Birdsong has established itself as one of the most powerful model systems for the study of complex learned behaviors. Much of the strength of the system lies in the ease with which the behavior can be quantified and the prominence of the highly specialized nuclei, known collectively as the song system, which are involved in song learning and production. In addition, because song learning in birds and language acquisition in humans are both dependent on auditory feedback, the study of birdsong learning is likely to provide insights into the mechanisms underlying vocal development in humans. The long-term goal of our laboratory is to understand how the nervous system encodes complex learned motor behaviors, such as song, as well as study how auditory feedback signals shape song motor networks during song learning.

In my talk I will discuss two ongoing projects that aim to understand the nature of auditory/motor interactions in a key brain structure of the avian song system. This structure, nucleus HVc, lies at the interface of the auditory and motor systems. In the first project, I will discuss the functional organization of the vocal motor pathway by comparing neural activity patterns recorded during singing across hemispheres. Our finding that song premotor activity is highly synchronized across hemispheres despite the lack of direct connections (birds do not have a corpus callossum) suggests an important role for midbrain vocal areas in controlling song pattern generation. In the second project, I will discuss exciting results showing that auditory processing in HVc is highly state dependent. Specifically, we find that auditory responses, which are robust and highly selective in anesthetized birds, become largely suppressed in awake birds. This state-dependence of auditory responses will be discussed in the context of processing of auditory feedback signals during singing.