Young songbirds babble before they can mimic an adult’s song, much like their human counterparts. Now, in work that offers insights into how birds–and perhaps people–learn new behaviors, MIT scientists have found that immature and adult birdsongs are driven by two separate brain pathways, rather than one pathway that slowly matures.
“The babbling during song learning exemplifies the ubiquitous exploratory behavior that we often call play but that is essential for trial-and-error learning,” comments Michale Fee, the senior author of the study and a neuroscientist in the McGovern Institute for Brain Research at MIT and an associate professor in MIT’s Department of Brain and Cognitive Sciences.
Early on, baby zebra finches produce a highly variable, babbling song. They practice incessantly until they can produce the stereotyped, never-changing song of adults. “This early variability is necessary for learning, so we wanted to determine whether it is produced by an immature adult motor pathway or by some other circuit,” Fee explains.
Past research has shown that the zebra finch has two distinct brain circuits dedicated to song, one for learning and another – known as the motor circuit – for producing the learned song. Damage to the first circuit while the bird is still learning prevents further learning, so the song remains immature. Yet in an adult that has already learned its song, disabling the learning circuit has no effect on song production.