Molecular and genomics insights into the neurobiological basis of vocal learning in birds

Songbirds and other vocal learning bird groups (parrots, hummingbirds) are among the few animals that learn to vocalize by imitating an adult tutor. Examination of their vocal learning abilities and associated brain pathways, particularly in zebra finches, has led to unique insights into the neurobiology of learned vocalizations, with implications for human speech and language mechanisms. Differential screening efforts have helped to identify candidate genes that may regulate the properties of the vocal learning and production pathways. A comprehensive in situ hybridization database, presented as an online molecular atlas of the zebra finch brain (http://www.zebrafinchatlas.org), has revealed the expression of selective markers across major vocal nuclei, as well as broad features of the molecular organization of the avian brain, including the identification of candidate avian homologues for cortical and sub-cortical structures. Comparative genomics has led to the discovery of lineage-specific features that may be associated with the evolution and/or control of vocal learning. Current efforts have also focused on the challenges of developing efficient gene manipulations strategies in finches and other avian species, to gain further mechanistic insights into vocal learning processes.