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Jewish World Review Feb. 21, 2001 / 28 Shevat, 5761
Jenni Laidman
http://www.jewishworldreview.com -- Get ready to reorganize your brain. Learning a second language, recovering from a disabling stroke, or even improving reading skills in young adults, are all within reach, scientist say, as they uncover how the human brain allows people to learn late into life. The scientists spoke Saturday at the annual meeting of the American Association for the Advancement of Science. "There's a revolution occurring in our understanding of the contributions of brain plasticity," said Mike Merzenich, a researcher at the University of California-San Francisco. While it previously was thought that there was only a small window for many kinds of learning that closed during childhood, "That view is incorrect," Merzenich said. "The machinery of the brain, especially the cortex, is continually remodeling itself." Merzenich conducted some of the earliest research on the brain's ability to reorganize continuously, a quality called plasticity. He continues to work with children and young adults to improve reading skills. Dr. Edward Taub of the University of Alabama-Birmingham has demonstrated this brain plasticity in his work with stroke victims. When a patient loses use of a limb in a stroke, Taub's Constraint-Induced Movement Therapy can teach him to use the limb again. The therapy involves intensive, repetitive movement of the impaired limb and restraint of the unaffected limb. Taub's methods have been successful even if the patient didn't begin therapy until a year after the stroke. He began his research in monkeys. Animals deprived of sensation in an arm through surgery soon give up trying to move it anymore. "The monkey stops using it because he learns not to. In the first few weeks after surgery, he can't use the limb." But when the monkey was prevented from using the healthy arm, it regained use of the limb impaired in surgery. In stroke patients, Taub restrains use of the limb unaffected by stroke and has the patient move the affected limb six hours a day for two weeks to restore limb function. Brain imaging studies show that the portion of the cerebral cortex devoted to the limb shrunk by half after a stroke. But the cortex section doubled as a result of the intensive therapy. Patients are being enrolled in a nationwide clinical trial of this therapy. The approach has been used successfully in some spinal cord injuries and in cerebral palsy "where we get better results than we ever get in an adult population," Taub said. The fact that children do better than adults in a variety of learning tasks reflects the price we pay for a life of learning. The brain often uses new information to reinforce things it knows. That creates a problem for adults when they try to learn a second language. Dr. James McClelland of Carnegie Mellon University focuses on adult acquisition of a second language. "The brain is still capable of learning in adulthood, but the habits of mind take it in the wrong direction," he said. "The more you've entrenched a set of skills, the more resistance you will have to further change," McClelland said.
"You even hear the new language the way you hear your native
language," McClelland
Jenni Laidman is a writer with the Toledo Blade. Comment by clicking here.
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