods of high and low raiding activity, and birds visit the ants’ temporary nest sites (bivouacs) to determine which colonies are raiding on a given day.

The new findings published today in the journal Behavioural Ecology, suggest that bivouac checking allows birds to keep track of multiple army ant colonies, keeping account of which colonies are in periods of high-raiding activity while avoiding colonies with low-raiding activity.

Recent research has discovered that birds check army ant bivouacs at the end of the day, after they have fed at the raid. They may use the information about the army ant nest location the next day to find the ants again, thus accessing a past memory (the nest location) to fulfil a future need (bird will be hungry tomorrow), also known as ‘mental time-travel’.

Two of the authors of the study Corina Logan of the University of Cambridge, and Sean O’Donnell of the University of Washington, observed bivouac checking behaviour in Monteverde, Costa Rica.

Mental time-travel consists of two elements: the ability to remember past events and the ability to anticipate and plan for future events. It has traditionally been considered a quality unique to humans. However, ever since Nicola Clayton of the University of Cambridge discovered that scrub jays (a species of large-brained crow) can remember the past and plan for the future, there have been a suite of studies showing evidence of this ability in other species as well. We now know that corvids (birds in the crow family), some primates, and possibly rats have all shown the ability to remember the past and plan for the future.

Corina Logan, said: “We suspect that future planning could be involved in bivouac-checking bird behaviour because the birds were checking bivouacs when they were not hungry, a behaviour that does not make sense until the next morning upon return to the bivouac when the bird finds the ants raiding again and encounters its next meal – a delayed benefit.”

Until recently, it has been difficult to find model systems for studying mental time travel in an ecologically relevant way. “The fact that we might have happened on a whole new system for exploring these capacities is quite exciting,” added Corina Logan.

Provided by University of Cambridge



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Important step in the next generation of computing

Important step in the next generation of computing

  11:56:00 PM    Science Lover

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Scientists have taken one step closer to the next generation of computers. Research from the Cavendish Laboratory, the University of Cambridge's Department of Physics, provides new insight into spintronics, which has been hailed as the successor to the transistor.

Progress in electronics has relied heavily on reducing the size of the transistor to create small, powerful computers. Now spintronics, hailed as the successor to the transistor, looks set to transform the field.

Spintronics, which exploits the electron’s tiny magnetic moment, or ‘spin’, could radically change computing due to its potential of high-speed, high-density and low-power consumption. The new research sheds light on how to make ‘spin’ more efficient.

For the past fifty years, progress in electronics has relied heavily on the downsizing of the transistor through the semiconductor industry in order to provide the technology for the small, powerful computers that are the basis of our modern information society. In a 1965 paper, Intel co-founder Gordon E. Moore described how the number of transistors that could be placed inexpensively on an integrated circuit had doubled every year between 1958 and 1965, predicting that the trend would continue for at least ten more years.

That prediction, now known as Moore’s Law, effectively described a trend that has continued ever since, but the end of that trend—the moment when transistors are as small as atoms, and cannot be shrunk any further—is expected as early as 2015. At the moment, researchers are seeking new concepts of electronics that sustain the growth of computing power.

Spintronics research attempts to develop a spin-based electronic technology that will replace the charge-based technology of semiconductors. Scientists have already begun to develop new spin-based electronics, beginning with the discovery in 1988 of giant magnetoresistance (GMR) effect. The discovery of GMR effect brought about a breakthrough in gigabyte hard disk drives and was also key in the development of portable electronic devices such as the iPod.

While conventional technology relies on harnessing the charge of electrons, the field of spintronics depends instead on the manipulation of electrons’ spin. One of the unique properties in spintronics is that spins can be transferred without the flow of electric charge currents. This is called “spin current” and unlike other concepts of harnessing electrons, the spin current can transfer information without generating heat in electric devices. The major remaining obstacle to a viable spin current technology is the difficulty of creating a volume of spin current large enough to support current and future electronic devices.



However, the new Cambridge researchers in close collaboration with Professor Sergej Demokritov group at the University of Muenster, Germany, have, in part, addressed this issue. In order to create enhanced spin currents, the researchers used the collective motion of spins called spin waves (the wave property of spins). By bringing spin waves into interaction, they have demonstrated a new, more efficient way of generating spin current.

