title: Behaviourally driven gene expression reveals song nuclei in hummingbird brain.
abstract: Hummingbirds have developed a wealth of intriguing features, such as backwards flight, ultraviolet vision, extremely high metabolic rates, nocturnal hibernation, high brain-to-body size ratio and a remarkable species-specific diversity of vocalizations. Like humans, they have also developed the rare trait of vocal learning, this being the ability to acquire vocalizations through imitation rather than instinct. Here we show, using behaviourally driven gene expression in freely ranging tropical animals, that the forebrain of hummingbirds contains seven discrete structures that are active during singing, providing the first anatomical and functional demonstration of vocal nuclei in hummingbirds. These structures are strikingly similar to seven forebrain regions that are involved in vocal learning and production in songbirds and parrots--the only other avian orders known to be vocal learners. This similarity is surprising, as songbirds, parrots and hummingbirds are thought to have evolved vocal learning and associated brain structures independently, and it indicates that strong constraints may influence the evolution of forebrain vocal nuclei.
authors.affiliation: Department of Neurobiology, Duke University Medical Center, Durham, North Carolina 27710, USA. jarvis@neuro.duke.edu
authors.forename: E D
authors.initials: ED
authors.lastname: Jarvis
authors.forename: S
authors.initials: S
authors.lastname: Ribeiro
authors.forename: M L
authors.initials: ML
authors.lastname: da Silva
authors.forename: D
authors.initials: D
authors.lastname: Ventura
authors.forename: J
authors.initials: J
authors.lastname: Vielliard
authors.forename: C V
authors.initials: CV
authors.lastname: Mello
mesh_terms: D000818:Animals; D005075:Biological Evolution; D001717:Birds / Q000033:anatomy & histology / Q000502:physiology*; D001921:Brain / Q000033:anatomy & histology / Q000502:physiology*; D001931:Brain Mapping; D004268:DNA-Binding Proteins / Q000235:genetics; D005247:Feeding Behavior; D005786:Gene Expression Regulation; D016548:Prosencephalon / Q000502:physiology; D014157:Transcription Factors / Q000235:genetics; D014828:Vocalization, Animal / Q000502:physiology*
chemical_list: D004268:DNA-Binding Proteins; D014157:Transcription Factors