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Unwanted Memories Might Be Erasable Without Harming Other Brain Functions

2008-12-26T17:23:56Z

Researchers have found a molecule that stores complex, high-quality memories, in a discovery that may one day lead to the ability to erase debilitating painful memories and addictions from the brain. (Credit: iStockphoto/Sebastian Kaulitzki))

In a discovery that may one day lead to the ability to erase debilitating painful memories and addictions from the brain, researchers at SUNY Downstate Medical Center have found that a molecule known to preserve memories � PKMzeta � specifically stores complex, high-quality memories that provide detailed information about an animal's location, fears, and actions, but does not control the ability to process or express this information. This finding suggests that PKMzeta erasure that is designed to target specific debilitating memories could be effective against the offending memory while sparing the computational function of brain.

The findings are detailed in the December edition of PLoS Biology in a paper titled, "PKMzeta Maintains Spatial, Instrumental, and Classically Conditioned Long-Term Memories." The paper is authored by Andre A. Fenton, PhD, associate professor of physiology and pharmacology, Todd C. Sacktor, MD, professor of physiology and pharmacology and of neurology, and Peter Serrano, PhD, research assistant professor of physiology and pharmacology, at SUNY Downstate, as well as by colleagues at other institutions in Michigan, New York, Wisconsin, and the Czech Republic.

Dr. Fenton said, "The work published in PLoS reveals that PKMzeta is a general storage mechanism for different types of memory content but, fortunately, that PKMzeta stores only high-quality memories, the kind that provide detailed information rather than general abilities."

"If further work confirms this view we can expect to one day see therapies based on PKMzeta memory erasure," Dr. Fenton suggests. "Negative memory erasing not only could help people forget painful experiences, but might be useful in treating depression, general anxiety, phobias, post-traumatic stress, and addictions," he adds.

Dr. Sacktor said the research "shows that PKMzeta is fundamental for storing many different forms of memory, which previously has been viewed as potentially mediated by distinct mechanisms."

Young Active Star Resembles The Sun When It Was Young

2008-12-24T15:51:16Z

Artist's illustration of CoRoT satellite (Credit: Copyright CNES 2006, by D. Ducros; courtesy of INAF-Italian National Institute for Astrophysics)

An investigation on the intrinsic variations of the star has been carried out by another international team, led by astronomers of the Italian National Institute for Astrophysics (INAF) at Catania Astrophysical Observatory with the support of the Italian Space Agency (ASI).

With its very high photometric accuracy and the long duration of continuous observations, CoRoT has been able for the first time to measure the variations of the intensity of the star and follow it for more than 150 days. These unique data show flux variations of about 6 percent, at least 20 times greater than those of the present Sun, with a periodic modulation of 4.5 days. They are produced by spots, analogous to sunspots, but having a correspondingly larger area, that evolve continuously as the star rotates.

CoRoT observations revealed an unexpected phenomenon: the spotted area oscillates with a mini-cycle of only 29 days. In the Sun, such mini-cycles have sometimes been observed close to the maxima of the main 11-year cycle, with a period of about 150 days. They have been accompanied by corresponding modulations in the frequency and intensity of solar flares, whose energetic radiation impacted upon the planets. The shorter period observed in CoRoT-Exo-2a may be due to its faster rotation or the perturbations induced by the close giant planet, orbiting at a distance of only 4.2 million kilometers from the star, i.e., only 3 percent the distance between the Sun and the Earth.

Our Sun, during the evolutionary stage corresponding to that of CoRoT-Exo-2a, was shining on the Earth when the processes that would have led to the appearance of life had just begun. The presence of an intense magnetic activity on the young Sun and its light variability certainly affected those processes. The study of Sun-like stars with the CoRoT satellite and other spaceborne or ground-based telescopes will contribute to our understanding of the influence of stars on their planets during those crucial phases of their evolution. In the specific case of CoRoTExo-2a, additionally interesting results are expected from future observations, also with ground-based telescopes, to confirm the possible effect of the giant planet on stellar magnetic activity.

