Fear and Reward: Role of Dopamine in Predictive Learning

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The ability to make predictions about the world and update those predictions with new information is essential to everyday functioning. The current research program seeks to shed light on how dopamine and target brain structures processes the establishment of predictive learning and how these predictions can be modified in the face of changing contingencies in the appetitive and aversive settings. The project will employ a combination of causal (optogenetics) and correlational (in vivo electrophysiology) neuroscience techniques in order to examine how excitation and inhibition of specific neuronal types (dopamine cells) lead to alternation in learning, behavior, and neural firing in brain areas that receive direct dopamine input. This project will specifically seek to determine whether dopamine processes learning about fear and reward in similar or opposing fashion. This will be done by employing a blocking design and examining whether dopamine regulates learning via error-correcting or value mechanisms, whether it plays a role in regulating attentional processes, as well as determine what information is carried by the dopamine signal at time of prediction and whether inhibiting this signal reinstates learning and neural firing to expected rewards. This research will shed important light on dopamine function in learning more generally by looking at both fear and reward learning. This work will also seek to examine how dopamine modulates processing in downstream brain areas under conditions when previously established associations are modified or updated in particular when expected outcomes are greater than those delivered. Such training defines the conditions for reduction or extinction in the already established predictive relationship between stimuli. By examining the involvement of circuits, the present proposal will lead to more holistic understanding of how information is propagated to target structures in order to process predictions. Furthermore, by examining the neurobiology of how associations are established and in turn extinguished in both the reward and fear settings, the proposed research carries important benefit to improving our understanding of animal models of disorders of affect (e.g., phobias, anxiety, post-traumatic stress) drug and food addiction, and ultimately the human experience. Thus the research proposed here seeks to speak to clinicians and the general population alongside academics and underscores the importance of animal work in treatment development. In addition, the diversity of the research carried by Dr Iordanova will served to develop a variety of analytical and technical skills in the new generation of scientists.