Auditory-responsive units in the midbrain vocal nuclei in the ring dove (Streptopelia risoria)

The avian midbrain vocal control nucleus, n. intercollicularis (ICo), receives inputs from midbrain auditory nucleus and from a subdivision of auditory thalamus, suggesting a possibility of auditory response units in the ICo. Using single-unit recordings, we explored auditory response units throughout the dorsomedial midbrain of female ring doves under deep general anesthesia (acute preparation). We found exclusively in the ICo, units that responded preferentially to taped courtship coos of conspecifics (male or female coos) and units that responded to specific frequencies present in coos. Units in the midbrain auditory nucleus also responded to these auditory stimulation in a tonotopic fashion, and were responsive to tone burst as well. The results, along with data from other experiments, suggest that species-specific sound responsive units within the ICo may mediate acoustically facilitated female coos and endocrine responses of the ring dove.