Finch fathers sing to their chicks while they’re young, and eventually the baby birds will start to mimic them. Over time, they’ll master the song and pass it down to their own offspring. In a way, zebra finches show a simplified version of human vocal development.
But in the new study, the researchers bypassed this process and directly manipulated the brains of young finches, teaching them parts of a song without any kind of tutoring from their parents.
They managed this using optogenetics, a technique where flashes of light are used to stimulate certain neurons in the brain. In this case, the scientists manipulated the connection between the part of the brain that processes what the animal hears, and the part that controls the vocal “motor.” In effect, they were creating auditory memories that would normally be coming from outside, and the bird would naturally try to mimic the signals.
The researchers used a kind of Morse code to teach the finches how long syllables of the song should be. Longer pulses of light told them to sing longer syllables, and vice versa. And sure enough, the birds eventually learned to sing along, even though they’d never been taught by an adult finch….[ ]