Songbirds’ brains coordinate singing with intricate timing
As a bird sings, some neurons in its brain prepare to make the next sounds while others are synchronized with the current notes—a coordination of physical actions and brain activity that is needed to produce complex movements, new research at the University of Chicago shows.
In an article in the current issue of Nature, neuroscientist Daniel Margoliash and colleagues show, for the first time, how the brain is organized to govern skilled performance—a finding that may lead to new ways of understanding human speech production.
The new study shows that birds’ physical movements actually are made up of a multitude of smaller actions. “It is amazing that such small units of movements are encoded, and so precisely, at the level of the forebrain,” said Margoliash, a professor of organismal biology and anatomy and psychology at UChicago.
“This work provides new insight into how the physics of controlling vocal signals are represented in the brain to control vocalizations,” said Howard Nusbaum, a professor of psychology at UChicago and an expert on speech.
By decoding the neural representation of communication, Nusbaum explained, the research may shed light on speech problems such as stuttering or aphasia (a disorder following a stroke). And it offers an unusual window into how the brain and body carry out other kinds of complex movement, from throwing a ball to doing a backflip.
“A big question in muscle control is how the motor system organizes the dynamics of movement,” said Margoliash. Movements like reaching or grasping are difficult to study because they entail many variables, such as the angles of the shoulder, elbow, wrist and fingers; the forces of many muscles; and how these change over time,” he said.
"With all this complexity, it has been difficult to determine which of the many variables that describe movements are represented in the brain, and which of those are used to control movements," he said.
"It’s difficult to find a natural framework with which to analyze the activity of single neurons. The bird study provided us a perfect opportunity,” Margoliash said. Margoliash is a pioneer in the study of brain function in birds, with studies that include how learning occurs when a bird sleeps and recalls singing a song.
