Graduate Training in Neuroscience
University of Washington
Professor, Departments of Biology & Otolaryngology; Co-Director, Neuroscience
I am interested in the detailed cellular mechanisms by which brains learn things. We are using vocal learning in songbirds as a model system for vocal learning in humans, and also for motor learning in general. Young songbirds learn their song first by memorizing the song of a nearby individual, usually the father. Later, they begin to vocalize and slowly match their own vocalizations to the memory of their "tutor". The tutor does not need to be present during the practice phase, but the bird needs to have intact hearing. When the young bird achieves a good match of the tutor song, his song becomes highly stereotyped, and its maintenance becomes somewhat less dependent on hearing. Extensive information concerning the brain structures involved in song production and learning, combined with detailed subcellular understanding of synaptic plasticity phenomena such as long- term potentiation (LTP) in the mammalian hippocampus, allow us to make testable hypotheses regarding the cellular interactions that underlie this behavior. We are using in vitro brain slices obtained from zebra finches to study synaptic mechanisms and plasticity in this system. The goal of this approach is to link cellular and synaptic events with behavior, and we plan to use knowledge gained from in vitro work to guide experiments to investigate the role of synaptic plasticity in song learning in vivo.
A second project in the lab concerns a circuit essential for vocal learning but not adult song production, the so-called anterior forebrain circuit. We are testing the hypothesis that this pathway corresponds to the mammalian cortico-basal ganglia-thalamocortical loop. We have provided strong evidence for functional similarities in the neurotransmitters used in some portions of this pathway and are continuing to explore the implications of this hypothesis at cellular, systems and behavioral levels. Tying this learning circuit to a well-studied pathway in mammals will allow work in avian and mammalian systems to be mutually beneficial.