Why are parrots such great vocal imitators?

Brett Smith for redOrbit.com – @ParkstBrett

The unique brain mechanism behind certain parrots’ ability to replicate human speech has baffled scientists for decades, but now it appears a new game-changing study has found a shell structure around the vocal learning centers in parrot brains.

Published in the journal PLOS ONE, the study revealed brain constructs that had gone unacknowledged in research published over the last 34 years. The study team said their results might give clues about the neural components of human speech.

“This will open up a whole new branch of research involving different types of brains and brain regions,” study author Mukta Chakraborty, a post-doctoral researcher at Duke University, told redOrbit in a recent interview.

Parrots are considered vocal learners, which means they can mimic sounds. Until now, the common pet parakeet was the only species whose brain had been probed for the components of vocal learning.

In the study, researchers used brain tissue from eight parrot species besides the common parakeet, including tissue from conures, cockatiels, lovebirds, Amazon parrots, a blue and gold macaw, a kea and an African Grey parrot. The tissues were examined using a radioactive genetic technique to look for the activity of a particular gene common to the brains of both humans and song-learning birds.

“It’s sort of like a functional MRI,” Chakraborty said. “If you’re going to look for expression patterns of the gene, you conduct this procedure that allows you to map its expression across the entire brain and different brain sections.”

Vocal learners have something in common

By looking at the expression pattern of their target gene, the researchers saw all these vocal learners had a previously unidentified shell around the core of their vocal learning centers, even in the most ancient of the parrot species they studied, the Kea of New Zealand. This finding indicates that the populations of neurons in the shells probably arose a minimum of 29 million years ago, the report said.

“The first thing that surprised me when Mukta and I were looking at the new results is, ‘Wow, how did I miss this all these years? How did everybody else miss this all these years?’” study author Erich Jarvis, a member of the Duke Institute for Brain Sciences, said in a news release. “The surprise to me was more about human psychology and what we look for and how biased we are in what we look for. Once you see it, it’s obvious. I have these brain sections from 15 years ago, and now I can see it.”

Chakraborty said she envision her research continuing with parrots and focusing on the functional specializations of the newly found brain structure. She said she plans to use genetic manipulations “to actually figure out what the shell structure is doing.”


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