Responses to natural classes of songs in the auditory telencephalon of adult male starlings
Résumé
The 'song control system' has been defined as a set of interconnected brain nuclei found only in songbirds. These nuclei have a clear and primary role in the motor control of song production. The neural systems responsible for sensory representation of songs are less well defined. In order to broach this question, we studied neuronal responses to a variety of natural species-specific and artificial non-specific stimuli in the auditory telencephalon of awake-restrained adult male starlings. Starlings are highly social songbirds that sing three distinct classes of songs used for species-, population- and individual-specific recognition. These three classes of songs reflect increasing complexity in information, going from species-specific to individual identity. They thus appear as a good model to study where in the brain, and how, behaviourally-relevant sounds corresponding to structurally and functionally distinct classes of natural communication signals are processed. In order to see how neurons may respond differently to classes of songs that had been described by field observations, we recorded neuronal responses to artificial non-specific sounds and to natural songs belonging to the three classes of songs used by starlings, in awake-restrained adult male starlings. Our results show differential neuronal responses to behaviourally-defined classes of songs. These data give us clues to functional categorization of natural communication signals, and to individual vocal recognition of same-species members, in which songs are associated with individuals or groups of individual conspecifics.