Meditation is associated with stronger connections between brain regions. Photo courtesy of R_x - renee barron.

Meditation is the practice of focusing your mind on a single thought or idea for an extended period of time in order to achieve some benefit. The goals of meditation can vary and include increased focus, increased awareness or “presence,” better memory, decreased stress and achieving a state of enlightenment. Physiological advantages have also been reported, such as decreased blood pressure and pain reduction.

Though meditation has been practiced all over the world for thousands of years, the mechanism by which it works is still largely unknown. A recent study published in the journal NeuroImage suggests that mediation may work by strengthening the connections between brain regions, thereby building more robust neural networks.

The study compared age and gender matched meditators with non-meditators. Researchers used a method called diffusion tensor imaging (DTI) that detects the size and direction of white matter tracts in the brain. White matter is made up of long neuronal processes called axons that transmit information from one area of the brain to another. DTI is used to measure the integrity of white matter tracts and is thought to indicate the strength of neural connections.

Meditators had stronger DTI measures than non-meditators, particularly in the corticospinal tract (axons from the brain to the rest of the body), the superior longitudinal fasciculus (connections between executive brain areas and sensory regions) and the uncinate fasciculus (connects executive brain areas to emotion and memory regions). Meditators also seemed to have less age-related degeneration.

Though this was not a randomized controlled trial and cannot determine if mediation was the cause of the structural changes, this study opens a new area of research for exploring the role of meditation and brain training in strengthening and preserving the neural connections necessary for memory and other important cognitive tasks.

Caption: A new design for comuter memory would send information shooting along wires like cars along a racetrack. Image source: Jina Lee, Wikimedia Commons.

The word racetrack has quite a history in American culture. It conjures up images of horse racing, with beautiful animals, colorful spectators, cheap hot dogs, and expensive gambling. Perhaps more prominently, it brings automobiles to mind. The Ford Model-T made cars affordable, and Prohibition catalyzed the development of brawny speedsters that could outmuscle the police cruisers, but it was the automobile’s marriage to the racetrack that finally transformed stock car racing into the booming phenomenon that it is today. Now a team of researchers at IBM lead by Stuart Parkin would like us to start associating the word with computer memory.

Racetrack Memory, as the research team has coined it, is a new idea that could compete with some of the most popular memory devices in use today. In an article published in the December 24th issue of the journal Science, Parkin and collaborators have measured some key features of magnetism that bring the idea one step closer to viability.

Devices today almost all store their memory using either FLASH or magnetic hard drives. Both technologies have undergone dizzying improvements recently in storage capacity, cost, and reading and writing speed. Still, they have a few inherent drawbacks. Traditional magnetic hard drives are inexpensive and have an enormous storage capacity. However, they require moving parts, which costs a device energy and consequently battery life. FLASH memory has no moving parts, but it takes a relatively long time to write information, and FLASH continues to be more expensive than magnetic hard drives.

Racetrack Memory is proposed to be a third alternative. Information would be stored magnetically in a similar manner to a magnetic hard drive. However, instead of storing the information in stationary bits on a disk, it would be stored in thin nanowires, and if the proper signals are applied, the information could be zipped through the wires from one place to another — like a car shooting down a racetrack — with no need for moving parts. IBM has big ambitions for the new memory architecture, claiming that it would enable a single portable device to hold more than 2,000 movies while running on a battery that would last for weeks.

Particularly exciting is the fact that the basics of Racetrack Memory are becoming rapidly understood. “In the past ~5 years we have demonstrated that the physics underlying the Racetrack Memory that I proposed in 2004 or so works!” Dr. Parkin said. “Thus, there are no fundamental roadblocks to making Racetrack Memory a reality.” This is a contrast with some of the more exotic ideas out there for computer memory (see my last blog post on multiferroics, for example).

So why can’t I seem to find a media player that doesn’t conk out after half a day’s use yet? Parkin said that while the physics of Racetrack Memory architecture works, many engineering hurdles still need to be overcome. He was unwilling to put a definite time estimate on when devices might begin to show up in the marketplace. “Of course,” he joked, “if you write a large check, we can build you a prototype Racetrack Memory in just two to three years (depending on the size of the check!).”

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A hard drive surface as viewed using an electron microscope. Memory is stored magnetically in the pattern of dark and light patches.Image from Wikimedia Commons. / CC Attribution-Share Alike 3.0 Unported

The Spanish filmmaker Luis Buñuel once wrote, “You have to begin to lose your memory, if only in bits and pieces, to realize that memory is what makes our lives. Life without memory is no life at all.” The same might be said (albeit with less existential fanfare) of memory in the world of computers.

In the form of bigger hard drives, computer memory has revolutionized our ability to store everything from research articles, to Hollywood films, to cookbooks. Historically these devices have been enabled through the clever manipulation of magnetism. However, recent advances at UC Berkeley and elsewhere in the development of exciting materials known as multiferroics may be changing that recipe for success.

The inside of a modern hard drive works by almost exactly the same principles that kitchen magnets exploit when holding a wedding invitation to your fridge. A material with such magnetic (or more technically, ferromagnetic) properties such as a kitchen magnet is extremely useful because of its directionality. If you place two magnets together head-to-tail they attract, whereas if you flip the top magnet and repeat the process they push each other apart. A computer essentially writes and reads information by flipping little magnetic patches up or down and measuring what happens to another magnet placed on top of them.

