While that headline may overstate the case slightly for comic effect, researchers say the gist of it is true: Stroke patients with impaired vision who listened to their favorite music showed vastly improved visual processing. Says lead researcher David Soto: “One of the patients chose Kenny Rogers, another Frank Sinatra and the third a country rock band. It’s not a particular kind of music that’s important, as long as the patient enjoys it” [Daily Mail].
Participants in Soto’s study had suffered lesions to their brains’ parietal cortex, a region central to visual and spatial processing. This left them with a condition called visual neglect, in which people lose half their spatial awareness. Victims will sometimes eat food from only one side of their plate, shave one side of their faces, or — as tested in the study — fail to perceive visual prompts on one side of a computer screen [Wired].
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Researchers have developed a treatment based on an injection of neural stem cells encased in a biodegradable polymer that replaced the brain tissue in rats that had been damaged by stroke. Led by British neurobiologist Mike Modo, the team was able to show that the hole in the brains of rats caused by a stroke was completely filled with “primitive” new nerve tissue within seven days. This raises the possibility of radically better treatments for a condition that is the leading cause of adult disability in industrialized countries [Technology Review].
Previous stem cell research in rats with stroke damage had seen some success, but was limited by the tendency of the cells, which lack structural support, to migrate into tissue outside the targeted area. For the new study, which will be published in Biomaterials, the researchers used the polymer PLGA to construct tiny balls one-tenth of a millimeter thick, and loaded them with neural stem cells. These were injected into holes in the brain created when the immune system removes dead tissue caused by a stroke. The polymer’s ready-made support structure helped the stem cells to form new brain tissue in the cavity [BBC].
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In a remarkable experiment, researchers found that a man who was rendered completely blind by several strokes could deftly navigate an obstacle course unaided, easily avoiding boxes and sidling around pieces of office equipment. The patient, known only as TN, was left blind after damage to the visual (striate) cortex in both hemispheres of the brain following consecutive strokes. His eyes are normal but his brain cannot process the information they send in, rendering him totally blind [BBC News]. Researchers say TN’s successful performance was an example of the phenomenon “blindsight,” and say it suggests that some small amount of information is being transmitted from his undamaged eyes to a more primitive part of his brain, which operates beneath the level of consciousness.
TN usually walks with a cane, but researcher Beatrice de Gelder convinced him to put it aside and to try to navigate the obstacle course without its help. He was able to do so flawlessly, despite being unable to consciously see any of the obstacles. Head down and hands loose by his side, he twisted his body to slalom slowly but surely between a camera tripod and a swingbin, and neatly stepped around a random series of smaller items. “At first he was nervous,” says de Gelder. “He said he wouldn’t be able to do it because he was blind.” The scientists broke into spontaneous cheers when he succeeded [Nature News].
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Researchers have made a map of the human brain that shows a dense network of connections at the top of the cerebral cortex, suggesting that electrical signals travel through this hub on their way to more specialized regions. “This is just about the coolest paper I’ve seen in a long time, and forward-looking in terms of where the science is going,” said Dr. Marcus E. Raichle, a professor of neurology and radiology… who was not involved in the research. He added, “They’ve found in the brain what looks like a hub map of the airline system for the United States” [The New York Times].
An international team of researchers used a technique called diffusion spectrum imaging to map the connections between different parts of the brain. The technique traces the path of water moving along axons, long fibers that extend from a neuron’s main body and carry electrical signals [Science News]. They found the most connections at the top of the cortex along the crack that separates the brain’s two hemispheres. According to researchers, that area is not only a relay station, it’s also the area that’s most active when the brain is in “default mode,” the activation state present when the brain is not engaged in any specific cognitive task [The Scientist].
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