Study: Songbirds' vocal muscles work like human singers'

DECATUR, Ala., Jan. 12 (UPI) -- Bengalese finches use a dynamic muscular system to belt out their songs. According to new research out of Emory University, the birds utilize their singing muscles in a manner similar to human singers and speakers.

"Our research suggests that producing really complex song relies on the ability of the songbirds' brains to direct complicated changes in combinations of muscles," Samuel Sober, a biologist at Emory, said in a press release. "In terms of vocal control, the bird brain appears as complicated and wonderful as the human brain."

The work of Sober and his colleagues suggests the songbird's musical mechanics may even be more complicated than those of humans.

Pitch is central to the finch's vocal repertoire. Pitch isn't controlled a single muscle, but is manipulated by a variety of muscles working in concert.

Humans control pitch, amplitude and timbre via vocal muscles, or cords, in their voice box, or larynx. A bird's muscular equivalent of the voice box is called the syrinx. The syrinx, however, holds not one but two sets of vocal cords, which can harmonize two pitches simultaneously.

"Lots of studies look at brain activity and how it relates to behaviors, but muscles are what translates the brain's output into behavior," Sober explained. "We wanted to understand the physics and biomechanics of what a songbird's muscles are doing while singing."

Researchers used a technology called electromyography to monitor electrical activity of muscle tissue and measure how the finches' brains delivered song-related messaging to its vocal cords.

Sober said the results showed the neural algorithms involved in singing incorporate "complex redundancy."

"It tells us how complicated the neural computations are to control this really beautiful behavior," he said.

The findings work neatly with previous research that showed songbirds build a catalog of melodies and develop a signature song by duplication and augmentation.

The new findings were published in the Journal of Neuroscience.