A multisensory integrative forebrain area (NCC) in female zebra finches discriminates between normal and abnormal...

For many species, vocal communication is an essential part of mate selection and courtship. In songbirds, such as zebra finches (Taeniopygia guttata), a male's song can reveal much about his physiology and potentially even his developmental history, influencing female mate choice. It is thought that female zebra finches possess an auditory 'template' - potentially represented in the caudomedial nidopallium (NCM), caudomedial mesopallium (CMM), and/or caudocentral nidopallium (NCC) - that provides a standard for high- and low-quality song and guides behavioral preference. To investigate how finely tuned this template is to subtle differences in song, we employed an operant conditioning paradigm, using normal conspecific songs and Parkinsonian-like songs, which were derived from males overexpressing the human alpha-synuclein gene in Area X of the song circuit. Additionally, females were exposed to playbacks of these songs for immunohistochemical analysis of Zenk and c-Fos - protein products of the immediate early genes (IEGs) zenk and c-fos, respectively - in the NCM, CMM, and NCC. While the behavioral preference for either song type was inconsistent between females, females exposed to normal song exhibited significantly higher expression of both IEGs as compared to females exposed to Parkinsonian-like song in the NCC, but not in the NCM or CMM. These results suggest that the NCC may serve as a neural detector of subtle differences in song quality, while the NCM and CMM may influence preference behavior more directly.