The Brainy Science of Finding Your Car Keys

The saying that it's impossible to step into the same river twice may be true, at least as far as the brain is concerned.

Different neurons in a brain region called the dentate gyrus fire when encountering a place for the first or second time. Different brain cells also fire to distinguish subtle changes in familiar terrain, new research in mice suggests.

The findings, which were published March 20 in the journal eLife, may help unravel how the brain tracks minute changes in our everyday environments, a process known as pattern separation. The phenomenon is how we find our car keys or wallet, for instance.

"Everyday, we have to remember subtle differences between how things are today, versus how they were yesterday, from where we parked our car to where we left our cellphone," said study co-author Fred H. Gage, a neuroscientist at the Salk Institute, in a statement. "We found how the brain makes these distinctions, by storing separate 'recordings' of each environment in the dentate gyrus." [10 Odd Facts About the Brain]

Small differences

Several studies suggested that a brain region called the hippocampus helps people navigate and orient themselves in space, in part by retrieving memories from different environments. For instance, London cabbies have more hippocampal grey matter after training in navigation.  

But exactly how the hippocampus sifted memories of new and familiar places wasn't fully understood.

Previous studies found that a sub-region of the hippocampus, called the dentate gyrus, helped the brain pick out important patterns from detail-rich memories of the environment — such as where someone placed their keys from one day to the next. The same region may play a role in the eerie feeling of déjà vu.

Different brain cells

To find out, Gage and his colleagues measured firing from neurons, or brain cells, in mice as they navigated a new chamber.

They then recorded their brain activity while the same mice explored either the exact same chamber or a very similar one.

The team found that neurons in a sub-region of the hippocampus called CA-1 fired when mice were in both new and familiar environments. But in the dentate gyrus, different groups of neurons fired in undiscovered territory versus familiar spaces. Different collections of cells also fired in the dentate gyrus in the two similar chambers.

The findings suggest the neurons that encode our memories of a new place are different from those that fire when we revisit it and notice its subtle transformations. 

Follow Tia Ghose on Twitter @tiaghose. Follow LiveScience @livescience, Facebook & Google+. Original article on LiveScience.com.

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Finding Another Earth: How Will Scientists Confirm It Exists?

LONG BEACH, Calif. — The announcement this week that astronomers have found a potential alien world that could be the most Earth-like exoplanet yet is raising a big question: How will scientists confirm the existence of a true alien Earth?

While NASA's planet-hunting Kepler space telescope, which discovered the newfound Earth-like planet candidate KOI 172.2, is great for finding large numbers of exoplanets, it is not our best bet for characterizing an Earth twin circling a distant star, researchers say.

In order to understand what an "alien Earth" candidate really looks like, it takes a more refined approach than what Kepler can provide at the moment.

"It’s a statistical mission," Kepler deputy science team lead Natalie Batalha said at the 221st meeting of the American Astronomical Society on Tuesday (Jan. 8).

The Kepler mission is designed to find out how many possible exoplanets there could be in any given part of the galaxy. The space telescope launched in 2009 and stares unblinking at a single patch of the sky to scan for dips in light from stars, a telltale sign of an orbiting planet passing in front of the star. Kepler's observations can tell scientists where a planet is in relation to its home star, but the spacecraft has little to add about important details such as an exoplanet's climate, researchers said. [Most Earth-like Exoplanet Discovery Explained (Infographic)]

But how can scientists study those important questions that need to be answered before a planet can be deemed a true Earth twin?

Finding Earth’s twin

The Kepler mission is a starting point in the search for a true Earth-like planet, Nicolas Cowen a postdoctoral fellow in astronomy at Northwestern University in Evanston, Ill. told SPACE.com. "Kepler just told us how big the telescope we have to build is."

There could be more than 17 billion Earth-sized planets in the Milky Way galaxy alone, but that doesn’t mean they’re easy to research once detected. Once planets of interest are confirmed by Kepler, then other instruments can be used to investigate the specifics of the planet.

