Gene products produced for speech in the human brain correspond to similar molecules in the vocal communication areas of the brains of zebra finches and parakeets, they said, but not in the brains of doves and quails -- vocal birds that do not "learn" their sounds.
"The results suggest that similar behavior and neural connectivity for a convergent complex trait like speech and song are associated with many similar genetic changes," Duke neurobiologist Erich Jarvis said.
Jarvis and his collaborators have found songbirds have a connection between the front part of their brain and nerves in the brainstem that control movement in muscles that allow songs in birds, a Duke release reported Thursday.
Humans also have this motor learning pathway for speech, they said.
Jarvis said he had developed a motor theory for the origin of vocal learning, which describes how ancient brain systems used to control movement and motor learning then evolved into brain systems for learning and producing song and spoken language.