There is a major difference, however, between the individual size of a magnet on your hard drive and a kitchen magnet. Each computerized bit on a hard drive may be 10 billion times smaller than the size of your thumbnail in area (see the figure above). It is precisely the smallness of these details that enable a computer to remember so much information.

In recent years, however, scientists have been playing around with more exotic forms of data storage. It turns out that some very specialized materials are not only like to be magnetically ordered, but are also naturally charged. That is to say, one side of the material likes to accumulate more electrons than the other side. Charging is a common enough effect in nature. When you rub a balloon against your hair you pull electrons from your hair onto the balloon. The subsequent tingling effect is a direct result of this charging. Thunderclouds exhibit charging when they accumulate massive amounts of electrons at their bases. When the energy is finally released it can result in spectacular shows of lightning.

When charging occurs naturally in a material, scientists say that the material is ferroelectric. A material that is both ferroelectric and ferromagnetic (or in cases, a variation called antiferromagnetic) is said to be multiferroic. If properly exploited, these extra properties may be quite useful in technology.

An experiment published last Sunday in the Nature Materials by researchers at UC Berkeley showed that electric voltages applied to the multiferroic bismuth ferrite could be used to directly manipulate a nearby material’s magnetic properties.

Stephen Wu, the paper’s lead author, explained that this could be an incredible step forward for technology. While people have been able to control magnetism using electricity before, never have they been able to do it in a way that requires no power, and never before have they been able to switch the direction of this magnetism so quickly. Such a development both saves energy and battery life, but also reduces the amount of heat within a system, thereby making it scalable. “You can make a lot of it, it’s static, and you can do it really fast,” said Wu, elaborating that if you could get such a system to work at room temperature, this magic combination of features could revolutionize the computing industry. In some of the most imaginative visions of the future, computers may not even be based on semiconductors or silicon at all, but rather on these new multiferroics and related compounds.

Silicon Valley may need to consider a name change.

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This is the second of two stories born out of an afternoon at UCSF's Memory and Aging Center, where a team of scientists, led by Dr. Bruce Miller, is trying to tease out the differences between as many as 200 dementias that affect aging brains.

The two stories have a lot in common: Both introduce us to people who have lived with extremely difficult degenerative diseases: ALS in "Decoding the Emotional Brain," and frontotemporal dementia in this week's story. Both open up provocative questions about human nature. And neither would have happened without the generosity of a Northern California family – in this case, Cassandra Shafer, who drove down from Forestville with her daughter, Columbia, to tell me about Cassandra's husband and Columbia's father, Keith Jordan.

In these video clips, you meet Keith Jordan in the second half of his disease, after doctors at UC Davis and UCSF diagnosed him with frontotemporal dementia. The videos were taken at UCSF over the course of many hours doctors spent studying Keith and his symptoms. In them, we glimpse of two of Keith's FTD-caused obsessions: joke telling and music. (We also see one of the first symptoms to have emerged: his Jerry Garcia hairdo.)

At first glance, Keith's behavior might strike you as more eccentric than brain-damaged, which is precisely why FTD can take so long to diagnose. If you're a doctor with a 15-minute appointment slot, frontotemporal dementia might just look like a midlife crisis. What we don't see in the video clips are the five heartbreaking years that Cassandra spent trying to figure out what was happening to her husband – a search that included marriage and career counseling, the full gamut of conventional western specialists, yoga, meditation, chelation therapy, replacing every household cleaning product, every pot and pan, all the way to shamanic soul retrieval and exorcism – all while his behavior grew more erratic and difficult to be around. It's impossible to overstate the drain – both emotional and financial — that this search brought on Keith's family.

Keith died in May and Cassandra is still, she says, "inching her way" out of the "foreign land" that FTD plunged her into. As unlikely as it sounds, I think she takes some comfort in the fact that Keith's illness also gave doctors a chance to explore profound questions about human nature and the extent to which the structure of our brains determines who we are.

FTD can turn Democrats into Republicans, and vice versa. People with no interest in art begin to paint obsessively. As the neurons in Keith's right frontotemporal lobe (just behind the right eyebrow) died, his taste in music, his sense of humor, his relationships with his family members and friends changed completely. Our self, in other words, may owe much more to the way our brains are built than we'd care to acknowledge.

And what to make of the fact that this same part of the brain that shapes personality is also responsible for reading other people's reactions? People with some forms of FTD can't empathize with others (hear more about this in our slide show about FTD and art) or read the emotion on another person's face. Not only do they experience radical personality changes, but they lose the ability to sense others' reactions to them. In other words, how we define ourselves – whether we consider ourselves funny, smart, ambitious — seems to have everything to do with how others define us. We are all, in other words, people people.

Which begs the question: What about people raised in isolation, without the critical feedback loop of social interaction? What does FTD tell us, for example, about children who have been deeply neglected in orphanages? Or – taking another angle entirely — autistic people, who have trouble empathizing with others? What does self-perception look like in those who can’t perceive those around them?

If all this is giving you a headache, you might spend some time exploring the web extras we've produced for these two stories. Here, Bruce Miller explains why frontotemporal dementia can bring with it an artistic renaissance. And here, we introduce you to Matt Cheney and find out what his compulsive laughing and crying jags might reveal about emotion and the human brain.

Then use our blog, below, to let us know what you think.

Listen to the Beyond Alzheimer's radio report online, and watch our Web Extra: Dementia and Artistic Renaissance slideshow.

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