Songbirds offer clues to highly practiced motor skills...( The melodious sound of a songbird ma...),Health

The melodious sound of a songbird may appear effortless, but his elocutions are actually the result of rigorous training undergone in youth and maintained throughout adulthood. His tune has virtually crystallized by maturity. The same control is seen in the motor performance of top athletes and musicians. Yet, subtle variations in highly practiced skills persist in both songbirds and humans. Now, scientists think they know why.

Their finding, reported in the current issue of Nature, suggests that natural variation is a built-in mechanism designed to allow the nervous system to explore various subtle options aimed at maintaining and optimizing motor skills in the face of such variables as aging and injury.

While the study was conducted in the adult male Bengalese Finch, a perky fellow who uses his song to woo females, the finding has implications, the scientists say, for understanding the way in which adult humans perform and retain well-learned motor skills. More broadly, the study provides insights that could inform strategies for rehabilitating patients following strokes and other damage to the nervous system.

Many neuroscientists have thought that the nervous system simply didnt have the ability to control movement at a highly precise level, says lead author Evren Tumer, PhD, a postdoctoral fellow in the laboratory of senior author Michael Brainard, PhD, UCSF assistant professor of physiology. After all, were not machines. But our study suggests that subtle variation can serve a purpose and contribute to the maintenance of motor skills.

If a golfer had a perfect swing, and all the conditions within him and the external environment were static, this wouldnt be necessary, he says. But there are always changes muscles get tired or are fresher, neurons die or change with age. There is always a bit of change somewhere in the system.

To keep tuned up, says Brainard, the nervous system constantly needs to experiment, to co
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