A ground-based telescope could be just the right tool for finding Earth’s twins, said Cowen. If the exoplanet in question is near enough to the Earth and in exactly the right position, researchers could aim a 10-meter (33 foot) dish toward the planet to optically observe its transit between the Earth and its home star. After researchers have measured the radius of the planet, and if a telescope can make direct observations of the planet in question, Cowen said, then it is just a matter of patience.

Cowen added that all it takes after a researcher knows the size and rotation of the planet is as much observation time as possible. Watching the way a planet rotates and taking measurements of the different colors that come in and out of view as the planet orbits its star gives researchers a sense of what might lie under the surface of the atmosphere.

Water, land and clouds reflect light in different ways, and by directly observing those reflections, astronomers like Cowen can start to see how an exoplanet might be an Earth twin.

“That’s what would happen in an ideal world,” Cowen said.

Closer than we think?

Those days of "ideal" research might not be as far off as some believe. Cowen thinks that it could only be a matter of time before astronomers are able to peer into the atmosphere of an exoplanet and see what’s happening on the surface using a ground-based telescope.

In a presentation earlier this week, astronomer Ian Crossfield suggested that it’s likely that an Earth-size planet in the “habitable zone” of an M-dwarf star — a type of star smaller and dimmer than the sun, but plentiful in the Milky Way — will be found within 31 parsecs of Earth, a relatively short distance in astronomical terms.

“This is the first meeting where any of these ideas have even brought up,” Cowen said. “It’s very exciting.”

You can follow SPACE.com staff writer Miriam Kramer on Twitter @mirikramer. Follow SPACE.com on Twitter @Spacedotcom. We're also on Facebook & Google+. 

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The Science of Finding the Perfect Christmas Gift

For all of recorded history, people have been giving presents for a myriad of reasons: to show affection, curry favor, or fulfill familial duty. And the custom goes beyond the human species. Even family cats are known to bequeath presents of dead mice or birds on their owners.

"It's an act of social communication," said SunWolf, a communications professor at Santa Clara University. "Without using words, you're always saying something: 'I wish we could be closer, I think of you, I miss you.'"

But figuring out how to translate your love for someone else into that perfect gift can be stressful. Here are some tips for making gift-giving a joy for both the giver and the receiver.

Get one big present

A big present looks more impressive when it stands on its own, according to a study reported last year in the Journal of Consumer Research. Putting a tube of lip balm in with the cashmere sweater will make gift-givers view the present less favorably.

That's because people tend to average out the value of the present, making the whole package seem cheaper.

Use that wish list

Buying something straight off a person's wish list may seem lazy, but it may be the safest strategy, said Nicholas Epley, a psychologist at the Booth School of Business at the University of Chicago.

Epley's team has found that when people receive a gift they like, they didn't actually care whether someone put a lot of careful thought into selecting it.

His team conducted a study at the Museum of Science in Chicago where people were asked to either randomly select or carefully choose a high-rated or low-rated present from the gift shop for another person. Those who got coveted items didn't think much about the giver's intentions. [Geeky Gifts: Holiday Guide for Science-Lovers]

"What we found is that a gift giver's thoughtfulness, or how thoughtful you thought the gift giver was, counted only when you got a crappy gift," Epley told LiveScience.

Put some thought into it

But despite the fact that a good gift needs no context, getting a thoughtful gift does have benefits — for the giver.

Givers who were asked to think carefully about a gift choice felt closer to the receivers than those who were asked to pick randomly, Epley said. That held even when givers were offering presents to random strangers.

"Perspective taking, or imagining being in another person's shoes, makes you feel closer to the person," he said.

But mention the thought

Thoughts do wind up counting when you get a bad gift, Epley found. For instance, when the museum visitors in his study received a low-rated ruler that said "Rulers of Science" on it, they were more likely to appreciate the gift if they were told how the giver had thoughtfully selected it.

So it might be good to write a little note on that card to Uncle Marv describing why that life-size replica of George Washington made you think of him.