Dr Hidekazu Kurebayashi, from the Microelectronics Group at the Cavendish Laboratory, said: “You can find lots of different waves in nature, and one of the fascinating things is that waves often interact with each other. Likewise, there are a number of different interactions in spin waves. Our idea was to use such spin wave interactions for generating efficient spin currents.”

According to their findings, one of the spin wave interactions (called three-magnon splitting) generates spin current ten times more efficiently than using pre-interacting spin-waves. Additionally, the findings link the two major research fields in spintronics, namely the spin current and the spin wave interaction.

Dr Kurebayashi added: “I am grateful for the collegial and supportive environment at the Cavendish which makes the flexibility I have been afforded in my postdoc research. This allows me freedom to pursue my interest in spintronics outside of my normal research. I feel that Cambridge is the place where you are able to explore your ideas in an intellectually stimulating atmosphere.”

The research was published on Sunday 03 July in the journal Nature Materials.

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Sony Sets Its Sights on Augmented Reality The future of mobile gaming will merge the virtual and real worlds.

Sony Sets Its Sights on Augmented Reality The future of mobile gaming will merge the virtual and real worlds.

  10:14:00 AM    Science Lover

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Sony has demonstrated a new augmented reality system called Smart AR that can be built into the company's future gaming devices.

Credit: Sony Corporation

Augmented reality involves mapping virtual objects onto a view of the real world, usually as seen through the screen of a smart phone. The technology has so far been used to create a handful of dazzling smart-phone apps, but has yet to take off in a big way. However, many believe that mobile gaming could prove to be an ideal platform for the technology. With Smart AR, certain real-world objects could become part of a game when viewed through a device such as the PlayStation Portable. This could allow game characters to appear on a tabletop, perhaps, or to respond to the movement of real objects.

Unlike many augmented reality systems, Smart AR does not use satellite tracking or special markers to figure out where to overlay a virtual object. Instead, it uses object recognition. This means it works where GPS signals are poor or nonexistent, for example, indoors. The markerless system is more difficult to pull off, but it allows many more everyday objects to be used.

"Prototypes of Sony Computer Entertainment's next-generation of portable entertainment systems will be integrated with this technology," says Takayuki Yoshigahara, deputy general manager of Sony's Intelligent Systems Research Laboratory in Tokyo. "SCE is also considering adopting this technology for its software development kit in the future." This would allow games developers to add augmented reality features in the games made for Sony consoles.

Sony has dabbled with the technology before, using two-dimensional barcodes known as CyberCodes as markers for tracking objects.

According to Yoshigahara, Smart AR identifies objects using an approach known as local feature extraction, which means it tries to identify salient parts of the object within the image. The system also tracks the object's movement, and works out its orientation. This is necessary in order to know how the virtual data should be positioned in relation to the object.

Smart AR also builds a rough 3-D map of a room. This is achieved by measuring disparities between different snapshots taken from slightly different perspectives as the camera moves. This allows virtual objects to interact with the environment.

Tobias Hollerer, an associate professor at the University of California, Santa Barbara, says Sony's technology combines several areas of research. "If they do anything new, it is in tracking the entire room," he says.

Edward Rostens, a lecturer at the University of Cambridge and cocreator of an augmented reality system for the iPhone, called Popcode, says getting several different techniques to work together using the limited processing power of a handheld device would be impressive.

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Tiny Creatures: Big Role in Global Carbon Cycle

Tiny Creatures: Big Role in Global Carbon Cycle

  9:55:00 AM    Science Lover

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Two separate research groups are reporting groundbreaking measurements of the fluid flow that surrounds freely swimming microorganisms. Experiments involving two common types of microbes reveal the ways that one creature's motion can affect its neighbors, which in turn can lead to collective motions of microorganism swarms. In addition, the research is helping to clarify how the motions of microscopic swimmers produces large scale stirring that distributes nutrients, oxygen and chemicals in lakes and oceans.

Researchers have mapped the flow field around a swimming Volvox carteri microbe by tracking the movements of tiny tracer particles. The spherical Volvox is swimming towards the top of the image. Streamlines appear as red curves, and the color map corresponds to the fluid velocity. (Credit: K. Drescher, R. E. Goldstein, N. Michel, M. Polin, and I. Tuval, University of Cambridge)

A pair of papers describing the experiments will appear in the Oct. 11 issue of the APS journal Physical Review Letters.