Chocolate, Wine And Tea Improve Brain Performance

2008-12-24T15:49:53Z

Chocolate, wine and tea enhance cognitive performance. (Credit: iStockphoto/Silvia Jansen)

The team from Oxford�s Department of Physiology, Anatomy and Genetics and Norway examined the relation between cognitive performance and the intake of three common foodstuffs that contain flavonoids (chocolate, wine, and tea) in 2,031 older people (aged between 70 and 74).

Participants filled in information about their habitual food intake and underwent a battery of cognitive tests.Those who consumed chocolate, wine, or tea had significantly better mean test scores and lower prevalence of poor cognitive performance than those who did not. The team reported their findings in the Journal of Nutrition.

The role of micronutrients in age-related cognitive decline is being increasingly studied. Fruits and beverages such as tea, red wine, cocoa, and coffee are major dietary sources of polyphenols, micronutrients found in plant-derived foods. The largest subclass of dietary polyphenols is flavonoids, and it has been reported in the past that those who consume lots of flavonoids have a lower incidence of dementia.

The latest findings seem to support the theory, although the researchers caution that more research would be needed to prove that it was flavonoids, rather than some other aspect of the foods studied, that made the difference.The effect was most pronounced for wine.

However, say the researchers, those overdoing it at Christmas should note that while moderate alcohol consumption is associated with better cognitive function and reduced risk of Alzheimer�s disease and dementia, heavy alcohol intake could be one of many causes of dementia � as well as a host of other health problems.

Artificial Human Bone Marrow Created In A Test Tube

2008-12-23T12:20:30Z

Researchers have created artificial bone marrow that can continuously make red and white blood cells. (Credit: iStockphoto/Bogdan Pop)

This development could lead to simpler pharmaceutical drug testing, closer study of immune system defects and a continuous supply of blood for transfusions.

The substance grows on a 3-D scaffold that mimics the tissues supporting bone marrow in the body, said Nicholas Kotov, a professor in the U-M departments of Chemical Engineering; Materials Science and Engineering; and Biomedical Engineering.

The marrow is not made to be implanted in the body, like most 3-D biomedical scaffolds. It is designed to function in a test tube.

Kotov, principal investigator, is an author of a paper about the research currently published online in the journal Biomaterials. Joan Nichols, professor from the University of Texas Medical Branch, collaborated on many aspects of the project.

"This is the first successful artificial bone marrow," Kotov said. "It has two of the essential functions of bone marrow. It can replicate blood stem cells and produce B cells. The latter are the key immune cells producing antibodies that are important to fighting many diseases."

Blood stem cells give rise to blood as well as several other types of cells. B cells, a type of white blood cell, battle colds, bacterial infections, and other foreign or abnormal cells including some cancers.

Cancer-fighting chemotherapy drugs can strongly suppress bone marrow function, leaving the body more susceptible to infection. The new artificial marrow could allow researchers to test how a new drug at certain potencies would affect bone marrow function, Kotov said. This could assist in drug development and catch severe side effects before human drug trials.

Bone marrow is a complicated organ to replicate, Kotov said. Vital to the success of this new development is the three-dimensional scaffold on which the artificial marrow grows. This lattice had to have a high number of precisely-sized pores to stimulate cellular interaction.

The scaffolds are made out of a transparent polymer that nutrients can easily pass through. To create the scaffolds, scientists molded the polymer with tiny spheres ordered like billiard balls. Then, they dissolved the spheres to leave the perfect geometry of pores in the scaffold.

The scaffolds were then seeded with bone marrow stromal cells and osteoblasts, another type of bone marrow cell.

"The geometrical perfection of the polymer molded by spheres is very essential for reproducibility of the drug tests and evaluation of potential drug candidates," Kotov said. "The scaffold for this work had to be designed from scratch closely mimicking real bone marrow because there are no suitable commercially products.

"Certain stem cells that are essential for immunity and blood production are able to grow, divide and differentiate efficiently in these scaffolds due to the close similarity of the pores in the scaffold and the pores in actual bone marrow."

The researchers demonstrated that the artificial marrow gives a human-like response to an infectious New Caledonia/99/H1N1 flu virus. This is believed to be a first.

