Q: What do songbirds dream about? A: Singing

Songbirds dream of singing, and may be rehearsing the songs they will sing the following day, new American research suggests.

Songbirds dream of singing, and may be rehearsing the songs they will sing the following day, new American research suggests.

Scientists at the University of Chicago have drawn the remarkable conclusion from studying the electrical brain activity of Australian zebra finches. They found that sleeping birds fire their neurons in complex patterns similar to those generated when they are awake and singing.

The activity patterns vary slightly - as if the birds are rehearsing a range of slightly different songs, sometimes with slower or faster tempos - and this, the researchers believe, is precisely what they are doing.

The study, reported in the journal Science, suggests sleep plays a central role in the learning process. Song acquisition by birds is often used as a model for how humans learn to talk.

"From our data we suspect the songbird dreams of singing," said Professor Daniel Margoliash, who led 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 Chicago team used sophisticated miniature recording devices to measure the activity of individual brain cells in four zebra finches. Firing patterns of separate cells in musical areas of the Australian songbird's brain were recorded.

When the recording was played back to a sleeping bird, the neurons in its brain fired in a pattern identical to that which accompanied singing, although the bird produced no sound. During undisturbed sleep, the neurons spontaneously fired the same complex song production patterns in bursts.

The scientists questioned how the bird learned to correct its song when by the time the tune was heard the neurons were now engaged in creating the next sound. They decided that practise during sleep may be part of the answer.