Distinct contributions of converging neural pathways to auditory learning

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PROJECT SUMMARY/ABSTRACT Effective interpretation of sensory stimuli relies on the ability to discriminate stimulus features and link them to appropriate behavioral responses depending on past experience. Much remains unknown, however, about the roles that different neural pathways play in representing and learning these associations, and in particular, how information is distributed and combined among different pathways during learning and execution of behavior. As a step toward addressing the long-term goal of understanding how the nervous system flexibly links sensory stimuli to actions, this research will focus on auditory decision making to study the contributions of the multiple auditory pathways that target the striatum, the main input stage of the basal ganglia and a key structure in the regulation of motor behavior. Specifically, the project will focus on the flow of information from the auditory thalamus as well as primary and non-primary areas of the auditory cortex to the posterior tail of the striatum. The central hypothesis is that the various auditory cortical and thalamic pathways to the striatum all play distinct roles during learning and execution of sound-driven decisions. This work will consist of developing theoretical models of sound representation and learning in the multiple auditory pathways converging on the striatum, as well as carrying out experiments in mice trained to perform acoustic discrimination tasks in order to test and refine these models. These experiments will take advantage of novel techniques for reversible manipulation of specific neural pathways while monitoring large numbers of neurons simultaneously during behavior. The project is organized in three aims. The first aim is to determine the conditions in which auditory cortico-striatal and thalamo-striatal pathways play distinct roles during performance of sound-action association tasks. The second aim is to determine the roles of auditory cortical vs. thalamic pathways to the striatum during learning of these tasks. The third aim is to identify the acoustic features of natural sounds conveyed by distinct auditory cortical fields to the striatum. Together, these studies will reveal the computational roles played by converging neural pathways in acquiring and executing learned behaviors.