Beyond harmonic sounds in a simple model for birdsong production

AMADOR, ANA; SITT, JACOBO; GOLLER , FRANZ; MINDLIN GABRIEL B.

Washington, USA

Congreso; society for neuroscience meeting; 2008

Society for Neuroscience

Birdsong has become an animal model system for the study of learned vocalizations with remarkable parallels to human vocal development and sound production mechanisms. Songs of many species are composed of a diversity of acoustically different elements called syllables. Each syllable is generated by the vocal organ through execution of synergetic physiological instructions.In the last years, a number of mathematical models have been proposed in order to integrate a large body of experimental work with the expected mechanical processes involved in birdsong production. Most of the studied species where the ones that produce nearly tonal sounds, like Northern cardinals (Cardinalis cardinalis), Canaries (Serinus canaria) and Chingolos (Zonotrichia capensis). However, the mechanisms of how the avian sound source might contribute to spectral richness are largely unknown. In order to address this question, we analyze the song of the Zebra finch (Taeniopygia guttata), that presents syllables with low fundamental frequencies that are spectrally rich, and syllables with high fundamental frequency that are nearly tonal.The characteristics found in the Zebra finch song can be synthetized with a nonlinearly enhanced flapping model for birdsong production. In this work we present a dynamical analysis of this model. We show that the same model is capable of generating tonal sounds and can present, for a wide range of parameters, solutions which are spectrally rich. Moreover, specific relationships between different acoustic features of the uttered sounds can be found in the synthetic sounds produced by our model. The role of physiologically sensible parameters is discussed in each oscillatory regime, allowing us to interpret previously reported data as well as proposing new experimental work.