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---------------------------------------------------------------------------- The way we learn -- and keep from forgetting ---------------------------------------------------------------------------- Copyright 1997 Nando.net Copyright 1997 The Associated Press WASHINGTON (August 7, 1997 6:58 p.m. EDT) -- After learning a new physical skill, such as riding a bike, it takes six hours to permanently store the memory in the brain. But interrupt the storage process by learning another new skill and that first lesson may be erased, according to research into memory and the mind. "We've shown that time itself is a very powerful component of learning," said Henry H. Holcomb, a psychiatrist who heads a Johns Hopkins University group that studies how people remember. "It is not enough to simply practice something. You have to allow time to pass for the brain to encode the new skill." The researchers used a device that measures blood flow in the brain. They concluded it takes five to six hours for the memory of a new skill to move from a temporary storage site in the front of the brain to a permanent storage site at the back. During those six hours, said Holcomb, there is a neural "window of vulnerability" when that new skill can be easily eroded from memory if the person attempts to learn a second new skill. "If you were performing a piano piece for the first time and then immediately started practicing something else, then that will cause problems in retention of the initial piece that you practiced," said Holcomb. It would be better, he said, if the first practice session were followed by five to six hours of routine activity that required no new learning. A report on the study is to be published Friday in the journal "Science." "This is a new and important insight into the relationship between motor skill learning and neural activity," said Carolyn B. Cave, a psychologist and learning researcher at Vanderbilt University. She cautioned, however, that not enough is known to identify precisely how the successive learning of different skills could interfere with each other. "The brain is incredibly flexible," said Cave. "It may not be, for instance, that practicing the piano would interfere with what you learned just before from a tennis lesson. The two skills could use different parts of the brain." In the Hopkins study, the researchers used a positron emission tomography device, or PET, to measure blood flow in the brain of test subjects while they learned a motor skill. The people were placed in the PET and then taught to manipulate an object on a computer screen by using a motorized robot arm. The test required unusually precise and rapid hand movements that could be learned only through practice. During this learning process, the PET image showed that blood flow was most active in the prefrontal cerebral cortex of the brain. After the learning session, the test subjects were allowed to do unrelated routine things for five to six hours and were then retested. When operating the robot arm this time, the blood flow was most active in the posterior parietal and cerebella areas, said Holcomb. "This shift in the brain is necessary to render the memory invulnerable and permanent," he said. "What we see is the consolidation of the memory." It is such a consolidation, said Holcomb, that allows a person to never forget some skills, such as riding a bike or swimming, that were learned as a child. Some of the Hopkins test subjects were trained in a new motor task immediately after learning the first skill. Later, those subjects were tested on how much of the first lesson they remembered -- and had lost much of the skill they had learned first. "If we teach one task and then immediately introduce a new task, we know that will largely erase any learning gained from the first task," said Holcomb. "But if we wait five to six hours and then give them a new task, then we don't erase what was learned in the first lesson." By PAUL RECER, AP Science Writer <http://www.nando.net/newsroom/ntn/health/080797/health17_7987.html> ---------------------------------------------------------------------------- [log in to unmask]