Virtual bird brain matches nature's tunes

8 January 2003

Adding a virtual brain to a computer model of a singing bird has allowed scientists to figure out how birds compose their songs. The feat hints that we might one day be able to map some of the complex circuitry in an animal’s brain just by listening to its calls.

When birds sing, they force air from their lungs past folds of tissue in the voice box. Just over a year ago, scientists at Rockefeller University in New York and the University of Buenos Aires in Argentina reported that they had developed a simple computer model that mimics this process to produce sound.

By simulating changes in the tension of the vocal folds and in the air pressure from the lungs, the model reproduced the song of a canary (New Scientist print edition, 10 November 2001).

But the song only sounded right if the lungs and the vocal folds vibrated with particular phase differences. That intrigued the Argentinian scientists, Rodrigo Laje and Gabriel Mindlin. How does a bird’s brain give these complex commands?


Some clues come from neurological studies, which show that a brain region called the high vocal centre is active when a bird sings. This activity excites neurons in another region called the RA nucleus. Some neurons in this structure excite motor neurons that control muscles in the vocal folds or in the lungs. Others damp down the activity of nearby neurons.

Complex bursts

When Laje and Mindlin made a simple computer model of the RA neurons, they were surprised to find that it changed a simple, constant signal from the high vocal centre into a complex series of bursts with the hallmark phase differences of birdsong.

And when they fed the output signal from the virtual brain into their computer model of a bird’s voice box, it once again sang like a bird. Simply varying the volume of the signal from the high vocal centre produced different song patterns.

The model bird can accurately echo the song of a South American sparrow. The fake sparrow song sounds extremely similar to the real one . The big surprise, says Mindlin, is that the intricacies of birdsong arise from such simple instructions. The results will appear in a future issue of Physical Review Letters.

Mindlin plans to add more brainpower to the virtual bird, allowing it to listen as well as sing. This might help reveal how birds perfect their songs as they learn them from other birds.

He hopes it might one day be possible to use similar models to map the neural circuitry of animals without distressing lab experiments – just by recording their calls and movements in the wild. It is even possible that a computer model tuned to “talk” human-like gibberish could say something about the architecture of our own brains.