To determine whether the substance behaves like real bone marrow, the scientists implanted it in mice with immune deficiencies. The mice produced human immune cells and blood vessels grew through the substance.

Earth Not Center Of The Universe, Surrounded By 'Dark Energy'

2008-12-23T12:19:02Z

Canadian cosmologists have concluded that Earth's location in the Universe is utterly unremarkable, despite recent theories that propose toppling a foundation of modern cosmology. (Credit: iStockphoto/Andrey Prokhorov)

Polish astronomer Nicolaus Copernicus's 1543 book, On the Revolutions of the Heavenly Spheres, moved Earth from being the centre of the Universe to just another planet orbiting the Sun. Since then, astronomers have extended the idea and formed the Copernican Principle, which says that our place in the Universe as a whole is completely ordinary. Although the Copernican Principle has become a pillar of modern cosmology, finding conclusive evidence that our neighbourhood of the Universe really isn't special has proven difficult.

In 1998, studies of distant explosions called "type Ia supernovae" indicated that the expansion of the Universe is accelerating, an observation attributed to the repulsive force of a mysterious "dark energy." However, some scientists put forward an alternate theory: They proposed that the Earth was near the centre of a giant "bubble," or "void," mostly empty of matter, and strongly violating the Copernican Principle. If this were the case, gravity would create the illusion of acceleration, mimicking the effect of dark energy on the supernova observations.

Now some advanced analysis and modeling performed by UBC post-doctoral fellows Jim Zibin and Adam Moss and Astronomy Prof. Douglas Scott is showing that this alternate "void theory" just doesn't add up.

The researchers used data from the Wilkinson Microwave Anisotropy Probe satellite, which includes members from UBC on its international team, as well as data from various ground-based instruments and surveys.

"We tested void models against the latest data, including subtle features in the cosmic microwave background radiation � the afterglow of the Big Bang � and ripples in the large-scale distribution of matter," says Zibin. "We found that void models do a very poor job of explaining the combination of these data."

The team's calculations instead solidify the conventional view that an enigmatic dark energy fills the cosmos and is responsible for the acceleration of the Universe. "Recent advances in data collection have brought us to the era of precision cosmology," says Zibin. "Void models are terrible at explaining the new data, but the standard dark energy model works very well.

"Since we can only observe the Universe from Earth, it's really hard to determine if we're in a 'special place,'" says Zibin. "But we've now learned that our location is much more ordinary than the strange dark energy that fills the Universe."

LEDs And Smart Lighting Could Save Trillions Of Dollars, Spark Global Innovation

2008-12-21T13:53:18Z

If all of the world's light bulbs were replaced with energy-efficient LEDs for a period of 10 years, researchers say it would reduce global oil consumption by 962 million barrels, reduce the need for 280 global power plants, reduce carbon dioxide emissions by 10.68 gigatons, and ultimately result in financial savings of $1.83 trillion. (Credit: Rensselaer/Kim and Schubert)

Innovations in photonics and solid state lighting will lead to trillions of dollars in cost savings, along with a massive reduction in the amount of energy required to light homes and businesses around the globe, the researchers forecast.

A new generation of lighting devices based on light-emitting diodes (LEDs) will supplant the common light bulb in coming years, the paper suggests. In addition to the environmental and cost benefits of LEDs, the technology is expected to enable a wide range of advances in areas as diverse as healthcare, transportation systems, digital displays, and computer networking.

"What the transistor meant to the development of electronics, the LED means to the field of photonics. This core device has the potential to revolutionize how we use light," wrote co-authors E. Fred Schubert and Jong Kyu Kim.

Schubert is the Wellfleet Senior Constellation Professor of Future Chips at Rensselaer, and heads the university's National Science Foundation-funded Smart Lighting Center. Kim is a research assistant professor of electrical, computer, and systems engineering. The paper, titled "Transcending the replacement paradigm of solid-state lighting," will be published in the Dec. 22, 2008 issue of Optics Express.

Researchers are able to control every aspect of light generated by LEDs, allowing the light sources to be tweaked and optimized for nearly any situation, Schubert and Kim said. In general LEDs will require 20 times less power than today's conventional light bulbs, and five times less power than "green" compact fluorescent bulbs.

