The brains of budgerigars, better known in the United States as parakeets, have clusters of neurons that light up when they tweet specific notes, much like the patterns driving human speech.
Credit: Christopher Auger-Dominguez
Humans are by nature a highly social species. Many of us can spend hours chatting and storytelling with friends, family, and colleagues. But an estimated 15 percent of people in the United States have a communication disorder, including ones that disrupt how they share or receive information, preventing them from either planning what they鈥檙e going to say or getting the words out. A new study may help decode the complex process that causes speech to break down among those who have autism, have suffered a stroke or a traumatic brain injury, or have another speech-impairing condition.
For the first time, 黑料福利社 Langone Health has recorded the brain activity of another highly social species鈥攖he small, long-tailed Australian parrots known as budgerigars, commonly called parakeets in the United States鈥攁s they communicated with each other. Our researchers found that the budgerigar brain has clusters of neurons that light up when they make specific notes, like the patterns that drive human speech.
The study, , reveals the presence of a humanlike brain map that allows parrots to readily produce a wide range of sounds by using a kind of 鈥渧ocal keyboard.鈥 Senior author , the Thomas and Suzanne Murphy Professor of Neuroscience and Physiology and a professor in the , compares the discovery to figuring out the piano keys that correspond to each component of their song.
鈥淲e鈥檝e finally found a species other than humans that has this map, providing an important parallel to human speech,鈥 says Dr. Long. Understanding the rules and steps governing parrot vocalizations, he adds, could lead to new insights into the brain processes that underlie normal and disordered language use in humans.
One bird that has long been studied in animal communication, a songbird called the zebra finch, imitates the short courtship song of an older tutor by practicing it hundreds of thousands of times to make a perfect copy. Another animal, the Costa Rican singing mouse, sings an elaborate song to mark and defend its territory. Dr. Long has studied both species, which share complementary vocal strategies with humans even though they can produce only a limited sound repertoire.
The budgerigar, by contrast, is a masterful mimic that can learn and repeat hundreds of human words, and an enthusiastic storyteller that can engage in elaborate dialogues with other budgerigars. To better understand its exceptional ability to learn and produce new sounds, Dr. Long and postdoctoral researcher Zetian Yang, PhD, tracked the brain activity of the birds as they communicated with each other.
When one of the parrots sang specific notes akin to human vowels or consonants, the researchers saw corresponding nerve cells light up in the anterior arcopallium, a key part of the avian forebrain. 鈥淲e can look at the activity of just five of the neurons and know what the bird is singing without listening to the song,鈥 Dr. Long says.
To encourage the budgerigar banter, researchers created a cocktail party鈥搇ike arena in the shape of a figure eight. At one end, they placed a single parakeet behind a clear window so they could simultaneously record both its singsong messages and brain activity. At the other, they grouped another four parrots together, allowing them to spend hours chitchatting with each other and the distant bird through the window.
鈥淲hen we looked at the parrot鈥檚 pattern of brain activity, we asked the question 鈥楧oes it resemble what we have seen in the songbird or what has been observed in the human brain?鈥 says Dr. Long. 鈥淭he answer, resoundingly, is 鈥業t鈥檚 more like a human.鈥欌
Once the researchers learn more about the mechanics of budgerigar songs, they hope to be able to translate what the birds are telling each other. In the meantime, the plans further explorations that could inform our understanding of the brain processes that go awry in communication disorders.
鈥淲hat we want to find out now is: How does a bird recall something from its environment and make those sounds in order to interact with another bird?鈥 explains Dr. Long. 鈥淭his study opens enormous possibilities for understanding how this amazing creature does this and gaining insight into how humans do it, how these processes break down, and how to fix them once that happens.鈥
