In a study that suggests that sleep plays a central role in the learning process, University of Chicago researchers show that sleeping songbirds replay, rehearse and, perhaps, reinforce the neuronal activity patterns of song production.
Song acquisition is often used as a model system for how humans learn speech. Young birds learn to sing by listening to adults and then practice by listening to their own attempts. In the October 27, 2000, issue of Science, the researchers describe how the neurons involved in song generation precisely recreate during sleep the complex activities involved in singing, though no sound is produced.
"From our data we suspect the songbird dreams of singing," said Daniel Margoliash, Ph.D., associate professor in the department of organismal biology and anatomy at the University of Chicago, and principal investigator in the study. "The zebra finch appears to store the neuronal firing pattern of song production during the day and reads it out at night, rehearsing the song and, perhaps, improvising variations. The match is remarkably good."
The recent miniaturization of neuronal recording gear allowed Margoliash's team to study the activity of individual brain cells in birds that were relatively free to move about and behave naturally.
"The single-neuron recording gives us a powerful tool for the study of sleep's importance to learning," said Margoliash.
The researchers were able to record the firing patterns of individual pre-motor brain cells of four zebra finches, a well-studied songbird native to Australia that weighs only about half an ounce.
The male zebra finch works hard to attract the female with his stereotyped song, and the brain structures that control singing are highly specialized for this behavior.
The researchers compared the activity of each neuron while the awake bird sang, while a sleeping bird could hear a recording of its own song, and during undisturbed sle
Contact: Jeanne Galatzer-Levy
University of Chicago Medical Center