If all of the world's light bulbs were replaced with LEDs for a period of 10 years, Schubert and Kim estimate the following benefits would be realized:

Energy savings of 1.9 � 10²⁰�joules
Electrical energy consumption would be reduced by terawatt hours
Financial savings of $1.83 trillion
Carbon dioxide emissions would be reduced by 10.68 gigatons
Crude oil consumption would be reduced by 962 million barrels
The number of required global power plants would be reduced by 280

With all of the promise and potential of LEDs, Schubert and Kim said it is important not to pigeonhole or dismiss smart lighting technology as a mere replacement for conventional light bulbs. The paper is a call to arms for scientists and engineers, and stresses that advances in photonics will position solid state lighting as a catalyst for unexpected, currently unimaginable technological advances.

"Deployed on a large scale, LEDs have the potential to tremendously reduce pollution, save energy, save financial resources, and add new and unprecedented functionalities to photonic devices. These factors make photonics what could be termed a benevolent tsunami, an irresistible wave, a solution to many global challenges currently faced by humanity and will be facing even more in the years to come," the researchers wrote. "Transcending the replacement paradigm will open up a new chapter in photonics: Smart lighting sources that are controllable, tunable, intelligent, and communicative."

Possible smart lighting applications include rapid biological cell identification, interactive roadways, boosting plant growth, and better supporting human circadian rhythms to reduce an individual's dependency on sleep-inducing drugs or reduce the risk of certain types of cancer.

Pain Hurts More If Person Hurting You Means It

2008-12-21T13:51:18Z

In the study, participants who believed they were getting an electrical shock from another person on purpose, rather than accidentally, rated the very same shock as more painful. Participants seemed to get used to shocks that were delivered unintentionally, but those given on purpose had a fresh sting every time. (Credit: Image courtesy of Kurt Gray / Harvard University)

The research, published in the current issue of Psychological Science, was led by Kurt Gray, a graduate student in psychology, along with Daniel Wegner, professor of psychology.

It has long been known that our own mental states can alter the experience of pain, but these findings suggest that our perceptions of the mental states of others can also influence how we feel pain.

"This study shows that even if two harmful events are physically identical, the one delivered with the intention to hurt actually hurts more," says Gray. "Compare a slap from a friend as she tries to save us from a mosquito versus the same slap from a jilted lover. The first we shrug off instantly, while the second stings our cheek for the rest of the night."

The study's authors suggest that intended and unintended harm cause different amounts of pain because they differ in meaning.

"From decoding language to understanding gestures, the mind distills meaning from our social environment," says Gray. "An intended harm has a very different meaning than an accidental harm."

The study included 48 participants who were paired up with a partner who could administer to them either an audible tone or an electric shock. In the intentional condition, participants were shocked when their partner chose the shock option. In the unintentional condition, participants were shocked when their partner chose the tone option. Thus, in this condition, they only received a shock when their partner did not intend them to receive one. The computer display ensured that participants both knew their partner's choice and that a shock would be coming, to ensure the shock was not more surprising in the unintentional condition.

Despite identical shock voltage between conditions, those in the intentional condition rated the shocks as significantly more painful. Furthermore, those in the unintentional condition habituated to the pain, rating them as decreasingly painful, while those in the intentional condition continued to feel the full sting of pain.

Gray suggests that it may be evolutionarily adaptive for this difference in meaning to be represented as different amounts of pain.

"The more something hurts, the more likely we are to take notice and stop whatever is hurting us," he says. "If it's an accidental harm, chances are it's a one-time thing, and there's no need to do anything about it. If it's an intentional harm, however, it may be the first of many, so it's good to take notice and do something about it. It makes sense that our bodies and brains might amplify our experience of pain when we know that the pain could signal threats to our survival."

These findings speak to how people experience pain and negative life events. If negative events are seen as intended, they may hurt more. This helps to explain why torture is so excruciating � not only are torture techniques themselves exceptionally painful, but it's the thought that counts�and makes torture hurt more than mere pain.

