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Archive - Sep 23, 2009

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Retinal Implant May Restore Some Vision

Researchers at MIT, together with collaborators, have developed a prototype retinal implant for people who have lost their vision from retinitis pigmentosa or age-related macular degeneration, two of the leading causes of blindness. The implant would help restore some vision by electrically stimulating the nerve cells that normally carry visual input from the retina to the brain. Patients who receive the implant would wear a pair of glasses with a camera that sends images to a microchip attached to the eyeball. The glasses also contain a coil that wirelessly transmits power to receiving coils surrounding the eyeball. When the microchip receives visual information, it activates electrodes that stimulate nerve cells in the areas of the retina corresponding to the features of the visual scene. The electrodes directly activate optical nerves that carry signals to the brain, bypassing the damaged layers of retina. The chip would not restore normal vision, but could help blind people more easily navigate a room or walk down a sidewalk. "Anything that could help them see a little better and let them identify objects and move around a room would be an enormous help," said Dr. Shawn Kelly, a member of the research team. The researchers hope to start testing the prototype in blind patients within the next three years, after some safety refinements are made. The work was published in the October issue of the IEEE Transactions on Biomedical Engineering. [Press release]

Whale Skeletons Home to Nine New Species

A recent Ph.D. thesis from the University of Gothenburg in Sweden, reports the identification of nine new species of bristleworm, a type of worm typically found on whale skeletons. Some previously identified species of bristleworm are so specialized in eating dead whales that they would have problems surviving elsewhere. One species uses its root system to penetrate the whale bones when searching for food. Other species specialize in eating the thick layers of bacteria that quickly form around the bones. When a whale dies, it sinks to the seafloor and becomes food for an entire ecosystem. Dead whales constitute an unpredictable food source; it is impossible to know when and where a whale is going to die, and when it does, the food source does not last forever. Nevertheless, some marine species have specialized in feeding on whale cadavers. A dead whale is an enormous source of nutrients. In fact, one cadaver offers the same amount of nutrients that normally sinks from the surface to the seafloor in 2,000 years, and this is of great benefit to innumerable species: First, the meat is eaten by, for example, sharks and hagfish, then tremendous numbers of various organisms come to feast on the skeleton. Four of the new bristleworm species were found on whale cadavers placed at a depth of 125 meters in the new national park Kosterhavet off the coast of Strömstad, Sweden. The other five species feed on whale bones in the deep waters off the coast of California. The family tree of bristleworms was explored using molecular data. The DNA analyses showed that there are several so-called “cryptic” bristleworm species, meaning species that, despite appearing identical, differ very much genetically.