To learn new motor skills, the brain must be plastic: able to rapidly change the strengths of connections between neurons, forming new patterns that accomplish a particular task. However, if the brain were too plastic, previously learned skills would be lost too easily. A new computational model developed by MIT neuroscientists explains how the brain maintains the balance between plasticity and stability, and how it can learn very similar tasks without interference between them. The key, the researchers say, is that neurons are constantly changing their connections with other neurons.
However, not all of the changes are functionally relevant — they simply allow the brain to explore many possible ways to execute a certain skill, such as a new tennis stroke. “Your brain is always trying to find the configurations that balance everything so you can do two tasks, or three tasks, or however many you’re learning,” says Robert Ajemian, a research scientist in MIT’s McGovern Institute for Brain Research and lead author of a paper describing the findings in the Proceeding of the National Academy of Sciences the week of Dec. 9. “There are many ways to solve a task, and you’re exploring all the different ways.”
As the brain explores different solutions, neurons can become specialized for specific tasks, according to this theory.
Drugs delivered by nanoparticles hold promise for targeted treatment of many diseases, including cancer. However, the particles have to be injected into patients, which has limited their usefulness so far. Now, researchers from MIT and Brigham and Women’s Hospital (BWH) have developed a new type of nanoparticle that can be delivered orally and absorbed through the digestive tract, allowing patients to simply take a pill instead of receiving injections. In a paper appearing in the Nov. 27 online edition of Science Translational Medicine, the researchers used the particles to demonstrate oral delivery of insulin in mice, but they say the particles could be used to carry any kind of drug that can be encapsulated in a nanoparticle.
The new nanoparticles are coated with antibodies that act as a key to unlock receptors found on the surfaces of cells that line the intestine, allowing the nanoparticles to break through the intestinal walls and enter the bloodstream. This type of drug delivery could be especially useful in developing new treatments for conditions such as high cholesterol or arthritis. Patients with those diseases would be much more likely to take pills regularly than to make frequent visits to a doctor’s office to receive nanoparticle injections, say the researchers.
Scientists achieved the first remote human-to-human brain interface this week, when Rajesh Rao sent a brain signal over the Internet that moved the hand of colleague Andrea Stocco—even though Stocco was sitting all the way across the University of Washington's campus. Using one human brain to direct another person's body via the Internet was an amazing breakthrough. But other feats of mind control are already realities, particularly in the realm of human machine interfaces. In some instances, human machine interfaces are becoming part of the human body. One new prosthetic even provides a sense of "touch" like that of a natural arm, because it interfaces with the wearer's neural system by splicing to residual nerves in the partial limb. The prosthetic sends sensory signals to the wearer's brain that produce a lifelike "feel," allowing users to operate it by touch rather than by sight alone.
This ability enables tasks many take for granted, like removing something from inside a grocery bag, and knowing how hard to grip items with the prosthetic hand. Researchers at Case Western Reserve University, now working with the Defense Advanced Research Projects Agency (DARPA), developed the prosthetic, which can be seen in action here and was unveiled in May 2013. DARPA is a leader in the development of advanced prosthetics, in part because more than 2,000 U.S. Service members have undergone amputations since 2000. Another DARPA-backed prosthetic arm flips this script by efficiently transmitting information from brain to arm, rather than vice versa, through a technique called targeted muscle re-innervation. The procedure rewires nerves from amputated limbs to enable more natural brain control of the prosthetic—and make possible some amazing abilities.
The advantages of learning of such skills are clear, but there is one ultimate perk. The creation of an independent learner, a learner who can adapt to changing contexts by engaging their network, a learner who can confidently navigate through the jungle of the Internet. But let’s not make students wait while teachers themselves come to terms with the power of the PLN. Students already have a very solid prior knowledge of the power and functionality of networks. They enthusiastically engage with them everyday for social and entertainment purposes. The skilled teacher is the one who can take that prior knowledge and enthusiasm and teach students to leverage it to their learning advantage.
Networking is not just a trend, a fad that will die out soon enough. The success of Facebook, Twitter and LinkedIn is not simply a result of cool fashionable technology. Dawson suggests networking is actually very intuitive, and his analogy of it as an organic breathing entity is useful. Indeed, all nature is organised in such a fashion, from DNA and cell functionality to chemistry to successful social interaction. Many things benefit from not being in isolation.
Defoe’s Robinson Crusoe was a warning, not just a story. Let’s not let students leave school in isolation, with only Friday on their minds. Let’s ensure they are well connected, independent, and empowered to learn anywhere, anytime.
It contains 99.9 percent of all the matter in our solar system and sheds hot plasma at nearly a million miles an hour. The temperature at its core is a staggering 27 million degrees Fahrenheit. It convulses, it blazes, it sings. You know it as the sun. Scientists know it as one of the most amazing physics laboratories in the universe. Now, with the help of new spacecraft and Earth-based telescopes, scientists are seeing the sun as they never have before and even recreating what happens at its very center in labs here on Earth. Their work will help us understand aspects of the sun that have puzzled scientists for decades. But more critically, it may help us predict and track solar storms that have the power to zap our power grid, shut down telecommunications, and ground global air travel for days, weeks, or even longer. Such storms have happened before—but never in the modern era of satellite communication. "Secrets of the Sun" reveals a bright new dawn in our understanding of our nearest star—one that might help keep our planet from going dark.
Viking sky wolves, Korean fire dogs, and African versions of celestial reconciliation - these are only some of the many ways people around the world, and through the ages, have sought to explain solar eclipses.
People in equatorial Africa will be treated to a rare view of a total solar eclipse this Sunday, November 3. Those living on the eastern North American coast, northern South America, southern Europe, or the Middle East, will get to see a partial solar eclipse. "If you do a worldwide survey of eclipse lore, the theme that constantly appears, with few exceptions, is it's always a disruption of the established order," said E. C. Krupp, director of the Griffith Observatory in Los Angeles, California. That's true of both solar and lunar eclipses. "People depend on the sun's movement," Krupp said. "[It's] regular, dependable, you can't tamper with it. And then, all of a sudden, Shakespearean tragedy arrives and time is out of joint. The sun and moon do something that they shouldn't be doing." What that disruption means depends on the culture, and not everyone views an eclipse as a bad thing, said Jarita Holbrook, a cultural astronomer at the University of the Western Cape in Bellville, South Africa. Some see it as a time of terror, while others look at a solar eclipse as part of the natural order that deserves respect, or as a time of reflection and reconciliation.
Oil, gas, and chemical dispersants contaminated thousands of square miles of marine and coastal habitat. Many animals were killed or sickened outright, but on the one-year anniversary of the Gulf oil spill, scientists still don't know the extent of the spill's effects on most species. Bottlenose dolphins have been dying in unusually high numbers in northern Gulf waters since February 2010, two months before the oil spill began, and the trend continues today. Since January, 68 premature, stillborn, or newborn calves have washed ashore.
The Gulf oil spill is certainly on the list of suspects in the recent dolphin deaths, but it's too early to say for sure, Blair Mase, coordinator of the Southeast Marine Mammal Stranding Network of the National Atmospheric and Oceanic Administration, told National Geographic News in March. Only a handful of obviously oiled dolphins have been recovered. But a recent study from the University of British Columbia estimated that the actual number of dolphins and whales killed by the spill could be 50 times higher than official tallies suggest, putting the death toll in the thousands.