On the other hand, if negative events are seen as unintended, they may hurt less. This may explain, in part, why people in abusive relationships sometimes continue to stay in them. By rationalizing that an abusive partner did not intend harm, some victims may reduce their experience of pain, which could make them less likely to leave the relationship and escape the abuse.

The research was supported by the National Institute of Mental Health, the Canadian Social Sciences and Humanities Research Council and the Institute for Humane Studies.

Life On Mars? Elusive Mineral Bolsters Chances, Researchers Say

2008-12-20T15:35:34Z

A Brown-led team found carbonate-bearing rocks in the sides of eroded mesas in the Nili Fossae region. Scientists believe the carbonates may have been formed at the surface when olivine-rich rocks were exposed, and altered, by running water. (Credit: NASA/JPL/JHUAPL/University of Arizona/Brown University)

What is less known is how much water occupied the red planet and what happened to it during its geological march to the present. Mostly, evidence has pointed to a period when clay-rich minerals were formed by water, followed by a drier time, when salt-rich, acidic water affected much of the planet. Assuming that happened, the thinking goes, it would have been difficult for life, if it did exist, to have survived and for scientists to find traces of it.

Now a research team led by Brown University has found evidence of carbonates, a long-sought mineral that shows Mars was home to a variety of watery environments � some benign, others harsh � and that the acidic bath the planet endured left at least some regional pockets unscathed.

If primitive life sprang up in pockets that avoided the acidic transformation, clues for it may remain.

"Primitive life would have liked it," said Bethany Ehlmann, a Brown graduate student and lead author of the paper that appears in the Dec. 19 edition of Science. "It's not too hot or too cold. It's not too acidic. It's a 'just right' place.'

Finding carbonates indicates that Mars had neutral to alkaline waters when the minerals formed in the mid-latitude region more than 3.6 billion years ago. Carbonates dissolve quickly in acid, therefore their survival challenges suggestions that an exclusively acidic environment later cloaked the planet.

The carbonates showed up in the most detail in two-dozen images beamed back by the Compact Reconnaissance Imaging Spectrometer for Mars, an instrument aboard the NASA Mars Reconnaissance Orbiter. Scientists found the mineral near a trough system called Nili Fossae, which is 667 kilometers (414 miles) long, at the edge of the Isidis impact basin. Carbonates were seen in a variety of terrains, including the sides of eroded mesas, sedimentary rocks within Jezero crater and rocks exposed on the sides of valleys in the crater's watershed. The researchers also found traces of carbonates in Terra Tyrrhena and in Libya Montes.

NASA's Phoenix Mars Lander recently found carbonates in soil samples, and researchers had previously found them in Martian meteorites that fell to Earth and in windblown Mars dust observed from orbit. However, the dust and soil could be mixtures from many areas, so the origins of carbonates have been unclear. The latest observations indicate carbonates may have formed over extended periods on early Mars and also point to specific locations where future rovers and landers could search for possible evidence of past life.

"This is opening up a range of environments on Mars," said John "Jack" Mustard, a Brown professor of geological sciences and a co-author on the Science paper. "This is highlighting an environment that to the best of our knowledge doesn't experience the same kind of unforgiving conditions that have been identified in other areas."

The researchers, including Brown graduate student Leah Roach and scientists from NASA, the Johns Hopkins University Applied Physics Laboratory, the Institut d'Astrophysique Spatiale at the University of Paris, the U.S. Geological Survey, Cornell University and the University of Nevada, have multiple hypotheses for how the carbonate-bearing rocks were formed and the origin of the water that shaped them. They may have been formed by slightly heated groundwater percolating through fractures in olivine-rich rocks. Or, they may have been formed at the surface when olivine-rich rocks were exposed and altered by running water. Yet another theory is the carbonates precipitated in small, shallow lakes. Either way, such environments would have boded well for primitive life forms to emerge.

"We know there's been water all over the place, but how frequently have the conditions been hospitable for life?" Mustard said. "We can say pretty confidently that when water was present in the places we looked at, it would have been a happy, pleasant environment for life."

NASA and the National Science Foundation funded the research.