"It's an extraordinary finding," says Sarah Bottjer of the University of Southern California. "Here's an organism that enables a direct investigation of how animals learn motor activities."
The songbird's creative, trial-and-error type of learning provides an ideal model for studying similar processes in humans, such as how a baby's babble takes on the conversational cadences and recognizable syllables of mama and papa. Likewise, the brain pathways involved in birdsong have a human counterpart, the poorly understood basal ganglia circuit, so birds may have something to teach us about our own brains and what we learn may eventually apply to human diseases that affect motor abilities, such as Parkinson's disease.
"The question we're trying to answer is how a young bird learns its song," says Professor Michale Fee of MIT's McGovern Institute about his recent study, which was published online in advance of the May issue of the free access journal, Public Library of Science Biology. "We've known there are several brain areas involved: a motor circuit for producing the song, and a learning circuit, called the AFP (for anterior forebrain pathway), that sends its output to the motor system."
Normally, the young zebra finch nursery resounds with ever-new, imperfect variations of the adult songs. Gradually, the youngsters' songs become less variable and more true to the old standards. Some years ago, Bottjer had observed that disabling a young finch's AFP circuit stopped the learning in midstream. The bird still sings, but never learns the right song. To exp