Bird brain growth is focus of study

SEATTLE, July 23 (UPI) -- U.S. scientists have discovered at least one species of songbird relies on steroids to increase the size of its song-producing brain areas.

University of Washington Professor Eliot Brenowitz and colleagues showed the white-crowned sparrow uses testosterone, a natural steroid, to trigger the seasonal growth of its song-producing brain regions. The University of Washington scientists also determined such growth doesn't require hearing or high levels of singing.

"This is surprising to a lot of people because many thought seasonal growth of song nuclei was related to the rate of singing," said Brenowitz. "This study suggests playing tapes of recorded speech to try to help a person recover language after a stroke might not be productive. But perhaps we could use neutrophins -- growth-inducing proteins whose synthesis by brain neurons is stimulated by testosterone."

In sparrows, brain areas are directly stimulated by these hormones to grow and one day such hormones might possibly help repair brain damage caused by strokes or neurodegenerative diseases, he said.

The study, which included Professor Edwin Rubel and researcher Karin Lent, appeared in last month's issue of the Journal of Neuroscience.