The songbird as a model for the generation and learning of complex sequential behaviors.

Over the past four decades songbirds have become a widely used model organism for neuroscientists studying complex sequential behaviors and sensory-guided motor learning. Like human babies, young songbirds learn many of the sounds they use for communication by imitating adults. This remarkable behavior emerges as a product of genetic predispositions and specific individual experiences. Research on different aspects of this behavior has elucidated key principles that may underlie vertebrate motor learning and motor performance in general, including (1) the mechanisms by which neural circuits generate sequential behaviors, (2) the existence of specialized neuronal circuits for the generation of exploratory variability, (3) the importance of basal ganglia-forebrain circuits for learning sequentially patterned behaviors, including speech and language, and (4) the existence of genetic toolkits that may have been coopted multiple times during evolution to play a role in learned vocal communication, such as the transcription factor FoxP2 and its molecular targets. This review presents new techniques, experiments, and findings in areas where songbirds have made significant contributions toward understanding of some of the most fundamental questions in neuroscience.