In order to observe the flow that microorganisms produce, researchers at the University of Cambridge tracked the motion of tiny tracer beads suspended in the fluid surrounding the tiny swimmers. They used the technique to study the fluid around two very different types of creatures: a small, blue-green form of algae called Chlamydomonas reinhardtii that swims by paddling with a pair of whip-like flagella, and the larger, spherical alga Volvox carterii that propels itself with thousands of flagella covering its surface.

The tracer beads showed that the two types of organisms generate distinctly different flow patterns, both of which are much more complex than previously assumed. In a related study performed at Haverford College in Pennsylvania, researchers used a high speed camera to track the flow of tracer particles around Chlamydomonas in a thin, two-dimension film of fluid over the course of a single stroke of its flagella.

The studies should help scientists develop new models to predict the fluid motions associated with aquatic microorganisms. The models will provide clearer pictures of the ways microbes mix bodies of water, and potentially offer insights into the role plankton plays in the carbon cycle as it stirs the world's oceans.

David Saintillan (University of Illinois at Urbana Champagne) gives an overview of the microorganism swimming research in a Viewpoint article in the October 11 edition of APS Physics.

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Turning Thoughts into Words A new approach allows more information to be extracted from the brain.

Turning Thoughts into Words A new approach allows more information to be extracted from the brain.

  2:23:00 AM    Science Lover

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Brain-computer interfaces could someday provide a lifeline to "locked-in" patients, who are unable to talk or move but are aware and awake. Many of these patients can communicate by blinking their eyes, but turning blinks into words is time-consuming and exhausting.

Scientists in Utah have now demonstrated a way to determine which of 10 distinct words a person is thinking by recording the electrical activity from the surface of the brain.

Brian interface: The micro electrodes
shown here were used to record brain
signals in order to decode ten words
from a patient’s thoughts.
Credit: Spencer Kellis, University of Utah

The new technique involves training algorithms to recognize specific brain signals picked up by an array of nonpenetrating electrodes placed over the language centers of the brain, says Spencer Kellis, one of the bioengineers who carried out the work at the University of Utah, in Salt Lake City. The approach used is known as electrocorticography (ECoG). The group was able to identify the words "yes," "no," "hot, "cold," "thirsty," "hungry," "hello," "goodbye," "more," and "less" with an accuracy of 48 percent.

"The accuracy definitely needs to be improved," says Kellis. "But we have shown the information is there."

Individual words have been decoded from brain signals in the past using functional magnetic resonance imaging (fMRI), says Eric Leuthardt, director of the Center for Innovation in Neuroscience and Technology at Washington University School of Medicine in St. Louis, Missouri. This is the first time that the feat has been performed using ECoG, a far more practical and portable approach than fMRI, he says.

Working with colleagues Bradley Greger and Paul House, Kellis placed 16 electrodes on the surface of the brain of a patient being treated for epilepsy. The electrodes recorded signals from the facial motor cortex--an area of the brain that controls face muscles during speech--and over the Wernicke's area, part of the cerebral cortex that is linked with language. To train the algorithm, signals were analyzed as the patient was asked to repeatedly utter the 10 words.

ECoG has long been used to locate the source of epileptic seizures in the brain. But electrodes used are typically several hundred microns in size and are positioned centimeters apart, says Kellis. "The brain is doing processing at a much finer spatial scale than is really detectable by these standard clinical electrodes," he says. The Utah team used a new type of microelectrode array developed by PMT Neurosurgical. The electrodes are much smaller--40 microns in size--and are separated by a couple of millimeters.

It's possible to use less invasive techniques, such as electroencephalography (EEG), which places electrodes on the scalp, to enable brain-to-computer communications. Adrian Owen, a senior scientist in the Cognition and Brain Sciences Unit at the University of Cambridge, UK, has shown that EEG signals can be used to allow people in a persistent vegetative state to communicate "yes" and "no."

But with EEG, many of the signals are filtered out by the skull, says Leuthardt. "What's really nice about ECoG is its potential to give us a lot more information," he says.

Decoding 10 words is "very cool," says Owen, but the accuracy will need to improve dramatically, given the patients the technology is aimed at. "I don't think even 60 percent or 70 percent accuracy is going to work for patients who cannot communicate in any other way and where there is no other margin for verification," he says.

Ultimately, the hope is that ECoG will enable much more sophisticated communication. Last year Leuthardt showed that ECoG could be used to decode vowel and consonant sounds--an approach that might eventually be used to reconstruct a much larger number of complete words.

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