Does social segregation prevent a proper development of a central auditory area in a female songbird?
Résumé
Direct social contact and social interaction affect both speech development in human infants and song learning in songbirds, and are required in order to maintain perceptual abilities. However, the processes involved are still poorly known. In the present study, we tested the hypothesis that social withdrawal would prevent the proper development of a central auditory area, using an established animal model of vocal development, a songbird. Based on our knowledge of European starlings' vocal behaviour and development, we raised young female starlings with peers and adult male tutors only. This ensured that these females would show neither social bond with nor vocal copying from males. Electrophysiological recordings performed when these females were adult revealed perceptual abnormalities: they presented a larger auditory area, a lower proportion of specialized neurons and a larger proportion of generalist sites than wild-caught females, whereas these characteristics were similar to those observed in socially deprived (physically isolated) females. These results confirmed, and added to, earlier results for males, suggesting that the degree of perceptual deficiency reflects the degree of social withdrawal. To our knowledge, this report constitutes the first evidence that the lack of social interactions can, as much as physical separation, alter the development of a central auditory area.