"The practical message of this is not that you shouldn't put thought into a gift. You shouldn't assume your thoughts will count like you think they do or that people will magically know how thoughtful you are," Epley said.

Agree to opt out

It's also okay to stop giving gifts, even if you have done so in the past. That friend you met in 1989, the grandmother who knits progressively uglier sweaters, or the co-worker who you don't know very well — if thinking about giving or receiving is stressful, it's okay to not give a gift as long you communicate it clearly, SunWolf told LiveScience.

"Just like any relationships that don't work anymore we need to have an exit strategy," she said. Instead, come up with an alternate way of showing you care, like telling grandma "The gift giving thing isn't necessary anymore grandma, I'd be happy with just having lunch with you."

Consider regifting

There's also regifting — recycling a gift you've received previously — which new research in the journal Psychological Science suggests may not be as offensive as once thought, at least to the gift giver. To improve acceptance of regifting, the researchers suggested voicing your feelings when recycling a present, even expressing to the receiver that it's OK for them to do what they like with the gift (even if that means passing it along next year).

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New Study Throws Dark Matter Finding Into Question (SPACE.com)

A new study of dark matter, the mysterious hidden stuff thought to pervade the universe, casts doubt on a previous finding that offered hope that dark matter had finally been seen.

In 2008, a European-Russian satellite called Payload for Antimatter Matter Exploration and Light nuclei Astrophysics (PAMELA) discovered a strange overabundance of particles called positrons, which are the antimatter counterpart to electrons. Matter and antimatter, which have the same mass but opposite charges, destroy one another when they meet.

According to theory, when a particle of dark matter collides with its antiparticle, they annihilate, unleashing a burst of energy and exotic particles. Dark matter is thought to make up 98 percent of all matter in the universe and 23 percent of its total mass and energy. Scientists have yet to directly detect invisible dark matter, but its existence is inferred based its gravitational pull on regular matter.

The positrons found by PAMELA were thought to be the products of dark matter annihilation with antimatter, and scientists were hopeful that the tantalizing discovery could prove the existence of the elusive dark matter.

But a new study has raised more questions about PAMELA's discovery. Researchers at the Kavli Institute for Particle Astrophysics and Cosmology (KIPAC) at Stanford University in California confirmed the overabundance of positrons, but when they did not see a sudden drop-off of this excess beyond a certain energy level, they knew something was wrong.

"If the antimatter we measure is coming from the annihilation of dark matter particles, then the positron excess should drop off fairly suddenly at an energy level that corresponds with the mass of the dark matter particle," study co-author Stefan Funk, an assistant professor of physics at Stanford University, said in a statement.

Rather, Funk and his colleague, Justin Vandenbroucke, found that the number of positrons continued to increase in line with the level of energy. [7 Surprising Things About the Universe]

"Some have concluded that this altogether rules out dark matter as a source of the antimatter we're measuring," Funk said. "At the very least this means that if the positrons are coming from dark matter annihilation, then dark matter particles must have a higher mass than allowed by the PAMELA measurement."

But the results are not necessarily a definitive strike against the finding, the researchers said.

"We're taking an observational point of view and simply reporting the data that we observe," Vandenbroucke said. "However, I know that articles are already appearing that say our result likely rules out the dark matter interpretation. Personally, I think that is too strong of an interpretation."

Additional observations will be needed to settle the debate, the researchers said. One instrument in particular, the antimatter-hunting Alpha Magnetic Spectrometer (AMS), is expected to yield helpful results.

NASA's space shuttle Endeavour carried the AMS experiment to the International Space Station in May, where it was installed on the exterior of the complex. It has been operating ever since. This detector should be able to collect more precise data at higher energies, Vandenbroucke said.

"AMS has a very large magnet in its detector and so can naturally and very easily distinguish between electrons and positrons," Funk said. "That experiment will most likely be able to make a final statement on this. It's something we are all eagerly awaiting."

