Erich Jarvis, Neurobiology

In our research, emphasis is placed on the molecular pathways involved in the perception and production of learned vocalizations. We use an integrative approach that combines behavioral, anatomical and molecular biological techniques.

The main animal model used is songbirds, one of the few vertebrate groups that evolved the ability to learn their vocalizations. The generality of the discoveries is tested in other vocal learning orders, such as parrots and hummingbirds, as well as non-vocal learners, such as pigeons and non-human primates. Some of the questions require performing behavior/molecular biology experiments in freely ranging animals, such as hummingbirds in the tropical forests of Brazil.

Recent results show that in songbirds, parrots and hummingbirds, perceptions and production of song are accompanied by anatomically distinct patterns of gene expression. All three groups were found to exhibit vocally-activate gene expression in forebrain nuclei that are in almost identical brain locations. These structures in songbirds are required for vocal learning during a critical period of juvenile development. The structures are thought to have evolved independently within the past 70 million years, since they are absent from interrelated non-vocal learning orders. One structure, Area X of the basal ganglia's striatum in songbirds, shows large differential gene activation depending on the social context in which the bird sings. These differences may reflect a semantic content of song, perhaps similar to human language.

Future work will address:

1. the function of the basal ganglia in vocal communication;
2. the evolution of vocal communication;
3. the molecules responsible for vocal learning during development;
4. the links between electrophysical activity and gene activation; and
5. the relationships between songbird vocalizations and human language.

The overall goal of the research is to advance our knowledge of the basic mechanisms of brain function and development for complex behaviors. These goals will be further achieved by combined collaborative efforts with the laboratories of Drs. Mooney and Nowicki at Duke University, who study respectively behavior and electrophysical aspects of vocal communication.