January 8, 2013
Researchers Use 3D Visualization To Study Songbird Song
Brett Smith for redOrbit.com — Your Universe Online
Since both human and songbird infants learn vocal communication at an early age, the cognitive mechanisms behind bird songs have a rich history of groundbreaking research. However, an international team of scientists decided to take a deeper look into the physical mechanics behind birds´ vocalizations, according to a new study in the open access journal BMC Biology.
"We know quite a bit about how the songbird brain codes and decodes songs and how young songbirds learn to imitate the songs of their adult fathers. But we know very little about the instrument itself, the vocal organ called syrinx,” said the study´s senior author Coen Elemans, from the University of Southern Denmark.
As you are undoubtedly able to read these words and understand their meaning, you understand that the ability to communicate is important for all animals. That ability directly translates into a bird´s ability to survive, as they use it to avoid predators, signal their identity, and find a mate.
"Songbirds in particular excel at vocal communication,” explains Elemans, noting that most songbirds rapidly riff through a series of notes, even when the bird is in constant motion. "Just imagine an orchestra musician playing his instrument while performing a dance. How do birds do this?"
To better understand the physiological mechanism behind the songs, the research team created three-dimensional PDF models of the parts of a zebra finch´s skeleton, soft tissues, cartilaginous pads, and muscles used in sound production. The models were designed to show how the birds use their strength and light physiology to shift the vibrating membranes of the syrinx at superfast speeds in great detail.
"We show how the syrinx is adapted for superfast trills and how it can be stabilized while the bird moves,” Elemans said. “Also we emphasize how several muscles may work together to control for example the pitch or volume of the sound produced.”
The computer models also allowed the scientists to identify a previously unrecognized Y-shaped structure on the birds´ sternum that correlates to the shape of the syrinx. The researchers theorized that it could help even out sound production.
"This study provides the basis to analyze the micromechanics, and exact neural and muscular control of the syrinx,” said Elemans. “For example, we describe a cartilaginous structure which may allow the zebra finch to precisely control its songs by uncoupling sound frequency and volume."
He added that, "the results lay down the foundation for our understanding of how songbirds can undertake such complex vocal acrobatics, so we can unravel the mystery of how songbirds produce some of nature's most inspiring sound compositions."
In their report, the scientists said future research should focus on assessing muscle function during singing. They suggested muscle stimulation experiments in controlled environments and during resting and singing could be helpful in better understanding the vocal mechanism. The result of these experiments could show direct analogs between structural components and specific notes or vocalizations. These future experiments might also allow for the complete ℠story´ of a birdsong to be told–from neural patterns to audible sounds.