Funk and Vandenbroucke used NASA's Fermi Gamma-ray Space Telescope, which studies the highest energy forms of light. Since the telescope is designed to detect neutral light particles, called photons, it does not have a magnet to separate negatively charged electrons and positively charged positrons.

The researchers were forced to improvise, but luckily a natural magnet exists close to home: Earth. The planet's magnetic field naturally bends the paths of charged particles that almost continuously rain from space, they explained.

The scientists then studied geophysical maps of Earth and calculated how the planet filters out charged particles seen by the telescope, in a novel approach at the intersection of astrophysics and geophysics.

"The big takeaway here is how valuable it is to measure and understand the world around us in as many ways as possible," Vandenbroucke said. "Once you have this basic scientific knowledge, it's often surprising how that knowledge can be useful."

The researchers detailed their results in a paper submitted to the journal Physical Review Letters.

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Month-end target mooted for finding "no Higgs"

A scientist holds a glass of champagne after the first successful collisions at full power at the Compact Muon Solenoid (CMS) experience control room at the Large European Organisation for Nuclear Research (CERN) in Meyrin, near Geneva, March 30, 2010.

Credit: Reuters/Denis Balibouse

By Robert Evans

GENEVA | Tue Sep 6, 2011 10:17am EDT

GENEVA (Reuters) - U.S.-based physicists said on Monday they hope to have enough data by the end of this month to establish if the elusive Higgs boson, a particle thought to have made the universe possible, exists in its long-predicted form.

If the answer is no, scientists around the globe will have to rethink the 40-year-old Standard Model of particle physics which describes how they believe the cosmos works.

The physicists, at the Fermilab research center near Chicago which operates the Tevatron collider, have been in friendly competition with colleagues at CERN near Geneva whose giant LHC machine is also seeking the Higgs.

In an e-mail to Reuters in Geneva, Fermilab communications director Katie Yurkewicz said Tevatron was on track to have by September 30 the information "to rule out the existence of a Higgs boson with a mass within the most likely range."

Both Tevatron, operating for the past 28 years, and CERN's Large Hadron Collider, started up on March 30 2010, have been trying to find the boson -- postulated as the particle that gave mass to matter after the Big Bang 13.7 billion years ago -- within that range.

If it is not there, scientists say, then the multi-national research teams at both centres will have to start looking in the data gathered and more to come for something else -- a different sort of Higgs or some other particle.

But if it is somewhere there, Yurkewicz and her Fermilab colleague Robert Roser say, the Tevatron would not have enough data to confirm its existence before September 30 -- when the U.S. collider, denied necessary funds, closes down for good.

MULTIPLE SIGHTINGS NEEDED

Scientists at both centres say there will have to be multiple sightings of the Higgs -- each of which will have to be minutely scrutinized to ensure they are what they appear to be -- before a discovery can be announced.

Reaching the conclusion that it is not where it should be is much easier.

In the two machines -- the LHC oval-shaped and the Tevatron circular but smaller -- particles are smashed together at near the speed of light, recreating the primal chaos of flying matter a tiny fraction of a second after the Big Bang.

The result of those collisions -- and there have been trillions of them -- are recorded on computer disc and studied by scientists around the world for any trace of the Higgs, a key element of the Standard Model, and of any new phenomena.

Scientists at CERN, formally the European Organization for Nuclear Research, have themselves been gathering data from collisions at an ever-growing rate but have yet to spot more than a fleeting hint that it might exist.

"The Higgs boson has been rather elusive so far and no-one really knows what it will look like," wrote CERN scientist Paulime Gagnon in her blog on Monday.

"But if it exists, and if it is the one predicted by the Standard Model, then we know how to set traps to catch some."

CERN's director-general Rolf Heuer has said he expects proof one way or another to emerge in 2012, at the end of which the $10 billion LHC will shut down for a year to be prepared for collisions at twice the present force.

But some CERN researchers have suggested that the vast amount of data they are collecting could allow them to come to at least a preliminary conclusion -- Higgs or no Higgs -- by the end of this year.

(Reported by Robert Evans; Editing by Andrew Heavens)

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