Specific neurons in the brains of juvenile zebra finches selectively respond to the song of an adult bird known as the tutor (usually the father), but not to the song of other adult birds. These results, described in a paper published in Nature Communications, provide insight into the neural mechanisms underlying formation of song-related memories and early learning in birds.
It is known that juvenile zebra finches learn to sing by memorizing and precisely imitating the song of an adult tutor. This process requires that a specific memory of a given tutor’s song be formed. However, direct evidence for neural activity patterns related to this memorized song has been lacking.
Yoko Yazaki-Sugiyama recorded neuronal activity in the caudomedial nidopallium (NCM) - a brain region implicated in song learning in juvenile birds - in 20 male juvenile zebra finches before and during song learning, as well as in control birds of the same species and age. They presented the birds with nine different song stimuli, including from individuals of the same species and from different species, and measured the neuronal responses in the NCM. The authors found that a small number of neurons increased their activity (so-called ‘firing’) only when following exposure to the tutors’ song and not in response to any of the other eight sound stimuli. In addition, they showed that, overall, neuronal responses to song stimuli increased after exposure to the nine song stimuli, and that this response was dependent on neuronal circuitry (GABAergic circuits) and sleep.
Further research will help determine how these song-selective neurons interact with other brain areas to guide bird song learning during development. Studying the birdsong system may also lead to novel insights into human language acquisition.