Jon T. Sakata, Ph.D. - US grants

DESCRIPTION (provided by applicant): Whereas the neurobiology underlying singing behavior and the environmental and experiential factors that affect song development have been well characterized, little research to date has focused on the neural mechanism by which exogenous variables influence song. Here we propose to investigate the role of the ventral tegmental area (VTA) in modulating song change and in transducing reinforcing stimuli that have been found to affect song development. The VTA has been implicated in reinforcement learning in a variety of vertebrates, and the avian VTA is well situated to shape song because of its connections with telencephalic nuclei dedicated to singing behavior. In Specific Aim 1 of this proposal, we will assess the degree to which pairing VTA stimulation to the singing of particular song elements will change song. Because VTA activation is rewarding, we are essentially testing whether reward contingencies can affect song, and we predict that elements paired with VTA stimulation will become more prevalent over time. In Specific Aim 2, we will investigate what stimuli activate VTA neurons. We will assess VTA activity following food reward, the presentation of videos of conspecifics displaying different social behaviors and playbacks of conspecific and heterospecific songs. We will conduct these studies in the Bengalese finch, a bird with a large vocal repertoire. In the end, we will gain insight into the response properties of VTA neurons, the functional consequences of VTA activity on singing behavior and, more generally, a deeper understanding of the role of reward systems in vertebrate learning.