Neural mechanisms underlying vocal learning in zebra finches

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Learning a motor skill often involves transforming an internal neural template that has been shaped by observation into a series of motor commands. To reach the desired movement, it is necessary to practice many times and compare the performance to the template. Learning to serve a tennis ball, for instance, involves observing a teacher, rehearsing your serve and recognizing your mistakes while practicing. The neural mechanisms underlying the process of motor skill learning are not well understood. I address this issue in the zebra finch, a songbird that acquires its song via observational learning: zebra finches listen to their tutor to form a neural song template, integrate this template into their motor program, and compare their ongoing song performance to the template. Zebra finches have interconnected, dedicated neural pathways for auditory processing, motor production and song learning and are thus particularly well suited for studying how sensory information is translated into motor performance on a neuronal level. To explore interactions between neural circuits during motor learning it is important to measure the synaptic inputs and outputs of these circuits during behavior. Intracellular recordings enable us to monitor network activity from the perspective of a single cell and are the ideal technique to measure the underlying neural dynamics within and across networks. The intracellular microdrive represents a novel tool to measure synaptic inputs onto single cells during behavior. During my postdoc I helped to develop the intracellular microdrive and used it to investigate sensorimotor integration in the premotor nucleus of adult and juvenile zebra finches during singing and listening. In the future I plan to perform intracellular recordings in freely behaving zebra finches at various developmental stages both in higher-order auditory areas and areas responsible for motor production and learning. These experiments will reveal the synaptic profile of neurons during the formation of the template and clarify how the performance improvements that practice affords are encoded at the cellular level. The specific aims of my research proposal are 1) to investigate how higher-order auditory areas represent the song template in order to elucidate how the template is integrated into the motor circuit during song rehearsal and 2) to explore how the output signal sent by the motor pathway is critically evaluated against the target template to improve motor performance.